RTL-SDR and GNU Radio with Realtek RTL2832U [Elonics E4000/Raphael Micro R820T] software defined radio receivers.

Originally meant for television reception and streaming the discovery and exploitation of the separate raw mode used in FM reception was perhaps first noticed by Eric Fry in March of 2010 and then expanded upon by Antti Palosaari in Feb 2012 who found that these devices can output unsigned 8bit I/Q samples at high rates.

The drivers and userspace tools that made rtlsdr what it is today were created by the osmocom people,

• librtlsdr - contains the major part of the driver
• rtl_sdr, rtl_tcp, rtl_test, etc - command line capture tools and utilities
• gr-osmosdr - gnuradio compatible module
• and a bunch of other stuff.

keenerd is the author of many other rtl_* tools: rtl_fm, rtl_power (heatmap.py), rtl_adsb and code changes accepted into the mainline.

rtl-sdr.com has the latest news and tutorials.

RF, DSP, and USB details

The dongles with an E4000 tuner can range between 54-2147 MHz (in my experience) with a gap over 1100-1250 MHz in general. The R820T and R820T2 go from 24-1760 MHz (but with reduced performance above 1500 MHz). The R820T dongles use a 3.57 MHz or 4.57 MHz intermediate frequency (IF) while the E4000s use a IQ pair Zero-IF. For both kinds the tuner error is ~30 +-20 PPM, relatively stable once warmed up, and stable from day to day for a given dongle. All of the generic dongle antenna inputs are 75 Ohm impedance (some SDR branded versions have 50 ohm input). The RTL2832 ADC differential input impedance is ~3,300 Ohm. The dynamic range for most dongles is around 45 dB. The sensitivity is somewhere around -110 dBm typically. The highest safe sample rate is 2.56 MS/s but in some situations up to 3.2 MS/s works without USB dropping samples (RTL2832U drops them internally). Because the devices use complex sampling (I/Q) the sample rate is equal to the bandwidth instead of just half of it. For the data transfer mode USB 2 is required, 1.1 won't work. Antti Palosaari's measurements show the R820T use ~300mA of 5v USB power while the E4000 devices use only ~170mA. You can cut the leads to the LED to drop usage ~10%.

The rtlsdr RTL2832U chips(pdf) use a phased locked loop based synthesizer to produce the local oscillator required by the quadrature mixer. The quadrature mixer produces a complex-baseband output where the signal spans from -bandwidth/2 to +bandwidth/2 and bandwidth is the analog bandwidth of the mixer output stages. (Datasheets, general refs: But what is the Fourier Transform? A visual introduction by 3Blue1Brown, Quadrature Signals: Complex, But Not Complicated by Richard Lyons) This is complex-sampled (I and Q) by the ADC. The Sigma-Delta ADC samples at some high rate but low precision. From this a 28.8 Msps stream at 8 bits is produced. That can be resampled inside the RTL2832U to present whatever sample rate is desired to the host PC. This resampled output can be up to 3.2 MS/s but 2.56 MS/s is the max recommended to avoid losing samples. The minimum resampled output is 0.5 MS/s. Check this reddit thread for caveats and details. The actual output is interleaved; so one byte I, then one byte Q with no header or metadata (timestamps). The samples themselves are unsigned and you subtract 127 (for rtlsdr it's: (x - 127.4f) * (1.0f / 128.0f)) from them to get their actual {-127,+127} value. You'll almost certainly still notice a stable spike around DC. It's from either the 1/f noise of the electronics or if it's a Zero-IF tuner (E4000) the LO beating with itself in the mixer.

Popular software

My favorite way to explore the spectrum is using rtl_power to do very wideband multi-day surveys. For general use SDR# is probably the best application for windows with secondary mono-based linux and Mac support. I normally use Gqrx but it requires GNU Radio dependencies. Luckily there are Linux and OS X native binaries packages with all dependencies (ie, gnuradio) these days. For doing diagnostic and low signal level work Linrad is full featured and fast. osmocom_fft comes with GNU Radio module gr-osmosdr and is the natural and best way to use gr-fosphor; a GPU accelerated display. multimode has a very full and configurable GUI (it works great with GPU accelerated displays like gr-fosphor). For command line and low power devices try keenerd's rtl_fm.

These sites maintain the best list of rtlsdr device supporting applications: https://sdr.osmocom.org/trac/wiki/rtl-sdr#KnownApps, https://sdr.osmocom.org/trac/wiki/GrOsmoSDR#KnownApps, and lately http://www.rtl-sdr.com/big-list-rtl-sdr-supported-software/

Assuming you're on linux, but applicable in general, do not use the OS DVB drivers. Those are for the DVB-T mode and not the debug mode that outputs raw samples. Linux 3.x kernel should check with "$ lsmod | grep dvb_usb_rtl28xxu" and if found at least "$ sudo modprobe -r dvb_usb_rtl28xxu" to unload it.

While the sampling bandwidth is only 2.56 MHz the frequency can be re-tuned up to ~40 times a second. With frequency hopping you can survey very large bandwidths. See tholin's annotated 24 hour rtl_power spectrogram.

This page is mostly just notes to myself on how to use rtlsdr's core applications, 3rd party stuff using librtlsdr and wrappers for it, and lots on using the gr-osmosdr source in GNU Radio and GNU Radio Companion. This isn't a "blog", don't read it sequentially, just search for terms of interest or use the topics menu. For realtime support on the same topics try irc.libera.chat IRC's ##rtlsdr and reddit's r/rtlsdr.

RTL-SDR Tuner Type	Frequency Range

Elonics E4000 (E4K)	54 - 2200 MHz (1100 MHz-1250 MHz gap)
Rafael Micro R820T	24 - 1766 MHz (>1500 MHz is bad w/o tuner cooling)
Rafael Micro R820T2	24 - 1766 MHz (>1500 MHz is bad w/o tuner cooling)
Rafael Micro R820T2 	13 - 1864 MHz (mutability's driver)
Fitipower FC0013	22 - 1100 MHz (FC0013B/C, FC0013G has seperate L band input)
Fitipower FC0012	22 - 948 MHz
FCI FC2580		146 - 308 MHz and 438 - 924 MHz

Only three tuners are very desirable at this time. The Elonics E4000 and the Raphael Micro R820T/R820T2. In general they are of equal performance but the sticks with R820T2 chips are easy to find, cheaper (~$10 USD), and they have a smaller DC spike due to the use of a non-zero intermediate frequency but must have cooling for the tuner to PLL lock above ~1500 MHz or so. The E4K is better for high end (>1.7GHz) while the R820T can tune down to 13 MHz without any hardware mods (mutability's driver). The tuners themselves are set up and retuned with I2C commands. E4000 tuners used to re-tune twice as fast as R820T tuners, but this was fixed in keenerd's experimental branch where R820T actually tune a tiny bit faster than the E4Ks. These changes were later adopted by the main rtlsdr.

For a detailed comparison of the E4000 vs R820T see the article, Some Measurements on E4000 and R820 Tuners: Image Rejection, Internal Signals, Sensitivity, Overload, 1 dB Compression, Intermodulation by HB9AJG in 2013.

R820T

• R820T_datasheet-Non_R-20111130_unlocked.pdf
• http://www.erlendervik.no/r820-reg.ods LB6MI (local)
• http://www.erlendervik.no/r820t-blocks.pdf (local)
• http://prkele.prk.tky.fi/~peltolt2/820T.xls (local)
• R820T2_Register_Description.pdf
• R820T_registers_attempt.xls
• old-dab tuner_r82xx.c register notes
• gat3way / r820tweak
• SDRSharp.R820T-master.zip
• R820T2 Breakout Board

E4000

• Elonics-E4000-Low-Power-CMOS-Multi-Band-Tunner-Datasheet.pdf
• e4000_refsch_rev4.pdf

As of Aug. 2014 a handful of people have found ways to extend the r820t frequency range as well. Initially thought to top out at 1700 MHZ the R820T driver has has re-written to tune from 22 to 1870(!) MHz. While efforts have been made to extend the lower range as well, with the PLL seeming to lock down to 8 MHz in some cases, this range turns out to be full of images and repeats of the higher frequency range. A later effort with the addition of driver tweaks to the RTL2832 downconverter pushed the low end down to ~15 MHz. The code is at https://github.com/mutability/rtl-sdr/.

After tejeez worked out the no-mod HF reception a couple people have noted that the tuners with fc0013 receive HF even better than the R820T board designs. So if you have one of those laying around you might want to try HF with it.

All of the dongles have significant frequency offsets from reality that can be measured and corrected at runtime. My ezcap with E4000 tuner has a frequency offset of about ~44 Khz or ~57 PPM from reality as determined by checking against a local 751 Mhz LTE cell using LTE Cell Scanner. Here's a plot of frequency offsets in PPM over a week. The major component of variation in time is ambient temperature. With the R820T tuner dongle after correctly for I have has a ~ -17 Khz offset at GSM frequencies or -35 ppm absolute after applying a 50 ppm initial error correction. When using kalibrate for this the initial frequency error is often too large and the FCCH peak might be outside the sampled 200 KHz bandwidth. This requires passing an initial ppm error parameter (from LTE scanner) -e . Another tool for checking frequency corrections is keenerd's version of rtl_test which uses (I think) ntp and system clock to estimate it rather than cell phone basestation broadcasts.

Also very cool is the MIT Haystack people switching to rtlsdr dongles (pdf) for their SRT and VSRT telescope designs, Use of DVB-T RTL2832U dongle with Rafael R820T tuner (pdf). The first of these characterizes the drift of the R820T clock and gain over time as well as a calibration routine.

As of 2015 there are a number of SDR-enthusiast targeting dongles produced with temperature controlled oscillators (TXCO) that run at less than 1 PPM with no start-up drift.

I recently (06-15-2014) found out from prog (of SDR# and airspy) that there are actually two different versions of the R820T tuner. The normal one and the R820T2. The T2 has different intermediate frequency filters allowing for wider IF bandwidths and apparently slightly better sensitivity (a few dB lower noise floor?). For rtlsdr dongles this difference in IF filter bandwidth usually doesn't matter much since all of them are larger than the RTL2832U's debug/SDR mode bandwidth of ~3 MHz. But there are certain situations where a larger tuner bandwidth is advantageous: such as when using Jowett's HF tuning mod. As of Sept. 2014 some of the new R820T2 have been showing up in Terratec "E4000 upgrade" model sticks. But don't count on it. I bought one from ebay seller "smallpartsbigdifference" which had a photo showing an R820T2 and it was just an R820T. Since ~2015 R820T2 have become far more available. Here's a pdf with the R820T2 Register Descriptions.

As of 2017-12-11 Rafael Micro has been sending out emails saying the R820T2 has been discontinued. Alternate versions of the series, not pin compatible, are the R836, R840, or R828D. I've already seen SDR-targeted dongles using the R828D.

As of March 2018 it's uncertain how many non-defect bin R820T2 tuners Rafael Micro has left but rtlsdrblog has said that if very large bulk orders could be made Rafael Micro might be willing to produce more.

In Feburary 2015 Leif sm5bsz (of linrad) relased a modified librtlsdr with changes to the rtlsdr R820T tuner code to allow for finer grained control over IF filter settings.

The IF filter which actually is a low pass filter and a high pass filter can be set for a bandwidth of 300 kHz. Dynamic range increases by something like 30 dB for the second next channel 400 kHz away. It is also possible to get some more improvement by changing the gain distribution.

Following this gat3way's patched gr-osmosdr and Vasili_ru's SDR# driver were released. gat3way made the IF filter width variable from within gqrx by presenting it as a gain value. Vasili's rtlsdr SDR# driver also moves the SDR# decimation normally applied during demodulation to the front of the IQ stream. This gives better dynamic range for the visual FFT but demodulated quality is not changed. So far this is all experimental but expect it to be brought mainline on both sides soon.

keenerd's experimental branch automatically set IF filter width based on sample rate but had not exposed them as manually set values.

TLeconte.github.io made some great plots of the R820T2 IF filter shapes in, "Playing with the Airspy R820T IF bandwidth". It should apply just the same for rtlsdr with changes.

In late 2013 Astrometra DVB-T2 dongles with the R828D tuner (pic) paired RTL2832U have begun to appear (2). The DVB-T2 stuff is done by a separate Panasonic chip on the same I2C bus. merbanan wrote a set of patches, rtl-astrometa, for librtlsdr has better support these tuners. The performance hasn't been characterized but it at least works for broadcast wide FM via SDR. steve|m's preliminary testing suggests bad performance in the form of the crystal for the DVB-T2 demodulator leaking fixed spurs 25 dB above noise floor in the IF at approximately 196 and -820 KHz. He was able to mitigate these with the hardware mod of removing the crystal for the DVB-T2 chip (ref). Official support was added to the rtl-sdr on Nov 5th while testing support was added on Nov 4th. In April 2017 u/strangerwithadvice on reddit made a quality post on the r/rtlsdr subreddit where he characterized the noise floor of an R828D dongle stock and with a number of modifications to reduce noise.

2012-08-22: The E4000 tuner datasheet has been released into the wild. Elonics-E4000-Low-Power-CMOS-Multi-Band-Tunner-Datasheet.pdf, but...

"All the ones that are documented in the DS are 'explained'in the driver header file ... And the rest, the datasheet call them "Ctrl2: Write 0x20 there" and no more details"

R820T original, support, etc

2012-09-07: Experimental support for dongles with the Rafael Micro R820T tuner that started appearing in May has been added to rtl-sdr source base by stevem. These tuners cover 24 MHz to 1766 MHz. They also don't have the DC spike caused by the I/Q imbalance since they use a different, non-zero, IF. On the other hand, they might have image aliasing due to being superheterodine receivers. See stevem's tuner comparisons. On 2012-09-20 the R820T datasheet was leaked to the ultra-cheap-sdr mailing list. The R820T2 Register Description pdf was provided by luigi tarenga to the ultra cheap sdr mailing list after he received it from RafaelMicro. The official range is 42-1002 Mhz with a 3.5 dB noise figure. On 2012-10-04 my order arrived. I'm liking this tuner very much since it actually works well, locking down to 24 Mhz or so *without* direct sampling mode. Here's a rough gnuplot spectral map of 24 to 1700 Mhz over 3 days I made with some custom perl and python scripts. Don't judge the r820t on the quality of that graph, it is just to show the range. You can see what I think is either front-end mixer filters not attenuating enough or actual intermodulation as RFI. I do almost no processing of the signal (ie, no IQ correction), don't clear the buffer between samples (LSB probably bad), and use a hacky way to display timeseries data in gluplot. Real SDR software like SDR# shows them to be equal or better in quality to E4ks.

stevem did gain measurement tests with a few dongles using some equipment he had to transmit a GSM FCCH peak, "which is a pure tone." This includes the E4000 and R820T tuners. In addition he measured the mixer, IF and LNA for the R820T.

Steve Markgraf of Osmocom has created an experimental software and hardware modification to receive 0~30Mhz(*) by using the 28.8 MHz RTL2832U ADCs for RF sampling and aliasing to do the conversion. In practice you only get DC-14.4MHz in the first Nyquist zone but the upper could be had by using a 14.4 MHz to 28.8 MHz bandpass filter. In the stereotypical ezcap boards you can test this by connecting an appropriately long wire antenna to the right side of capacitor 17 (on EzTV668 1.1, at least) that goes to pin 1 of the RTL2832U. That's the one by the dot on the chip surface. Apparently even pressing a wet finger onto the capacitor can pick up strong AM stations. This bypasses static protection among other things so there's a chance of destroying your dongle. For gr-osmosdr the parameter direct_samp=1 or direct_samp=2 gives you the two I or two Q inputs.

No hardware change, software mod direct sampling

It has recently become possible to use direct sampling with no hardware modifications at all. It is still very experimental and performance is bad. In Oct 2012 Anonofish on the r/rtlsdr subreddit had discovered the PLL would lock for a small ~ 3686.6 MHz - 3730 MHz range far outside the normal tuning range and there seemed to be signals there. In January 2014 ##rtlsdr IRC channel user tejeez figured out this bypassed the tuner (mixer leakage) and implemented a set of register settings (R820T IF frequency, IF filter bandwidths, r82xx_write_reg_mask(priv, 0x12, val, 0x08) replaced with r82xx_write_reg_mask(priv, 0x12, val|0x10, 0x18)) that would exploit this to enable HF reception. Shortly thereafter keenerd assembled everything into a relatively easy to use patch-set.

If you want to give HF listening a try with no risk keenerd has added these changes rtl_fm and rtl_power in his experimental rtlsdr repository. To use the no mode mode with rtl_ tools append the argument, "-E no-mod". To use the no-mod direct sampling in something that uses gr-osmosdr, like gqrx or GRC flowgraphs, add the following to the the "device string" parameters: ie "direct_samp=3". Plug your HF antenna into the normal connector, no hardware mods needed.

Differential input

I've been told my pin numbering doesn't correspond to the datasheets, so take that with salt. The relative positions are correct regardless of the numbering. The RTL2832 ADC differential input impedance is ~3,300 Ohm.

A number of people have tried to match the ADC's input impedance and both differential inputs by using baluns of various sorts. The datasheet seemed to say 200 Ohm so a lot of people (myself included) tried 4:1 baluns which did improve performance. But better matches can be found using the 1800 Ohm (36:1) Mini-circuits T36-1-KK81 with a 3900 Ohm resistor in parallel with the secondary to bring the RTL impedance down to 1800 Ohm (ref: G8JNJ).

Tom Berger (K1TRB) used multiple core materials with trifilar wire and performed tests using his N2PK virtual network analyzer on May 19th (2013).

Hams love type 43 ferrite, but for almost every application, there is a better choice. For broadband HF transformers Steward 35T is generally a better choice. Therefore, I wound a couple transformers and did the comparison. Type 43 and 35T Transformer Material Compared

For my tests with direct sampling mode I ordered a couple wideband transformers from coilcraft. The PWB-2-ALB and PWB-4-ALB to be specific. I sampled the PWB-4-ALB for free and ordered 4 of the PWB-2-ALB for ~$10 shipped. Both seem to work fine though I have no means of comparative testing.

If you're particularly interested in HF work then an upconverter would be better than the HF mod. With the mod there will be aliases(*) for any frequency over 14.4 Mhz (1/2 the 28.8 clock rate). So you'd want a 14 MHz lowpass for the low end or a 14-28 MHz bandpass for the high end. And probably other little idiosyncracies. A lot of people chose to just use an upconverter instead. KF7LE wrote up short summaries comparing 16 popular upconverters.

Another alternative is to make a diplexer so that you get both HF via direct sampling and VHF+/etc without any switches. G8JNJ has a detailed guide with annotated photos on how to build the appropriate circuit and modify the latest R820T2 type dongles with it. He reports being able to receive from 15 KHz to 1.8 GHz with this mod.

<Goatman> with a simple wire from pin 8 to 10 on the tuner pad
<Goatman> rtl_test reports all is well with direct sampling
<Goatman> ... Gqrx works fine btw with direct sampling even if no tuner is found

The most exciting development in rtlsdr that has happened recently are Juha Vierinen's discuss-gnuradio mailing list and blog posts about a simple and inexpensive method to distribute the clock signal from one dongle to multiple others for coherent operation.

"I recently came up with a trivial hack to build a receiver with multiple coherent channels using the RTL dongles. I do this basically by unsoldering the quartz clock on the slave units and cable the clock from the master RTL dongle to the input of the buffer amplifier (Xtal_in) in the slave units (I've attached some pictures)."

Since I've seen a lot of people asking, the dongles he used were Newsky TV28T v2 w/R820T tuners.

• $16 dual-channel coherent digital receiver
• Passive radar with $16 dual coherent channel rtlsdr dongle receiver

Max Manning also implemented a passive radar system using clock sharing rtlsdr. Ben Silverwood also did so as, " Low cost RTL-SDR passive multistatic DAB radar." an implementation in matlab. The youtube video description has links to photos of the setup.

Also, there's a Japanese seller with high precision SMD 28.8 MHz crystals. And an ebay seller with high precision 28.8 MHz oscillators for around ~$30 shipped.

Things again became exciting in June of 2014. Going beyond simple clock sharing and it's max of 3 dongles, YO3IIU put up a great post his build of a 4+ dongle RTL2832u based coherent multichannel receiver using a CDCLVC1310-EVM dev board from TI for clock distribution. His post shows the results of a gnuradio block he coded that does all the correlation math to align the samples from each receiver (which are out of step due to the way USB works). Unfortunately the software was never released.

steve|m's experiments were the first I heard about back in 2011. He used his 13MHz cell-phone clock as a reference for a PLL to generate 28.8MHz. He said he used 1v peak to peak. He also related it was possible to not even use the PLL and just the 13 MHz clock if w/E4000 tuners if you don't care about sample rate offset.

<steve|m> not really, just a picture and a short clip: http://steve-m.de/projects/rtl-sdr/osmocom_clocksource.webm http://steve-m.de/pictures/rtlsdr_external_clock.jpg
<steve|m> a motorola C139

The Green Bay Public Packet Radio guys have written up an interesting article on using 14.4 MHz temperature controlled crystal oscillators sent through a passive (two diode) frequency doubler followed by crystal filters made out of the old rtlsdr clock crystals to provide a low PPM error clock for rtlsdr devices. Since their mirror was missing images I cut them out of the Zine pdf and made a mirror here.

I first heard about the GBPPR article from patchvonbraun who implemented one and performed tests which he posted about on the Society for Amateur Radio Astronomy list. It turns out that even with a good distributed clock the 2x R820t rtlsdr dongles still have large phase error for some reason, see: Phase-coherence experiments with RTLSDR dongles and the photo post: Progress towards using RTLSDR dongles for interferometry.

Alex Paha has also done clock distribution but unlike the others he used E4000 tuner based receivers for his dual coherent receiver. He also seems to be using only half the I/Q pairs. This post is in Russian.

In October 2015 teejez uploaded his rtl_coherent code for maintaining multi-dongle coherence using external antenna switches to disconnect the antennas and connect all to a common noise source for correlation calibration. Here's a video of him using it to make a 3 dongle direction finder.

Each dither-disabled rtl-sdr is fed from the same reference clock. They still have unknown phase shifts and sampling time differences relative to each other. This is calibrated by disconnecting them from antennas and connecting every receiver to the same noise source. Cross correlation of the noise gives their time and phase differences so that it can be corrected. Currently the signal is received and processed in short blocks with each block starting with a burst of calibration noise.

As I understand it the switch chips are sa630 that "look" for dongle i2c traffic. There are controlled by two RC delay circuits so that every time you change frequency (causing i2c traffic) it disconnects antennas, waits for some time, feeds a pulse (just one edge from the logic chip) into all dongles, waits a bit more and connects the antennas back. You can see the evolution of his setup from this earlier prototype to this later prototype and finally the version used in his direction finder.

Every time you tune any two (or more) dongles to a new frequency there will be a tiny difference in the frequency each actually tuned to. The offset must corrected before trying to correlate them. If you don't it'll look like there's a constantly varying phase shift. Also don't forget to let the dongles warm up to equilibrium otherwise this additional temperature related frequency shift will cause changes even larger than relative tuning offset and you'll get the "random" phase shift again.

Multi-RTL

As of 2016 Piotr Krysik's "Multi-RTL" (github) has made maintaining coherence of multiple dongles accessible even to the amateur. His GNU Radio block handles all the complex details of keeping multiple rtlsdr coherent even when they're tuned to different frequencies and over re-tunes. It requires no external circuitry. You just have to distribute the clock signal with cable.

On the clock coherencey side Michele Bavaro's has explored, tweaked, and replaced, librtlsdr's pll setting code, intermediate frequency, and PLL dithering settings, such that the math, and results, work out cleaner. Using this modified driver he was able to minimize frequency setting errors and improve his GPS carrier following code. This is written up with code examples at his blog in, GNSS carrier phase, RTLSDR, and fractional PLLs (the necessary evil). Without dithering you can only tune to increments of 439.45 Hz. With dithering, you can tune to aproximately anything.

tejeez from the ##rtlsdr IRC relates that this can be done in r82xx_set_pll by changing r82xx_write_reg_mask(priv, 0x12, val, 0x08) to r82xx_write_reg_mask(priv, 0x12, val|0x10, 0x18). This has been implemented as an option in rtl_sdr, '-N', in keenerd's experimental branch.

Misc

In the absence of any useful information about the RTL2832U clock here's some information about the R820T's clock system.

Crystal parallel capacitors are recommended when a default crystal frequency of 16 MHz is implemented. Please contact Rafael Micro application engineering for crystal parallel capacitors using other crystal frequencies. For cost sensitive project, the R820T can share crystal with backend demodulators or baseband ICs to reduce component count. The recommended reference design for crystal loading capacitors and share crystal is shown as below.

Noise, shielding, cables, and why is that FM signal there?!

When you see something weird, like commercial FM broadcasts at 27 MHz, what you are seeing incomplete filtering of mixing products. It's the harmonics of the square wave driving the mixers combined with insufficient rf filtering to suppress the response. You can tell if it is a local oscillator mixer harmonic leakage by sweeping the frequency and seeing how fast the ghost signal moves relative to this; look for linear relationships (ie, 2x the speed, 1/4 the speed, in-depth reference). Sometimes local signals can be powerful (ie, pagers) or close enough to make the preamplifier behave non-linearly resulting in intermodulation. For this kind of RFI turning down the gain helps.

Another way to differentiate RFI from intentionally broadcast radio signals is the sharpness of the edge of the transmission in the spectrogram. If the power drops off very sharply at an edge it's an indication of the strong filterine required of operators to confine their spectral power to only their licensed band.

The tuners all have a certain amount of intrinsic noise too. keenerd had done tests with an R820T rtlsdr terminated to a resistor inside of a metal box. For these tests rtl_power gain was set to max (49.6dB) and a frequency sweep was done through the entire tuner range, r820t Background Noise. The 28.8 MHz spikes from the clock frequency can be seen among other abberations.

But not everything is a ghost from hardware design problems. Depending on your computer setup and local electronics there could be a lot of "real noise"; LCD monitors are a common culprit for VHF noise spikes distributed across wide ranges. It is best to shield and put ferrites on everything if you can.

To solve the commercial FM mixing problems an FM trap can be used. Commercial ones work fine typically. But for non-commercial FM RFI like emergency services and pagers custom filters must be made or ordered. Adam-9A4QV has a detailed write-up on making FM trap with a very high upper passband (all the way to 1.7 GHz) with links to design for other low VHF bands. tejeez shared his VHF bandstop design on IRC. Like Adam's it has the unique feature of not also wiping out harmonics of the FM band: fm-notch.jpg fm-notch_schematic.png. This means you can use it and still do wideband frequency hopping (unlike, say, a 1/4th wave coaxial stub). For more information on this general type of coaxial cable notch filter check out Ed Loranger's write up on VHF Notch filters (photo). For my powerful 461 MHz RFI that can be received without an antenna I use a custom 3 cavity notch filter from Par Electronics.

Acinonyx describes one way to doing this using a single strip of aluminum tape combined with a spring to connect it to the dongle ground. Akos Czermann at the sdrformariners blog made a somewhat confusing but definitely empirical comparison of noise levels compared to different hardware mods like disconnecting the USB ground from the rtlsdr ground. Quite a few people have had success with that and scotch tape around the USB connector works to test it.

Some others bond the enclosure to both the antenna and the USB shield and this works reliably and well.

Martin from g8jnj.net finds the most effective mod to reduce USB and DC-converter noise is shielding the antenna input area with metal soldered to the pcb ground, "The noise seems to be coupled directly between components on the topside of the PCB." You can find it if you scroll about halfway down the page linked.

Additional noise comes from the switching power supply in the RTL2832U that runs at 1.024MHz. This drops the supplied 3.3v down to the 1.2v needed for internal use. ttrftech has successfully disconnected this switching supply replaced it with 3 diodes to drop the 5v line down to ~1.2v. In the example linked above ttrftech uses power form the far side of the board but the eeprom's power rail would also work. This decreases spurs in HF significantly. It will increase power usage though; something to watch out for when R820T dongles start out at ~300mA a piece.

Laidukas's "Mods and performance of R820T2 based RTL SDR receiver covers replacing all the power rails with external linear regulators, increasing the amount of bypass capacitance on power lines, adding extra chip filtering for the USB 5v line, cutting off the IR receiver part of the PCB, wiring in a TCXO 28.8MHz oscillator, creating a shield with kapton tape and copper foil soldered extensively to the PCB ground, and a new heavy metal case and connectors.

To reduce signal loss over long distances and get away from computer RFI I like to run long USB *active* extension cable with hubs at the end and ferrites added instead of coaxial cable. Around this USB cable I clip on 5 or 6 ferrites at each end. Active extension/repeater USB2 cables of up to 25m in length can be used.

Entering Data Consumer.
Entering Radio Event Consumer.
Found 1 device(s):
  0:  Realtek, RTL2838UHIDIR, SN: 00000001

Using device 0: Generic RTL2832U OEM
Found Rafael Micro R820T tuner
Sampling at 256000 S/s.
Tuner gain set to automatic.
write tuner register entry
0000 02 1A 64 02 14 D8 00 00 00 00 00 02 1C CE E4 90 
0010 40 00 F0 90 40 02 F0 90 20 FB E0 54 60 24 C0 70 
0020 03 02 06 F7 24 40 60 03 02 0A 7C 90 20 FA E0 B4 
0030 0C 00 40 03 02 0A 7C 90 00 3E F8 28 28 73 02 04 
0040 D9 02 06 7A 02 0A 7C 02 05 7A 02 0A 7C 02 03 52 
0050 02 00 62 02 0A 7C 02 05 6F 02 03 A4 02 04 20 02 
0060 04 2B 90 20 FC E0 F5 23 A3 E0 F5 24 30 01 08 75 
0070 27 00 75 28 22 80 06 75 27 00 75 28 19 90 20 F8 
0080 E0 24 FE 60 38 14 70 03 02 01 61 24 FD 70 03 02 
0090 02 87 14 70 03 02 02 A9 24 06 60 03 02 03 4F E5 
00A0 09 C3 95 24 50 06 AF 09 7E 00 80 04 AE 23 AF 24 
00B0 8E 23 8F 24 7B 00 7A 00 79 09 02 03 4A C3 E5 28 
00C0 95 24 E5 27 94 00 50 06 AE 27 AF 28 80 04 AE 23 
00D0 AF 24 8E 23 8F 24 90 20 14 A3 A3 A3 E0 54 01 FF 
00E0 E4 FE FC EF 60 2C E4 90 40 01 F0 90 40 01 E0 C3 
00F0 95 24 E4 95 23 50 47 E0 FF 90 0D E2 93 FE 74 90 
0100 2F F5 82 E4 34 40 F5 83 EE F0 90 40 01 E0 04 F0 
0110 80 D9 E4 90 40 01 F0 90 40 01 E0 C3 95 24 E4 95 
0120 23 50 1B E0 FF 90 0E 1A 93 FE 74 90 2F F5 82 E4 
0130 34 40 F5 83 EE F0 90 40 01 E0 04 F0 80 D9 90 40 
0140 92 E5 28 F0 E5 27 A3 F0 30 01 04 A3 74 02 F0 30 
0150 00 06 90 40 97 74 A0 F0 7B 01 7A 40 79 90 02 03 
0160 4A 90 20 F9 E0 B4 07 00 40 03 02 06 B5 90 01 74 
0170 F8 28 28 73 02 01 89 02 01 AB 02 01 CC 02 02 00 
0180 02 02 21 02 02 43 02 02 65 90 0E 04 E4 93 FE C3 
0190 95 24 50 06 EE FF 7E 00 80 04 AE 23 AF 24 8E 23 
01A0 8F 24 7B FF 7A 0E 79 04 02 03 4A 90 40 10 E0 FE 
01B0 C3 95 24 50 06 EE FF 7E 00 80 04 AE 23 AF 24 8E 
01C0 23 8F 24 7B 01 7A 40 79 10 02 03 4A 90 40 10 E0 
01D0 24 10 F5 82 E4 34 40 F5 83 E0 FE C3 95 24 50 06 
01E0 EE FF 7E 00 80 04 AE 23 AF 24 8E 23 8F 24 90 40 
01F0 10 E0 7E 00 24 10 F9 EE 34 40 FA 7B 01 02 03 4A 
0200 90 40 60 E0 FE C3 95 24 50 06 EE FF 7E 00 80 04 
0210 AE 23 AF 24 8E 23 8F 24 7B 01 7A 40 79 60 02 03 
0220 4A 90 0E 86 E4 93 FE C3 95 24 50 06 EE FF 7E 00 
0230 80 04 AE 23 AF 24 8E 23 8F 24 7B FF 7A 0E 79 86 
0240 02 03 4A 90 0E A6 E4 93 FE C3 95 24 50 06 EE FF 
0250 7E 00 80 04 AE 23 AF 24 8E 23 8F 24 7B FF 7A 0E 
0260 79 A6 02 03 4A 90 0E CC E4 93 FE C3 95 24 50 06 
0270 EE FF 7E 00 80 04 AE 23 AF 24 8E 23 8F 24 7B FF 
0280 7A 0E 79 CC 02 03 4A 90 0E F0 E4 93 FE C3 95 24 
0290 50 06 EE FF 7E 00 80 04 AE 23 AF 24 8E 23 8F 24 
02A0 7B FF 7A 0E 79 F0 02 03 4A C3 E5 28 95 24 E5 27 
02B0 94 00 50 06 AE 27 AF 28 80 04 AE 23 AF 24 8E 23 
02C0 8F 24 90 20 14 A3 A3 A3 E0 54 01 FF E4 FE FC EF 
02D0 60 2C E4 90 40 01 F0 90 40 01 E0 C3 95 24 E4 95 
02E0 23 50 47 E0 FF 90 0F 44 93 FE 74 90 2F F5 82 E4 
02F0 34 40 F5 83 EE F0 90 40 01 E0 04 F0 80 D9 E4 90 
0300 40 01 F0 90 40 01 E0 C3 95 24 E4 95 23 50 1B E0 
0310 FF 90 0F 0C 93 FE 74 90 2F F5 82 E4 34 40 F5 83 
0320 EE F0 90 40 01 E0 04 F0 80 D9 90 40 92 E5 28 F0 
0330 E5 27 A3 F0 30 01 04 A3 74 02 F0 30 00 06 90 40 
0340 97 74 A0 F0 7B 01 7A 40 79 90 AD 24 02 05 77 02 
0350 06 B5 90 20 F8 E0 F5 23 A3 E0 F5 24 90 21 08 12 
0360 12 0B 00 00 00 02 75 40 00 75 41 96 90 21 0C A3 
0370 A3 A3 E0 54 80 FF E4 FE FD FC FB FA F9 F8 C3 12 
0380 11 AB 60 0D AE 23 AF 24 E4 FC FD 90 20 18 02 09 
0390 74 90 21 08 12 12 0B 00 00 00 02 E5 41 45 40 70 
03A0 CB 02 06 B5 90 20 F9 E0 14 60 09 04 70 6F E4 F5 
03B0 44 02 08 02 75 44 01 90 21 48 12 12 0B 00 00 00 
03C0 20 90 21 48 E0 FC A3 E0 FD A3 E0 FE A3 E0 54 DF 
03D0 FF EC 90 21 48 12 11 FF 90 20 14 A3 A3 A3 E0 54 
03E0 01 FF E4 FE FD FC EF 90 21 58 60 09 12 12 0B 00 
03F0 00 02 00 80 07 12 12 0B 00 00 00 40 90 21 44 12 
0400 12 0B 00 00 00 D1 90 21 4C 12 12 0B FF FF FF FF 
0410 90 21 50 12 12 0B FF FF FF FF 02 08 02 02 06 B5 
0420 7B 00 7A 00 79 3F 7D 01 02 05 77 90 20 F9 E0 75 
0430 23 00 F5 24 F5 3F 45 23 60 0B E5 24 64 01 45 23 
0440 60 03 02 04 D6 90 21 48 12 12 0B 00 00 00 20 90 
0450 21 48 E0 FC A3 E0 FD A3 E0 FE A3 E0 54 DF FF EC 
0460 90 21 48 12 11 FF E5 24 45 23 70 30 90 20 14 A3 
0470 A3 A3 E0 54 01 FF E4 FE FD FC EF 90 21 58 60 09 
0480 12 12 0B 00 00 02 00 80 07 12 12 0B 00 00 00 40 
0490 90 21 44 12 12 0B 00 00 00 D1 80 23 90 20 14 A3 
04A0 A3 A3 E0 54 01 FF E4 FE FD FC EF 90 21 58 12 12 
04B0 0B 00 00 03 AC 90 21 44 12 12 0B 00 00 00 B1 90 
04C0 21 4C 12 12 0B FF FF FF FF 90 21 50 12 12 0B FF 
04D0 FF FF FF 02 08 02 02 06 B5 E4 F5 27 F5 28 90 20 
04E0 FE E0 F5 23 A3 E0 F5 24 90 20 FB E0 54 1F 14 60 
04F0 3B 14 60 42 24 02 70 74 E5 24 45 23 70 2B 90 20 
0500 10 A3 A3 A3 E0 54 04 FF E4 FD FC EF 60 06 75 27 
0510 00 75 28 02 AF 28 AE 27 12 1C FD 8E 27 8F 28 7B 
0520 00 7A 00 79 27 7D 02 80 4E 02 06 B5 7B 00 7A 00 
0530 79 27 7D 02 80 41 E5 24 64 81 45 23 70 2B 90 21 
0540 48 A3 A3 A3 E0 54 10 FF E4 FD FC EF 60 06 75 27 
0550 00 75 28 01 AF 28 AE 27 12 1C FD 8E 27 8F 28 7B 
0560 00 7A 00 79 27 7D 02 80 0E 02 06 B5 02 06 B5 7B 
0570 00 7A 00 79 44 7D 01 02 19 D3 90 20 FB E0 54 1F 
0580 14 70 03 02 06 78 14 70 03 02 06 56 24 02 60 03 
0590 02 06 78 90 20 F9 E0 24 FE 60 26 04 60 03 02 06 
05A0 54 30 00 1A 90 20 10 E0 FC A3 E0 FD A3 E0 FE A3 
05B0 E0 44 04 FF EC 90 20 10 12 11 FF 02 08 02 02 06 
05C0 B5 90 20 FF E0 60 03 02 06 52 90 20 FE E0 75 23 
05D0 00 F5 24 C3 94 01 E5 23 94 00 40 74 E5 24 94 05 
05E0 E5 23 94 00 50 6A 90 21 08 12 12 0B 00 00 00 02 
05F0 90 21 0C A3 A3 A3 E0 54 80 FF E4 FE FD FC EF 60 
0600 EF E5 23 70 49 E5 24 24 FE 60 16 14 60 1F 14 60 
0610 28 24 03 70 39 90 20 1C 12 12 0B 00 00 00 02 80 
0620 2D 90 20 1C 12 12 0B 00 00 00 03 80 21 90 20 1C 
0630 12 12 0B 00 00 00 01 80 15 7B FF 7A 0F 79 6A 7D 
0640 35 12 19 D3 90 20 1C 12 12 0B 00 00 00 04 80 FE 
0650 80 63 80 61 80 5F 90 20 F9 E0 70 1A 90 20 FF E0 
0660 B4 81 11 90 21 48 E0 FC A3 E0 FD A3 E0 FE A3 E0 
0670 44 10 80 63 80 3F 80 3D 80 3B 90 20 FB E0 14 60 
0680 34 14 60 37 24 02 70 69 90 20 F9 E0 B4 01 16 90 
0690 20 10 E0 FC A3 E0 FD A3 E0 FE A3 E0 54 FB FF EC 
06A0 90 20 10 80 37 90 20 F9 E0 90 21 08 B4 02 03 02 
06B0 0A 29 02 0A 75 90 21 08 02 0A 75 90 20 F9 E0 70 
06C0 2A 90 20 FF E0 B4 81 1D 90 21 48 E0 FC A3 E0 FD 
06D0 A3 E0 FE A3 E0 54 EF FF EC 90 21 48 12 11 FF 90 
06E0 21 08 02 0A 29 90 21 08 02 0A 75 90 21 08 02 0A 
06F0 75 90 21 08 02 0A 75 90 20 FC E0 F5 23 A3 E0 F5 
0700 24 A3 E0 B4 08 00 40 03 02 0A 72 90 07 12 F8 28 
0710 28 73 02 07 2A 02 09 25 02 09 25 02 07 88 02 08 
0720 A1 02 09 1F 02 07 6B 02 0A 3C 90 20 F9 E0 F5 22 
0730 90 20 FF E0 54 0F 90 40 90 F0 E0 65 08 60 49 75 
0740 33 01 75 34 40 75 35 90 E4 F5 36 7B 01 FD AF 22 
0750 12 12 7C 40 0E 90 21 08 12 12 0B 00 00 00 10 75 
0760 08 FF 22 90 40 90 E0 F5 08 80 1D D3 E5 24 94 10 
0770 E5 23 94 00 40 06 90 21 08 02 0A 75 90 20 FE E0 
0780 60 06 90 40 00 74 01 F0 90 20 F9 E0 F5 22 90 20 
0790 F8 E0 75 27 00 F5 28 90 20 FF E0 20 E4 76 75 40 
07A0 00 75 41 64 90 21 0C A3 A3 A3 E0 54 02 FF E4 FE 
07B0 FD FC EF 60 53 D3 E5 24 94 40 E5 23 94 00 40 04 
07C0 7F 40 80 04 AE 23 AF 24 8E 25 8F 26 C3 E5 24 95 
07D0 26 F5 24 E5 23 95 25 F5 23 AD 28 AB 26 90 40 00 
07E0 E0 F5 2C AF 22 12 17 BE 40 06 90 21 08 02 0A 75 
07F0 E5 26 25 28 F5 28 E5 25 35 27 F5 27 E5 24 45 23 
0800 70 06 90 21 08 02 0A 29 E5 41 45 40 70 96 90 21 
0810 08 02 0A 75 90 21 0C A3 A3 A3 E0 54 02 FF E4 FE 
0820 FD FC EF 70 6D 90 21 20 E0 FC A3 E0 FD A3 E0 FE 
0830 A3 E0 FF EE 54 07 FE 8E 25 8F 26 E5 26 65 24 70 
0840 04 E5 25 65 23 60 06 90 21 08 02 0A 75 AD 28 AB 
0850 26 90 40 00 E0 F5 2C AF 22 12 19 35 40 06 90 21 
0860 08 02 0A 75 E5 26 25 28 F5 28 E5 25 35 27 F5 27 
0870 C3 E5 24 95 26 F5 24 E5 23 95 25 F5 23 45 24 60 
0880 0B C3 E5 26 94 40 E5 25 94 00 50 06 90 21 08 02 
0890 0A 29 E5 41 45 40 60 03 02 08 14 90 21 08 02 0A 
08A0 75 90 20 F8 E0 F5 27 A3 E0 F5 28 90 20 FF E0 20 
08B0 E4 67 75 40 00 75 41 64 90 21 0C A3 A3 A3 E0 54 
08C0 02 FF E4 FE FD FC EF 60 44 D3 E5 24 94 40 E5 23 
08D0 94 00 40 04 7F 40 80 04 AE 23 AF 24 8E 25 8F 26 
08E0 C3 E5 24 95 26 F5 24 E5 23 95 25 F5 23 AA 27 A9 
08F0 28 7B FF AD 26 12 19 D3 E5 26 25 28 F5 28 E5 25 
0900 35 27 F5 27 E5 24 45 23 70 03 02 0A 7C E5 41 45 
0910 40 70 A5 90 21 08 02 0A 75 90 21 08 02 0A 75 90 
0920 21 08 02 0A 75 90 20 F8 E0 F5 27 A3 E0 F5 28 90 
0930 20 FF E0 54 0F 90 40 02 F0 75 40 00 75 41 64 90 
0940 20 FF E0 30 E4 03 02 09 C8 90 21 0C A3 A3 A3 E0 
0950 54 02 FF E4 FE FD FC EF 60 62 E5 24 45 23 70 17 
0960 90 21 08 E0 FC A3 E0 FD A3 E0 FE A3 E0 44 02 FF 
0970 EC 90 21 08 02 11 FF D3 E5 24 94 40 E5 23 94 00 
0980 40 06 7E 00 7F 40 80 04 AE 23 AF 24 8E 25 8F 26 
0990 C3 E5 24 95 26 F5 24 E5 23 95 25 F5 23 AA 27 A9 
09A0 28 7B 01 EF FD 7C 00 90 40 02 E0 F5 2E 12 13 C4 
09B0 E5 26 25 28 F5 28 E5 25 35 27 F5 27 E5 41 45 40 
09C0 70 87 90 21 08 02 0A 75 90 21 0C A3 A3 A3 E0 54 
09D0 02 FF E4 FE FD FC EF 70 58 90 21 20 A3 A3 E0 FE 
09E0 A3 E0 FF EE 54 07 FE 8E 25 8F 26 AA 27 A9 28 7B 
09F0 01 90 40 02 E0 F5 2E AD 26 AC 25 12 15 DB E5 26 
0A00 25 28 F5 28 E5 25 35 27 F5 27 C3 E5 24 95 26 F5 
0A10 24 E5 23 95 25 F5 23 45 24 60 0B C3 E5 26 94 40 
0A20 E5 25 94 00 50 0B 90 21 08 12 12 0B 00 00 00 02 
0A30 22 E5 41 45 40 70 91 90 21 08 80 39 90 20 F8 E0 
0A40 F5 40 A3 E0 F5 41 90 20 FF E0 30 E4 20 90 20 10 
0A50 E0 FC A3 E0 FD A3 E0 FE A3 E0 54 FE FF EC 90 20 
0A60 10 12 11 FF E5 41 45 40 70 FA 02 18 95 90 21 08 
0A70 80 03 90 21 08 12 12 0B 00 00 00 10 22 75 22 01 
0A80 75 23 40 75 24 90 E4 F5 26 F5 2F F5 2C E5 2C 90 
0A90 0D D0 93 FF 74 09 25 2C F8 A6 07 05 2C E5 2C B4 
0AA0 12 EB E4 F5 25 85 22 34 85 23 35 85 24 36 F5 37 
0AB0 7B 0E 12 0F B6 40 03 02 0D 52 AB 22 AA 23 A9 24 
0AC0 12 11 31 64 12 60 0D 90 00 01 12 11 4A 64 34 60 
0AD0 03 02 0B A5 90 30 00 E0 F5 28 44 10 F0 90 30 07 
0AE0 E0 F5 28 54 EF F0 90 30 02 E0 F5 28 44 10 F0 90 
0AF0 00 02 12 11 4A 64 56 70 25 AB 22 AA 23 A9 24 90 
0B00 00 03 12 11 4A B4 78 16 90 00 04 12 11 4A FE 90 
0B10 00 05 12 11 4A FD EE F5 2A ED F5 2B 80 06 75 2A 
0B20 80 75 2B 0D 7D 00 7C 20 E4 FF FE 12 1B 5A AD 07 
0B30 AC 06 E5 2B B5 05 0E E5 2A B5 04 09 90 30 02 E0 
0B40 F5 28 54 EF F0 90 30 02 E0 F5 28 44 01 F0 AB 22 
0B50 AA 23 A9 24 90 00 06 12 11 4A 64 12 60 0A 90 00 
0B60 07 12 11 4A 64 34 70 28 AB 22 AA 23 A9 24 90 00 
0B70 08 12 11 4A FB EC F5 2D ED F5 2E AF 03 7D 09 75 
0B80 33 00 75 34 00 75 35 2D E4 F5 36 7B 02 12 12 7C 
0B90 75 40 00 75 41 02 E5 41 45 40 70 FA 90 30 02 E0 
0BA0 F5 28 54 FE F0 AB 22 AA 23 A9 24 12 11 31 64 28 
0BB0 60 03 02 0D 52 90 00 01 12 11 4A 64 32 60 03 02 
0BC0 0D 52 75 22 01 75 23 40 75 24 92 E4 F5 2C AB 22 
0BD0 AA 23 A9 24 85 2C 82 75 83 00 12 11 4A FF 74 11 
0BE0 25 2C F8 A6 07 05 2C E5 2C B4 04 E2 90 40 96 E0 
0BF0 B4 A5 08 75 19 03 75 2F 01 80 05 E4 F5 19 F5 2F 
0C00 75 22 01 75 23 40 75 24 90 75 25 09 90 40 97 E0 
0C10 F5 20 E4 F5 2C E5 26 25 25 F5 25 85 22 34 85 23 
0C20 35 85 24 36 E4 F5 37 7B 01 12 0F B6 40 03 02 0D 
0C30 52 AB 22 AA 23 A9 24 12 11 31 25 26 F5 26 05 2C 
0C40 E5 2C C3 94 02 40 CE E5 26 D3 94 46 40 03 02 0D 
0C50 52 75 25 09 85 26 27 E5 27 D3 94 00 40 28 E5 27 
0C60 D3 94 10 40 04 7F 10 80 02 AF 27 12 0F 9F 40 03 
0C70 02 0D 52 E5 29 25 25 F5 25 E5 29 25 24 F5 24 E4 
0C80 35 23 F5 23 80 D1 75 22 01 75 23 40 75 24 90 E4 
0C90 F5 2C E5 2C C3 95 26 50 21 AB 22 AA 23 A9 24 85 
0CA0 2C 82 75 83 00 12 11 4A FF 74 10 25 2C F5 82 E4 
0CB0 34 40 F5 83 EF F0 05 2C 80 D8 E5 2F 70 03 02 0D 
0CC0 CF E5 26 24 09 F5 25 85 22 34 85 23 35 85 24 36 
0CD0 E4 F5 37 7B 01 12 0F B6 50 78 AB 22 AA 23 A9 24 
0CE0 12 11 31 F5 26 E5 26 D3 94 28 50 66 85 26 27 E5 
0CF0 27 D3 94 00 40 25 E5 27 D3 94 10 40 04 7F 10 80 
0D00 02 AF 27 12 0F 9F 50 4A E5 29 25 25 F5 25 E5 29 
0D10 25 24 F5 24 E4 35 23 F5 23 80 D4 75 22 01 75 23 
0D20 40 75 24 90 E4 F5 2C E5 2C C3 95 26 40 03 02 0D 
0D30 CF AB 22 AA 23 A9 24 85 2C 82 75 83 00 12 11 4A 
0D40 FF 74 60 25 2C F5 82 E4 34 40 F5 83 EF F0 05 2C 
0D50 80 D5 E4 F5 2C E5 2C 90 0E 62 93 FF 74 60 25 2C 
0D60 F5 82 E4 34 40 F5 83 EF F0 05 2C E5 2C B4 24 E5 
0D70 90 0E 40 E4 93 F5 26 E4 F5 25 E5 25 C3 95 26 50 
0D80 18 E5 25 90 0E 40 93 FF 74 10 25 25 F5 82 E4 34 
0D90 40 F5 83 EF F0 05 25 80 E1 90 0E 50 E4 93 F5 26 
0DA0 E4 F5 2C E5 2C C3 95 26 50 21 E5 2C 90 0E 50 93 
0DB0 FF E5 2C FD E5 25 2D FD E4 33 FC 74 10 2D F5 82 
0DC0 74 40 3C F5 83 EF F0 05 2C 80 D8 D2 02 D2 00 22 
0DD0 12 01 00 02 00 00 00 40 DA 0B 32 28 00 01 01 02 
0DE0 03 01 09 02 22 00 01 01 04 80 FA 09 04 00 00 01 
0DF0 FF FF FF 05 07 05 81 02 00 02 00 09 04 01 00 00 
0E00 FF FF FF 05 04 03 09 04 12 01 00 02 00 00 00 40 
0E10 DA 0B 32 28 00 01 01 02 03 01 09 02 22 00 01 01 
0E20 04 80 FA 09 04 00 00 01 FF FF FF 05 07 05 81 02 
0E30 40 00 01 09 04 01 00 00 FF FF FF 05 04 03 09 04 
0E40 10 03 47 00 65 00 6E 00 65 00 72 00 69 00 63 00 
0E50 12 03 52 00 54 00 4C 00 32 00 38 00 33 00 32 00 
0E60 55 00 24 03 37 00 37 00 37 00 37 00 31 00 31 00 
0E70 31 00 31 00 31 00 35 00 33 00 37 00 30 00 35 00 
0E80 37 00 30 00 30 00 20 03 55 00 53 00 42 00 32 00 
0E90 2E 00 30 00 2D 00 42 00 75 00 6C 00 6B 00 26 00 
0EA0 49 00 73 00 6F 00 26 03 42 00 75 00 6C 00 6B 00 
0EB0 2D 00 49 00 6E 00 2C 00 20 00 49 00 6E 00 74 00 
0EC0 65 00 72 00 66 00 61 00 63 00 65 00 24 03 49 00 
0ED0 73 00 6F 00 2D 00 49 00 6E 00 2C 00 20 00 49 00 
0EE0 6E 00 74 00 65 00 72 00 66 00 61 00 63 00 65 00 
0EF0 0A 06 00 02 00 00 00 40 02 00 12 01 00 02 00 00 
0F00 00 40 DA 0B 32 28 01 00 01 02 03 01 09 07 22 00 
0F10 01 01 04 80 FA 09 04 00 00 01 FF FF FF 05 07 05 
0F20 81 02 00 02 00 09 04 01 00 00 FF FF FF 05 04 03 
0F30 09 04 12 01 00 02 00 00 00 40 DA 0B 32 28 00 01 
0F40 01 02 03 01 09 07 22 00 01 01 04 80 FA 09 04 00 
0F50 00 01 FF FF FF 05 07 05 81 02 40 00 01 09 04 01 
0F60 00 00 FF FF FF 05 04 03 09 04 00 00 00 00 00 00 
0F70 00 00 00 AA AA AA AA AA AA AA AA EE EE EE EE EE 
0F80 EE EE EE FE FF FF FF FF FF FF FF FF FF FF FF 7F 
0F90 BF DF EF F7 FB FD FC 7E BF DF EF F7 FB FD 7E 8F 
0FA0 29 C3 E5 27 95 29 F5 27 85 22 34 85 23 35 85 24 
0FB0 36 E4 F5 37 AB 29 AD 25 7F A0 8F 31 8D 32 8B 33 
0FC0 AF 33 EF 33 95 E0 FE EF 24 FF FF EE 34 FF FE 33 
0FD0 95 E0 8F 3B 8E 3A F5 39 F5 38 75 3C 05 FD AC 38 
0FE0 78 19 12 11 BC 8F 3B 8E 3A 8D 39 8C 38 90 30 44 
0FF0 E0 FC A3 E0 FD A3 E0 FE A3 E0 FF EC 44 80 FC 90 
1000 30 44 12 11 FF 90 30 44 E0 FC A3 A3 A3 E4 FF FE 
1010 FD EC 54 80 FC E4 FB FA F9 78 80 C3 12 11 AB 60 
1020 E4 E5 37 70 4B E5 31 54 FE FF 33 95 E0 FE FD FC 
1030 90 30 50 12 11 FF AF 32 EF 33 95 E0 FE FD FC 90 
1040 30 50 12 11 FF E5 31 44 01 FF 33 95 E0 FE FD FC 
1050 90 30 50 12 11 FF E5 3B 44 28 FF E5 3A FE E5 39 
1060 FD E5 38 FC 90 30 44 12 11 FF E5 3B 44 28 80 21 
1070 E5 31 44 01 FF 33 95 E0 FE FD FC 90 30 50 12 11 
1080 FF AF 3B AE 3A AD 39 AC 38 90 30 44 12 11 FF E5 
1090 3B FF E5 3A FE E5 39 FD E5 38 44 40 FC 90 30 44 
10A0 12 11 FF 90 30 44 E0 FC A3 A3 A3 E4 FF FE FD EC 
10B0 54 40 FC E4 FB FA F9 78 40 C3 12 11 AB 60 E4 90 
10C0 30 4C A3 A3 A3 E0 54 04 FF E4 FE FD FC 7B 04 FA 
10D0 F9 F8 C3 12 11 AB 70 0C 90 30 4C 12 12 0B 00 00 
10E0 00 04 80 3F 90 30 4C 12 12 0B 00 00 00 02 E4 F5 
10F0 3D AF 33 EF 33 95 E0 FE C3 E5 3D 9F EE 64 80 F8 
1100 74 80 98 50 1C 90 30 50 A3 A3 A3 E0 FF E4 AB 34 
1110 AA 35 A9 36 85 3D 82 F5 83 EF 12 11 89 05 3D 80 
1120 D0 D3 22 15 3C E5 3C D3 94 00 40 03 02 0F ED C3 
1130 22 BB 01 06 89 82 8A 83 E0 22 50 02 E7 22 BB FE 
1140 02 E3 22 89 82 8A 83 E4 93 22 BB 01 0C E5 82 29 
1150 F5 82 E5 83 3A F5 83 E0 22 50 06 E9 25 82 F8 E6 
1160 22 BB FE 06 E9 25 82 F8 E2 22 E5 82 29 F5 82 E5 
1170 83 3A F5 83 E4 93 22 BB 01 06 89 82 8A 83 F0 22 
1180 50 02 F7 22 BB FE 01 F3 22 F8 BB 01 0D E5 82 29 
1190 F5 82 E5 83 3A F5 83 E8 F0 22 50 06 E9 25 82 C8 
11A0 F6 22 BB FE 05 E9 25 82 C8 F2 22 EB 9F F5 F0 EA 
11B0 9E 42 F0 E9 9D 42 F0 E8 9C 45 F0 22 E8 60 0F EF 
11C0 C3 33 FF EE 33 FE ED 33 FD EC 33 FC D8 F1 22 BB 
11D0 01 0D E5 82 29 F5 82 E5 83 3A F5 83 02 12 54 50 
11E0 07 E9 25 82 F8 02 12 48 BB FE 07 E9 25 82 F8 02 
11F0 12 60 E5 82 29 F5 82 E5 83 3A F5 83 02 12 6C EC 
1200 F0 A3 ED F0 A3 EE F0 A3 EF F0 22 A8 82 85 83 F0 
1210 D0 83 D0 82 12 12 22 12 12 22 12 12 22 12 12 22 
1220 E4 73 E4 93 A3 C5 83 C5 F0 C5 83 C8 C5 82 C8 F0 
1230 A3 C5 83 C5 F0 C5 83 C8 C5 82 C8 22 A4 25 82 F5 
1240 82 E5 F0 35 83 F5 83 22 E6 FC 08 E6 FD 08 E6 FE 
1250 08 E6 FF 22 E0 FC A3 E0 FD A3 E0 FE A3 E0 FF 22 
1260 E2 FC 08 E2 FD 08 E2 FE 08 E2 FF 22 E4 93 FC 74 
1270 01 93 FD 74 02 93 FE 74 03 93 FF 22 8F 30 8D 31 
1280 8B 32 AF 32 EF 33 95 E0 8F 3A F5 39 F5 38 F5 37 
1290 75 3B 05 90 30 44 E0 FC A3 E0 FD A3 E0 FE A3 E0 
12A0 FF EC 44 80 FC 90 30 44 12 11 FF 90 30 44 E0 FC 
12B0 A3 A3 A3 E4 FF FE FD EC 54 80 FC E4 FB FA F9 78 
12C0 80 C3 12 11 AB 60 E4 E5 30 54 FE FF 33 95 E0 FE 
12D0 FD FC 90 30 50 12 11 FF E5 36 70 11 AF 31 EF 33 
12E0 95 E0 FE FD FC 90 30 50 12 11 FF 80 18 E5 3A 24 
12F0 FF F5 3A E5 39 34 FF F5 39 E5 38 34 FF F5 38 E5 
1300 37 34 FF F5 37 E4 F5 3C AF 32 EF 33 95 E0 FE C3 
1310 E5 3C 9F EE 64 80 F8 74 80 98 50 1E AB 33 AA 34 
1320 A9 35 85 3C 82 75 83 00 12 11 4A FF E4 FC FD FE 
1330 90 30 50 12 11 FF 05 3C 80 CE AF 3A AE 39 AD 38 
1340 AC 37 78 19 12 11 BC 8F 3A 8E 39 8D 38 8C 37 90 
1350 30 44 12 11 FF E5 3A FF E5 39 FE E5 38 FD E5 37 
1360 44 40 FC 90 30 44 12 11 FF 90 30 44 E0 FC A3 A3 
1370 A3 E4 FF FE FD EC 54 40 FC E4 FB FA F9 78 40 C3 
1380 12 11 AB 60 E4 90 30 4C A3 A3 A3 E0 54 04 FF E4 
1390 FE FD FC 7B 04 FA F9 F8 C3 12 11 AB 70 0C 90 30 
13A0 4C 12 12 0B 00 00 00 04 80 0C 90 30 4C 12 12 0B 
13B0 00 00 00 01 D3 22 15 3B E5 3B D3 94 00 40 03 02 
13C0 12 93 C3 22 8B 29 8A 2A 89 2B 8C 2C 8D 2D 90 21 
13D0 08 12 12 0B 00 00 00 20 E4 90 20 2A F0 A3 F0 F5 
13E0 2F F5 30 C3 E5 30 95 2D E5 2F 95 2C 50 55 E5 2E 
13F0 AB 29 AA 2A A9 2B 70 2A AF 01 E5 30 2F FF EF 54 
1400 03 25 E0 FF E4 33 FE E9 25 30 F9 EA 35 2F FA E9 
1410 24 03 F9 E4 3A FA C3 E9 9F F9 EA 9E FA 12 11 31 
1420 80 09 85 30 82 85 2F 83 12 11 4A FF 74 90 25 30 
1430 F5 82 E4 34 40 F5 83 EF F0 05 30 E5 30 70 A4 05 
1440 2F 80 A0 E4 F5 2F F5 30 E5 2D 24 03 FF E4 35 2C 
1450 FE EF 78 02 CE C3 13 CE 13 D8 F9 FF C3 E5 30 9F 
1460 E5 2F 9E 50 37 E5 30 AE 2F 78 02 C3 33 CE 33 CE 
1470 D8 F9 24 90 F5 82 E4 34 40 F5 83 E0 FC A3 E0 FD 
1480 A3 E0 FE A3 E0 FF 90 20 30 12 11 FF 90 20 29 74 
1490 02 F0 05 30 E5 30 70 B0 05 2F 80 AC AE 2C AF 2D 
14A0 E4 FC FD 90 21 20 12 11 FF 90 21 20 E0 F8 A3 E0 
14B0 F9 A3 E0 FA A3 E0 FB E5 2C 44 80 FE EB 45 2D FF 
14C0 EA 4E FE E9 FD E8 FC 90 21 20 12 11 FF 90 21 08 
14D0 12 12 0B 00 00 00 01 22 C2 AF C0 E0 C0 F0 C0 83 
14E0 C0 82 C0 D0 75 D0 00 C0 00 C0 01 C0 02 C0 03 C0 
14F0 04 C0 05 C0 06 C0 07 90 20 08 E0 F8 A3 E0 F9 A3 
1500 E0 FA A3 E0 55 45 FF EF 42 21 30 0C 12 90 20 08 
1510 12 12 0B 00 00 00 10 C2 0C 12 1B C0 02 15 BE 30 
1520 0A 3C C2 0A 90 20 10 E0 FC A3 E0 FD A3 E0 FE A3 
1530 E0 44 18 FF EC 90 20 10 12 11 FF 90 20 10 E0 FC 
1540 A3 E0 FD A3 E0 FE A3 E0 54 EF FF EC 90 20 10 12 
1550 11 FF 90 20 08 12 12 0B 00 00 00 04 80 60 30 0B 
1560 0E 90 20 08 12 12 0B 00 00 00 08 C2 0B 80 4F 30 
1570 0F 11 90 20 08 12 12 0B 00 00 00 80 C2 0F 90 21 
1580 50 80 23 30 09 0E 90 20 08 12 12 0B 00 00 00 02 
1590 C2 09 80 2A 30 0E 18 90 20 08 12 12 0B 00 00 00 
15A0 40 C2 0E 90 21 10 12 12 0B FF FF FF FF 80 0F 30 
15B0 08 0C 90 20 08 12 12 0B 00 00 00 01 C2 08 D0 07 
15C0 D0 06 D0 05 D0 04 D0 03 D0 02 D0 01 D0 00 D0 D0 
15D0 D0 82 D0 83 D0 F0 D0 E0 D2 AF 32 8B 29 8A 2A 89 
15E0 2B 8C 2C 8D 2D E4 90 20 2A F0 A3 F0 F5 2F F5 30 
15F0 E5 2D 24 03 FF E4 35 2C FE EF 78 02 CE C3 13 CE 
1600 13 D8 F9 FF C3 E5 30 9F E5 2F 9E 50 47 90 20 29 
1610 74 01 F0 90 20 30 E0 FC A3 E0 FD A3 E0 FE A3 E0 
1620 FF C0 04 C0 05 C0 06 C0 07 E5 30 AE 2F 78 02 C3 
1630 33 CE 33 CE D8 F9 24 90 F5 82 E4 34 40 F5 83 D0 
1640 07 D0 06 D0 05 D0 04 12 11 FF 05 30 E5 30 70 A0 
1650 05 2F 80 9C E4 F5 2F F5 30 C3 E5 30 95 2D E5 2F 
1660 95 2C 50 67 E5 2E 70 3E 74 90 25 30 F5 82 E4 34 
1670 40 F5 83 E0 FD AB 29 AA 2A A9 2B AF 01 E5 30 2F 
1680 FF EF 54 03 25 E0 FF E4 33 FE E9 25 30 F9 EA 35 
1690 2F FA E9 24 03 F9 E4 3A FA C3 E9 9F F9 EA 9E FA 
16A0 ED 12 11 77 80 1B 74 90 25 30 F5 82 E4 34 40 F5 
16B0 83 E0 AB 29 AA 2A A9 2B 85 30 82 85 2F 83 12 11 
16C0 89 05 30 E5 30 70 92 05 2F 80 8E 90 21 08 12 12 
16D0 0B 00 00 00 20 22 75 29 01 75 2A 40 75 2B 90 E4 
16E0 F5 2C F5 2D 75 2C 4E 85 29 34 85 2A 35 85 2B 36 
16F0 F5 37 7B 02 AD 2C 7F A0 12 0F BA 40 03 02 17 BD 
1700 AB 29 AA 2A A9 2B 12 11 31 64 5C 60 03 02 17 BD 
1710 90 00 01 12 11 4A F5 2D E5 2D D3 94 B2 40 03 75 
1720 2D B2 05 2C 05 2C E5 2D D3 94 00 50 03 02 17 BD 
1730 E5 2D D3 94 0F 40 04 7F 0F 80 02 AF 2D 8F 2E C3 
1740 E5 2D 95 2E F5 2D 85 29 34 85 2A 35 85 2B 36 E4 
1750 F5 37 AB 2E AD 2C 7F A0 12 0F BA 50 60 E5 2E 25 
1760 2C F5 2C E4 F5 2F E5 2E 75 F0 03 84 FF E5 2F C3 
1770 9F 50 B3 AB 29 AA 2A A9 2B 75 F0 03 E5 2F A4 F5 
1780 82 85 F0 83 12 11 4A 7F 00 FE 75 F0 03 E5 2F A4 
1790 24 01 F5 82 E4 35 F0 F5 83 12 11 4A 2F FF E4 3E 
17A0 FE 75 F0 03 E5 2F A4 24 02 F5 82 E4 35 F0 F5 83 
17B0 12 11 4A 8F 82 8E 83 F0 00 05 2F 80 A9 22 8F 29 
17C0 8D 2A 8B 2B 85 2B 2E 75 2F 40 75 30 90 E5 2E D3 
17D0 94 00 40 41 E5 2E D3 94 10 40 04 7F 10 80 02 AF 
17E0 2E 8F 2D C3 E5 2E 95 2D F5 2E 75 34 01 85 2F 35 
17F0 85 30 36 85 2C 37 AB 2D AD 2A AF 29 12 0F BA 40 
1800 01 22 E5 2D 25 2A F5 2A E5 2D 25 30 F5 30 E4 35 
1810 2F F5 2F 80 B8 90 21 08 12 12 0B 00 00 00 20 E4 
1820 90 20 2A F0 A3 F0 FB E5 2B 24 03 13 13 54 3F FF 
1830 EB C3 9F 50 28 EB 25 E0 25 E0 24 90 F5 82 E4 34 
1840 40 F5 83 E0 FC A3 E0 FD A3 E0 FE A3 E0 FF 90 20 
1850 30 12 11 FF 90 20 29 74 02 F0 0B 80 CA AF 2B E4 
1860 FC FD FE 90 21 20 12 11 FF 90 21 20 E0 F8 A3 E0 
1870 F9 A3 E0 FA A3 E0 FB EB 45 2B FF EA 44 80 FE E9 
1880 FD E8 FC 90 21 20 12 11 FF 90 21 08 12 12 0B 00 
1890 00 00 01 D3 22 12 16 D6 90 20 00 12 12 0B 00 00 
18A0 04 00 90 20 00 E0 FC A3 E0 FD A3 E0 FE A3 E0 FF 
18B0 EE 54 FB FE EC 90 20 00 12 11 FF 90 20 00 E0 FC 
18C0 A3 E0 FD A3 E0 FE A3 E0 44 01 FF EC 90 20 00 12 
18D0 11 FF 90 21 18 12 12 0B 00 00 00 40 90 21 0C 12 
18E0 12 0B FF FF FF FF 90 21 10 12 12 0B FF FF FF FF 
18F0 90 21 04 E0 FC A3 E0 FD A3 E0 FE A3 E0 44 80 FF 
1900 EC 90 21 04 12 11 FF 90 20 0C 12 12 0B 00 00 00 
1910 F4 90 20 0F E0 F5 45 75 08 FF 43 A8 81 90 20 10 
1920 E0 FC A3 E0 FD A3 E0 FE A3 E0 44 01 FF EC 90 20 
1930 10 12 11 FF 22 8F 29 8D 2A 8B 2B 75 2E 40 75 2F 
1940 90 E4 90 20 2A F0 A3 F0 F9 E5 2B 24 03 13 13 54 
1950 3F FF E9 C3 9F 50 27 90 20 29 74 01 F0 90 20 30 
1960 E0 FC A3 E0 FD A3 E0 FE A3 E0 FF 85 2F 82 85 2E 
1970 83 75 F0 04 E9 12 12 3C 12 11 FF 09 80 CB E5 2B 
1980 D3 94 00 40 42 E5 2B D3 94 10 40 04 7F 10 80 02 
1990 AF 2B 8F 2D C3 E5 2B 95 2D F5 2B 75 33 01 85 2E 
19A0 34 85 2F 35 85 2C 36 AB 2D AD 2A AF 29 12 12 7C 
19B0 50 13 E5 2D 25 2A F5 2A E5 2D 25 2F F5 2F E4 35 
19C0 2E F5 2E 80 B9 C3 22 90 21 08 12 12 0B 00 00 00 
19D0 20 D3 22 8D 29 90 21 08 12 12 0B 00 00 00 20 E4 
19E0 90 20 2A F0 A3 F0 F5 2A F5 2B E5 29 24 03 13 13 
19F0 54 3F FF C3 E5 2B 9F E5 2A 94 00 50 2A E5 2B AE 
1A00 2A 78 02 C3 33 CE 33 CE D8 F9 F5 82 8E 83 12 11 
1A10 CF 90 20 30 12 11 FF 90 20 29 74 02 F0 05 2B E5 
1A20 2B 70 C7 05 2A 80 C3 E4 90 20 2A F0 A3 F0 AF 29 
1A30 FC FD FE 90 21 20 12 11 FF 90 21 20 E0 F8 A3 E0 
1A40 F9 A3 E0 FA A3 E0 FB EB 45 29 FF EA 44 80 FE E9 
1A50 FD E8 FC 90 21 20 12 11 FF 90 21 08 12 12 0B 00 
1A60 00 00 03 22 78 7F E4 F6 D8 FD 75 81 45 02 1A AB 
1A70 02 1C 13 E4 93 A3 F8 E4 93 A3 40 03 F6 80 01 F2 
1A80 08 DF F4 80 29 E4 93 A3 F8 54 07 24 0C C8 C3 33 
1A90 C4 54 0F 44 20 C8 83 40 04 F4 56 80 01 46 F6 DF 
1AA0 E4 80 0B 01 02 04 08 10 20 40 80 90 1D 0C E4 7E 
1AB0 01 93 60 BC A3 FF 54 3F 30 E5 09 54 1F FE E4 93 
1AC0 A3 60 01 0E CF 54 C0 25 E0 60 A8 40 B8 E4 93 A3 
1AD0 FA E4 93 A3 F8 E4 93 A3 C8 C5 82 C8 CA C5 83 CA 
1AE0 F0 A3 C8 C5 82 C8 CA C5 83 CA DF E9 DE E7 80 BE 
1AF0 90 30 04 E0 44 80 F0 30 02 3D 30 03 0D 90 30 08 
1B00 74 01 F0 30 04 04 E0 54 FD F0 90 20 10 E0 FC A3 
1B10 E0 FD A3 E0 FE A3 E0 44 20 FF EC 90 20 10 12 11 
1B20 FF 90 30 07 E0 54 F7 F0 90 30 00 E0 44 08 F0 90 
1B30 30 02 E0 44 08 F0 22 90 20 10 A3 A3 A3 E0 54 DF 
1B40 FF E4 FE FD FC 90 20 10 12 11 FF 90 30 07 E0 44 
1B50 08 F0 90 30 00 E0 54 F7 F0 22 8E 30 8F 31 8C 32 
1B60 8D 33 74 FF FD FC E5 33 15 33 AE 32 70 02 15 32 
1B70 4E 60 48 7B 80 EB 60 31 EC 30 E7 0F ED 25 E0 FD 
1B80 EC 33 FC 63 05 05 63 04 80 80 07 ED 25 E0 FD EC 
1B90 33 FC 85 31 82 85 30 83 E4 93 5B 60 06 63 05 05 
1BA0 63 04 80 EB C3 13 FB 80 CC 05 31 E5 31 70 02 05 
1BB0 30 ED 90 A5 A5 F0 EC A3 F0 80 AB AE 04 AF 05 22 
1BC0 90 20 10 E0 FC A3 E0 FD A3 E0 FE A3 E0 54 FB FF 
1BD0 EC 90 20 10 12 11 FF 90 20 00 12 12 0B 00 00 04 
1BE0 00 90 20 00 12 12 0B 00 00 00 01 90 21 04 E0 FC 
1BF0 A3 E0 FD A3 E0 FE A3 E0 44 80 FF EC 90 21 04 12 
1C00 11 FF 90 20 0C 12 12 0B 00 00 00 F4 90 20 0F E0 
1C10 F5 45 22 12 1C 98 12 1C 59 12 0A 7D 12 18 95 12 
1C20 1A F0 30 0D FD 90 21 08 12 12 0B 00 00 00 20 90 
1C30 20 08 12 12 0B 00 00 00 20 C2 0D 90 20 FB E0 B4 
1C40 82 12 90 20 FA E0 B4 0C 0B 90 21 08 12 12 0B 00 
1C50 00 00 10 22 12 00 0E 80 C9 90 30 40 12 12 0B 00 
1C60 00 00 17 90 30 44 E0 FC A3 E0 FD A3 E0 FE A3 E0 
1C70 FF EC 44 80 FC 90 30 44 12 11 FF 90 30 44 E0 FC 
1C80 A3 A3 A3 E4 FF FE FD EC 54 80 FC E4 FB FA F9 78 
1C90 80 C3 12 11 AB 60 E4 22 75 89 21 75 88 A0 75 8A 
1CA0 68 75 8C C5 D2 8C 75 8D DF 75 98 52 43 87 80 D2 
1CB0 8E 75 A8 82 75 8E 02 90 20 10 E0 FC A3 E0 FD A3 
1CC0 E0 FE A3 E0 54 FE FF EC 90 20 10 02 11 FF C2 AF 
1CD0 C0 E0 C2 8C 75 8A 68 75 8C C5 D2 8C E5 41 45 40 
1CE0 60 08 E5 41 15 41 70 02 15 40 E5 43 45 42 60 08 
1CF0 E5 43 15 43 70 02 15 42 D0 E0 D2 AF 32 8E 29 8F 
1D00 2A 85 2A 2B 85 29 2C AE 2B AF 2C 22 01 3E 14 01 
1D10 44 00 01 3F 00 01 20 00 00 00 00 00 00 00 00 00 
1D20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1D30 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1D40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1D50 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1D60 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1D70 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1D80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1D90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1DA0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1DB0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1DC0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1DD0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1DE0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1DF0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1E00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1E10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1E20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1E30 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1E40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1E50 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1E60 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1E70 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1E80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1E90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1EA0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1EB0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1EC0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1ED0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1EE0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1EF0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1F00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1F10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1F20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1F30 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1F40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1F50 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1F60 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1F70 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1F80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1F90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1FA0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1FB0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1FC0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1FD0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1FE0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
1FF0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 12 08 
2000 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2010 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2020 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2030 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2040 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2050 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2060 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2070 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2080 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2090 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
20A0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
20B0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
20C0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
20D0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
20E0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
20F0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2100 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2110 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2120 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2130 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2140 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2150 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2160 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2170 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2180 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2190 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
21A0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
21B0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
21C0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
21D0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
21E0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
21F0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2200 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2210 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2220 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2230 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2240 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2250 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2260 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2270 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2280 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2290 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
22A0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
22B0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
22C0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
22D0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
22E0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
22F0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2300 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2310 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2320 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2330 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2340 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2350 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2360 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2370 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2380 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2390 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
23A0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
23B0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
23C0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
23D0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
23E0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
23F0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2400 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2410 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2420 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2430 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2440 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2450 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2460 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2470 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2480 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2490 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
24A0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
24B0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
24C0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
24D0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
24E0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
24F0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2500 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2510 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2520 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2530 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2540 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2550 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2560 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2570 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2580 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2590 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
25A0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
25B0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
25C0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
25D0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
25E0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
25F0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2600 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2610 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2620 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2630 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2640 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2650 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2660 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2670 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2680 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2690 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
26A0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
26B0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
26C0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
26D0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
26E0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
26F0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2700 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2710 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2720 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2730 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2740 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2750 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2760 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2770 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2780 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2790 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
27A0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
27B0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
27C0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
27D0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
27E0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
27F0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2800 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2810 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2820 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2830 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2840 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2850 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2860 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2870 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2880 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2890 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
28A0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
28B0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
28C0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
28D0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
28E0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
28F0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2900 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2910 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2920 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2930 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2940 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2950 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2960 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2970 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2980 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2990 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
29A0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
29B0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
29C0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
29D0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
29E0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
29F0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2A00 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2A10 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2A20 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2A30 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2A40 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2A50 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2A60 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2A70 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2A80 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2A90 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2AA0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2AB0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2AC0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2AD0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2AE0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2AF0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2B00 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2B10 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2B20 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2B30 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2B40 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2B50 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2B60 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2B70 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2B80 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2B90 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2BA0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2BB0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2BC0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2BD0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2BE0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2BF0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2C00 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2C10 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2C20 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2C30 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2C40 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2C50 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2C60 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2C70 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2C80 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2C90 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2CA0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2CB0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2CC0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2CD0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2CE0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2CF0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2D00 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2D10 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2D20 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2D30 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2D40 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2D50 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2D60 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2D70 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2D80 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2D90 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2DA0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2DB0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2DC0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2DD0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2DE0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2DF0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2E00 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2E10 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2E20 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2E30 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2E40 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2E50 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2E60 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2E70 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2E80 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2E90 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2EA0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2EB0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2EC0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2ED0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2EE0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2EF0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2F00 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2F10 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2F20 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2F30 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2F40 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2F50 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2F60 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2F70 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2F80 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2F90 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2FA0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2FB0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2FC0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2FD0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2FE0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
2FF0 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 3E 
3000 59 08 18 E8 96 00 00 06 02 00 00 55 00 00 00 00 
3010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
3020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
3030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
3040 09 09 09 09 09 09 09 09 09 09 09 09 09 09 09 09 
3050 09 09 09 09 09 09 09 09 09 09 09 09 09 09 09 09 
3060 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
....
.... 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
....
FCF0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FD00 00 00 00 1C 00 80 D0 07 02 00 00 00 09 00 00 00 
FD10 00 01 08 03 10 10 01 FF 00 00 00 00 00 00 00 00 
FD20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FD30 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FD40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FD50 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FD60 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FD70 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FD80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FD90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FDA0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FDB0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FDC0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FDD0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FDE0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FDF0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FE00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FE10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FE20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FE30 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FE40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FE50 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FE60 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FE70 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FE80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FE90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FEA0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FEB0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FEC0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FED0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FEE0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FEF0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FF00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FF10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FF20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FF30 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FF40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FF50 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FF60 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FF70 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FF80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FF90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FFA0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FFB0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FFC0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FFD0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FFE0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
FFF0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
Exiting Radio Event Consumer.
Exiting Data Consumer.

Antenna, but particularly broadband antenna

I've also written up a seperate, longer, page on the challenges and solutions when implementing broadband antenna.

When I want to do some scanning that takes advantage of the tuner's very wide ranges I use five types of antenna: discone, spiral, dual planar disks, vivaldi (tapered slot), and horns (TEM and pyramidal). Discone, dual planar disk, and archimedian spiral antenna can omnidirectionally cover almost the full range of the E4000 tuner but things get a bit too large to go all the way to the 24 Mhz of the R820T. You can refer to the seperate spiral antenna page for construction and technical details. To build my discone I followed Roklobsta's D.I.Y. Discone for RTLSDR (archive.org mirror). With just a discone and rtl_power it's possible to see lots of LEO satellite carrier frequencies doppler across the spectrum.

To get an idea of how much you can see with a discone here's a directory where I produce ~2 to 4 day long ~70 to 1000 MHz range 25KHz resolution 45k*10k pixel spectrograms. They each have a javascript zoomable interface to load small tiles progressively. An example. With just a discone and rtl_power it's possible to see lots of LEO satellite carrier frequencies doppler across the spectrum.

But with a band specific helix in a cone reflector (helicone) many more satellites can be picked up. The previous is a link to a zoomable spectrogram of ~2 days of the 1616-1626 MHz satellite band that Iridium satellites use. No LNA was used. There's plenty of RFI/EMI even through a 1 GHz high pass but the satellite doppler passes are clearly there in numbers if you zoom in far enough.

When using such broadband antenna, or even a band specific helix, it is possible to pick up powerful out of band signals due to overloading or incomplete mixer filtering. It's important to identify any extraordinarily powerful transmitters nearbye and filter them out. In my case I have a 50w transmitter at 461 MHz across the street always going full power. I bought a custom tuned 3 cavity notch filter from PAR Electronics. This limits the upper frequency range to 1GHz but does at least solve the RFI problem.

Usually the spectra are much cleaner when using directional and resonant antenna instead of wideband omnidirectionals. But many directional antenna like helix and log periodic dipoles have very large out of band sidebands on low frequencies not in the designed range.

Page Sections

• Intro
• Hardware
• My Interferometer
• Links/Datasheets (here)
• Installing RTLSDR and GNU Radio
• RTLSDR Applications Notes
• Pagers
• Gqrx on Ubuntu 10.04
• LTE Scanner on Ubuntu 10.04
• Dongle Logger
• GNU Radio Companion
• Clocks
• Broadband Antenna

RTL-SDR Links

• rtl-sdr wiki - osmocom
• Known applications - rtl-sdr wiki - osmocom
• rtlsdr.org wiki
• r/rtlsdr - reddit group
• Ultra Cheap SDR - google group
• RTL-SDR - yahoo group
• AB9IL's rtl2832 software defined radio overview

Warning: I'm learning as I go along. There are errors. Refer to the proper documentation and original sources first.

git clone git://git.osmocom.org/rtl-sdr.git
cd rtl-sdr; mkdir build; cd build; cmake ../ ; make; sudo make install; sudo ldconfig

This is all really out of date. Even GNU Radio 3.7 is old now. build-gnuradio is no longer maintained, mostly because most distros have recently up to date GNU Radio packages these days, even on OSX too. So if you're doing this in 2023 or later try your system repo GNU Radio first. Or whatever comes as a dependency when you install gqrx from your repos. Radioconda is another modern option.

OLD STUFF BELOW YOU SHOULD PROBABLY IGNORE

You don't need GNU Radio to use the rtlsdr dongles in sdr mode, but there are many useful apps that depend on it. patchvonbraun has made setting up and compiling GNU Radio and RTLSDR with all the right options very simple on Ubuntu and Fedora. It automates grabbing the latest of everything from git and compiling. It will also uninstall any packages providing GNU Radio already installed first. Simply run, http://www.sbrac.org/files/build-gnuradio, and it'll automate downloading and compiling of prequisites, libraries, correct git branches, udev settings, and more. I had no problems using Ubuntu 10.04, 12.04, or 14.04. These days (2015) pybombs is slowly taking over for build-gnuradio but for now this works best.

If you're thinking about trying this in a virtual machine: don't. If you do get it partially working it'll still suck.

As an aside: If you're an OSX user then you can use the MacPorts version of GNU Radio (including gqrx, etc) maintained by Michael Dickens.

mkdir gnuradio
cd gnuradio
wget http://www.sbrac.org/files/build-gnuradio
chmod a+x build-gnuradio
./build-gnuradio --verbose          # default is latest 3.7
*or*
./build-gnuradio -o --verbose       # install old 3.6.5.1

Install 3.7. Most gnu radio projects have been ported to it as default. Only a few old things will require 3.6.

An (re)install looks like this. It might be useful to save the log output for future reference. Then test it. The test output below is from a very old version of rtl_test with an E4K dongle. Newer versions, and R820T tuners will output slightly different text.

rtl_test -t
Found 1 device(s):
  0:  ezcap USB 2.0 DVB-T/DAB/FM dongle

Using device 0: ezcap USB 2.0 DVB-T/DAB/FM dongle
Found Elonics E4000 tuner
Benchmarking E4000 PLL...
[E4K] PLL not locked!
[E4K] PLL not locked!
[E4K] PLL not locked!
[E4K] PLL not locked!
E4K range: 52 to 2210 MHz
E4K L-band gap: 1106 to 1247 MHz

Once GNU Radio is installed the "Known Apps" list at the rtl-sdr wiki is a good place to start. Try running a third party receiver, a python file or start up GNU Radio Companion (gnuradio-companion) and load the GRC flowcharts. If you're having "Failed to open rtlsdr device #0" errors make sure something like /etc/udev/rules.d/15-rtl-sdr.rules exists and you've rebooted.

Updating

When updating you can just repeat the install instructions which is simple but long. The advantage to repeating the full process is mainly if there are major changes in the gr-osmosdr as well as rtl-sdr. It'll do things like ldconfig for you.

./build-gnuradio -e gnuradio_build

• keenerd's rtl-sdr branch
  • This experimental branch contains a number of useful low processing power utilities, expansions of the original rtl tools, and improvements to the R820T driver re-tuning speed. A lot of them have already been merged into the librtlsdr master but rtl_fm and rtl_power fixes, features and bugs appear here first. rtl_fm is for scanning, listening, and decoding (and not just FM), rtl_adbs for plane watching with an external ads-b viewer, rtl_eeprom for checking and *setting* serial numbers and related data if your dongle has an eeprom. And as of 2013-09-20, rtl_power, a total power frequency scanner. These tools are very good for slow machines or when you want to do command line automation. Just build it like the osmocom rtlsdr page does for the vanilla install. Use these on the raspberry pi.

  git clone https://github.com/keenerd/rtl-sdr.git
  git clone https://github.com/keenerd/rtl-sdr-misc

  cd rtl-sdr; mkdir build; cd build; cmake ../ -DINSTALL_UDEV_RULES=ON; make; sudo make install-udev-rules; sudo ldconfig

  Most people use rtl_power for smaller total bandwidths (<200 MHz) and higher spectral resolution using the default FFT mode. This is visualized with keenerd's heatmap.py and can result in some really impressive plots when done with ~25% crop mode. Just refer to the -h "help" in rtl_power for instruction. There is also an rtl_power guide at keenerd's website.

  For RMS average power mode, which kicks in automatically for FFT bin sizes 1 MHz and larger, I do visualization of the resulting .csv file with gnuplot. Because the entire bandwidth is summed and saved as one value the the data rate to disk, and spectrogram dimensions are much lower than FFT mode.

  Example gnuplot visualization, annotated, and the gnuplot format, and colour palettes used to generate them.

  If you do a large number of frequency hops, (hundreds) then the time adds up. On my two computers the R820T tuner dongles average about 55 milliseconds per retune and sample cycle. I sometimes have dongles that'll fail to lock pll and go into a loop. The -e parameter sets a time limit for a run. Combining this time limit with a bash while loop results in pretty low downtime with resiliance to rtlsdr and USB failures.

  # 0.055 seconds *((1724-24) MHz/(1 MHz)) = 93.5 seconds = "-i".
  while true; do ./rtl_power -f 24M:1724M:1M -i 94 -g 20.7 -p 30 -e 1h >> 2013-12-02_totalpower_r820t_24-1724_1M_94s.csv; done

  To combine the results from multiple dongles just cat the files together. But on gnuplots end each new .csv filename requires you to manually edit the gnuplot format. Additionally you need to set the output spectrogram filename and a pixel width. I find for 1000 Mhz @ 1 MHz that approximately 1000px per 100 MB of file size is required to cover all gaps.

  gnuplot gnuplot-format-rms-mode.txt

  And that pops out a png.

  For rtl_fm stuff refer to keenerd's site's Rtl_fm Guide.

• Spektrum: an rtl_power GUI frontend:
  • There are a lot of rtl_power GUI frontends but the most useful for me is Spektrum. It uses a modified rtl_power with a Processing GUI front-end. It's available for linux and windows. One of it's best features is the "relative mode" for use in measuring changes in antennas and filters.


• patchvonbraun (Marcus Leech)'s multimode:
  • AM, FM, USB, LSB , WFM. TV-FM, PAL-FM. Very nice, easy to use (screenshots: main, scanning). It has an automated scanning and spectral zoom features with callbacks to click on the spectrogram or panorama to tune to the frequency of interest. There's a toggle for active gain control too. The way to get it is,

    svn co https://www.cgran.org/svn/projects/multimode

    then instead of using GRC, just run the multimode.py as is.

    make install
    python multimode.py

    If you run it outside of the svn created directory you might need to append ~/bin to pythonpath to find the helper script. If you used build-gnuradio it'll tell you what this is at the end of the install.

    Alternately set it in your ~/.bashrc. If you do the below make sure to reload in the terminal by "source ~/.bashrc")

    PYTHONPATH=/usr/local/lib/python2.6/dist-packages:~/bin
    export PYTHONPATH;

    When setting the sample rate it is rounded-down to a multiple of 200 Ksps so the decimation math works out.

    python multimode.py --srate=2.4M # use normal mode with 2.4 MHz bandwidth
    ./multimode.py --devinfo="rtl=0,direct_samp=1" # use direct sample mode
    python multimode.py --help

    If you have overruns like "OOOOoo..." then try reducing the sample rate or pausing the waterfall or spectrum displays.

    "The audio subsystem uses 'a' as the identifier, and UHD uses 'u'. With RTLSDR, it'll issue 'O' when it experiences an overrun. Which means that your machine isn't keeping up with the data stream. Sometimes buffering helps, but only if your machine is right on the edge of working properly. If it really can't, on average "keep up", no amount of buffering will help."

    If you have overruns like "aUaUaUaUa" or just "aaa" then the audio system is asking for samples at a higher rate than the DSP flow can provide (44vs48Khz, etc). Use "aplay -l" to get a list of the devices on your system.

    aplay -l
    

    The hw:X,Y comes from this mapping of your hardware -- in this case, X is the card number, while Y is the device number. Or you can use "pulse" for pulseaudio. Try specifying,

    python multimode.py--ahw hw:0,0

• gqrx:
  • Written by Alexandru Csete OZ9AEC "gqrx is an experimental AM, FM and SSB software defined receiver". The original version did not have librtlsdr support so changes were made by a number of others to add it. A couple weeks later Csete added gr-osmosdr support to the original. Dekar established a non-pulseaudio port of gqrx for Mac OSX. GNU Radio 3.7 has recently been released and it is not exactly backwards compatible. patchvonbraun's build-gnuradio.sh pulls 3.6.5 3.7.x by default.

    As of August 9th 2013 Gqrx 2.2.0 has been released. This upgraded version can now be installed as binaries with all of it's dependencies pre-packaged on both Ubuntu linux (a custom PPA, no 10.04 packages) and Mac OS X! That includes all the GNU Radio stuff. So this is an all-in-one alternative to building GNU Radio from source.

    I think this person's guide is better than mine.

    git clone https://github.com/csete/gqrx.git
    cd gqrx
    # on Ubuntu/Debian, sudo apt-get install qtcreator , if you don't have it.
    qtcreator gqrx.pro 	# press the build button (the hammer)
    # or avoid qtcreator and do it manually. if you have qt5 too, use "qmake-qt4"
    qmake
    make
    

  • rtlsdr w/Gqrx on N900 phones
    • xes provides pre-compiled packages of Gqrx and the GNU Radio dependencies for N900 linux cell phones.


• SDR#:
  • Written by prog (Youssef) for Windows. It is probably the best general purpose software for rtlsdr devices. Mono is slow and ugly on linux but if you restrict the sample rate it works fine. It's probably the easiest program to use, has the most diverse plugin ecosystem (example: Vasili_ru's plugins), and has the best DSP and features for dealing with the quirks of the rtlsdr dongles.
    

    As of 2015-09-14 the changes to Mono 4 allow SDR# to be viable to run on linux again. Make sure you have the latest Mono 4 though. This still requires soft linking in your system rtlsdr and portaudio library to the sdrshape.exe dir like below,

    ln -s  /usr/local/lib/librtlsdr.so librtlsdr.dll
    ln -s /usr/lib/x86_64-linux-gnu/libportaudio.so.2 libportaudio.so

    Just make sure you link your actual system rtlsdr and libportaudio, not my example path above. On debian/ubuntu find it by using locate,

    locate portaudio.so

    Roklobsta's rtlsdr.org has a more detailed SDR# linux configuration guide if you're having trouble.

  • Update: As of 2015-10-15 ADBS# is no more. ADBS# is another easy to use application by prog, but specifically for plotting aviation transponders like gr-air-modes does. The distributed binaries also runs under linux with mono (or native in windows) and output virtualradar compatible data on 127.0.0.1:47806. If your antenna condition is crappy, try using filter = 1.
  
  
• gr-fosphor:
  • gr-fosphor is an amazingly fast and information dense spectrogram and waterfall visualization using OpenCL hardware acceleration. It surpasses the Wx widget elements in performance, and so usability, by far. With this visualization you can easily skip through 1 GHz of spectrum very quickly and actually notice transient signals as they pass. Right now it is not very configurable, just arrow keys for scale. But expect this to be the preferred visualization block in the future. I have written up an barebones guide to installing gr-fosphor on Ubuntu 12.04. Modern gr-fosphor requires OpenCl 2. If you only have OpenCl 1.2 installed use this commit.


• gr-air-modes:
  • A decoder of aviation transponder Mode S including ads-b reports near 1090 Mhz. It can be coupled to software to show plane positions in near real time (ex: VirtualRadar). This works under mono on Ubuntu 12.04 but not 10.04. Originally written by Nick Foster (bistromath) and adapted to rtlsdr devices first by Steve Markgraf (stevem), bistromath later added rtlsdr support. Here's an example of basic decoding done with the stock antenna on the early version by stevem. Nowdays it's better to use bistromaths'.

    As of July 23, 2013 there was a major update to gr-air-modes which now includes a nice google maps overlay and works on gnu radio 3.7 branch only.

    git clone https://github.com/bistromath/gr-air-modes.git

    Here's an example of install process and first run looks like.

    # -d stands for rtlsdr dongle, location is "North,East"
    uhd_modes.py -d --location "45,-90"

    To use with virtual radar output add the below -P switch. Then open up virtualradar with mono and go to tools->options->basestation and put in the IP of the computer running uhd_modes. There are not many compatible planes in the USA so far so even if you are seeing lots of Mode-S broadcast in uhd_modes you might not see anything in virtualradar. Sometimes my server is running at superkuh.com:81/VirtualRadar/GoogleMap.htm.

    uhd_modes.py -d --location "45,-90" -P
    mono VirtualRadar.exe

• Dump1090:

  • Dump 1090 is a Mode S decoder specifically designed for RTLSDR devices.

    Antirezs' ADS-B program is really slick. It does not depend on GNU Radio, has a number of interactive modes, and it even optionally runs it's own HTTP server with googlemaps overlay of discovered planes; no virtualradar needed. It uses very little CPU and has impressive error correction. This is your best choice to play with plane tracking quickly.

    # run cli interactively and create a googlemaps server on localhost port 8080
    ./dump1090 --aggressive --interactive --net-http-port 8080
    # submit plane data to a tracking server
    ./dump1090 --aggressive --raw | socat -u - TCP4:sdrsharp.com:47806

• linrad:
  • A guide on how to use linrad with rtl-sdr, and a modification to the the librtlsdr e4000 tuner code to disable digital active gain! reddit thread

    "I tried various bits blindly and found a setting that eliminates the AGC in the RTL2832 chip. That is a significant part of the performance improvement."

    As of 2012-07-07 this feature was added to the main (librtlsdr) driver as well.

• LTE Cell Scanner and LTE Tracker:

  • "This is an LTE cell searcher that scans a set of downlink frequencies and reports any LTE cells that were identified. A cell is considered identified if the MIB can be decoded and passes the CRC check."

    "LTE-Tracker is a program that continuously searchers for LTE cells on a particular frequency and then tracks, in realtime, all found cells. With the addition of a GPS receiver, this program can be used to obtain basic cellular coverage maps."

    The author had only tested it on Ubuntu 12.04 but with some frustrating work replacing cmake files and compiling dependencies I made it work on 10.04. Scanner is very useful to get your dongle's frequency offset reliably and Tracker is very pretty. Remember to let your rtlsdr dongle warm up to equilibrium temperature before checking frequency error.

• kalibrate-rtl:

  • "Kalibrate, or kal, can scan for GSM base stations in a given frequency band and can use those GSM base stations to calculate the local oscillator frequency offset."

    The code was written by Joshua Lackey and made rtlsdr accessible by stevem. There is also a windows build made by Hoernchen. Let your rtlsdr dongle warm up to equilibrium temperature before running the test. When you're using this to find your frequency error it's important to use the -e option to specify intial error. 270k of bandwidth is used for GSM reception and if the error of the dongle is too large the FCCH-peak is outside the range. I compiled some install process and example usage notes.

• Simple FM (Stereo) Receiver
  • simple_fm_rcv also by patchvonbraun is the best sounding and tuning commercial FM software in my opinion. He released a major update to his gnuradio creation at the end of October.

    svn co https://www.cgran.org/svn/projects/simple_fm_rcv
    cd simple_fm_rcv/
    cd trunk
    less README
    make
    make install
    ## it'll install to ~/bin/, so I use ~/superkuh/bin below
    set PYTHONPATH=/usr/local/lib/python2.6/dist-packages:/home/superkuh/bin
    # run the python script
    python simple_fm_rcv.py
    # or edit it
    gnuradio-companion simple_fm_rcv.grc

• my DongleLogger:

  • I wrote these scripts do automatic generation of 1D spectrograms, per frequency time series plots of total power, and 2D spectral maps over arbitrary frequency ranges using multiple dongles at once. There is almost no DSP done and it is very simple but the wideband spectrograms and time series can be informative and fun regardless. It uses gnuplot for graphics generation. Obsolete. Use rtl_power instead.

    You can see a typical gallery output at, http://erewhon.superkuh.com/gnuradio/live/ but more useful are the gnuplot spectrograms it can make.

• simple_ra: simple radio astronomy

  • A simple, GRC-based tool for small-scale radio astronomy, providing both Total Power and Spectral modes. It has a graphical stripchart display, and a standard FFT display. It also records both total-power and spectral data using an external C program that records the data along with timestamps based on the Local Mean Sidereal Time.

    This is another incredible tool by patchvonbraun. It does all the heavy lifting of integration over time and signal processing to get an accurate measurement of absolute power over a range. With it he has managed to pick out the transit of the milky way at the neutral hydrogen frequency using rtlsdr sticks and a pair of yagi antenna. The log file format is text and fairly easy to parse with gnuplot but it comes with 'process_simple_tpdat' for cutting it into the bits you want and making total power or spectral component graphs. It'll make a directory called "simple_ra_data" in your home by default. Don't forget to set the --devid to rtl otherwise gnuradio won't find the gr-osmosdr source and it'll substitute a gaussian noise source.

    git clone https://github.com/patchvonbraun/gr-ra_blocks
    cd gr-ra_blocks/
    cmake . ; make ; sudo make install ; sudo ldconfig
    cd ..
    git clone https://github.com/patchvonbraun/simple_ra
    cd simple_ra;
    make
    make install
    
    # Using a single E4k tuner
    ./simple_ra --devid rtl=0,offset_tune=1 --longitude -45
    # Using a second dongle that just happens to have a R820T tuner
    ./simple_ra --devid rtl=1 --longitude -45
    # Use direct sample mode @ 1.25 MHz, log once per second, set longitude
    ./simple_ra --devid rtl=0,direct_samp=1 --freq 1.25e6 --longitude -90 --lrate 1
    # generate multi-day averaged gnuplots using sidereal time
    process_simple_tpdat 02:00:00 2.0 -t "11 GHz Test" -f 11ghz.png ~/simple_ra_data/tp-20130329-*.dat ~/simple_ra_data/tp-20130328-*.dat ~/simple_ra_data/tp-20130327-*.dat
    ./simple_ra -h (README)
    

• RTLSDR-Scanner

  • Ear to Ear Oak made this wideband total power scanner that generates 1D spectrum plots over any tunable ranges with arbitrary integration times. It can update a matplotlib python plot GUI in real time and has the ability to output cvs values as well as an internal format. It's very useful for finding what's broadcasting in your area quickly. Using it's csv output and gnuplot I visualized a scan from 54-1100 MHz.

    If you want to use the data in gnuplot you have to sort it and make sure the header is commented out.

    sort -n 54-1100_500ms.csv > sorted_54-1100_500ms.csv

    Here are some example gnuplot formats for the data.

    You can comment out the header manually but I instead prefixed a hash to the log writing behavior at line 786,

    handle.write("# Frequency (MHz),Level (dB)\n")

Pager stuff

• Thomas Sailer's multimon, "Linux Radio Transmission Decoder" which I use to (try to) decode pager transmissions around 930Mhz. And more recently Dekar's multimonNG, a fork with improved error correction, more supported modes, and *nix/osx/windows support. Dekar also supplied a GRC receiver for pagers to decode pager transmissions in real-time using fifos. zarya has made rtl_flex.py, a gnuradio based flex decoder for pagers. It can be used to decode dutch p2000 messages, for example. This fills a gap in multimon-ng pager support.

Purpose:

Obsolete. Use rtl_power instead. Automatic generation of and html gallery creation of wideband spectrograms using multiple rtlsdr dongles to divide up the spectrum. It also produces narrow band total charts, and other visualizations.

(not live): http://erewhon.superkuh.com/gnuradio/live/ - click the spectrograms for time series plot

These scripts cause the rtlsdr dongle to jump from frequency to frequency as fast as they can and take very rough total power measurement. This data is stored in human readable logs and later turned into wideband spectrograms by calling gnuplot. In order to further increase coverage of any given spectrum range multiple instances of the script can be run at once in the same directory adding to the same logs. Their combined output will be represented in the spectrogram.

Details:

I don't know much python but the python wrapper for librtlsdr pyrtlsdr was a bit easier to work with than gnu radio when I wanted to do simple things without a need for precision or accuracy. Actualy receivers with processing could be made with it too, but not by me. This is the gist of what it does,

power = 10 * math.log10(scan[freq]) = scan = self.scan(sdr, freq) = capture = sdr.read_samples(self.samples) = iq = self.packed_bytes_to_iq(raw_data) = raw_data = self.read_bytes(num_bytes)

The pyrtlsdr library can be downloaded by,

git clone https://github.com/roger-/pyrtlsdr.git

I have used the "test.py" matplotlib graphical spectrogram generator that came with pyrtlsdr as a seed from which to conglomerate my own program for spectrum observation and logging. Since I am not very good with python I had to pull a lot of the logic out into a perl script. So everything is modular. As of now the python script generates the spectrogram pngs and records signal strength (and metadata) in frequency named logs. It is passed lots of arguments.

These arguments can be made however you want, but I wrote a perl script to automate it along with a few other useful things. It can generate a simple html gallery of the most recent full spectral map and spectrograms with each linked to the log of past signal levels. Or it can additionally generate gnuplot time series pngs (example) and link those intead of the raw logs. It also calls LTE Cell Scanner and parses out the frequency offset for passing to graphfreq.py for correction. I no longer have it running because of the processor usage spikes which interrupt daily tasks. In the past I'd have rsync updating the public mirror with a big pipe every ~40 minutes.

Modifying pyrltsdr

As it is pyrtlsdr does not have the get/set functions for frequency correction even if I sent the PPM correct from the perl script. Since the hooks (?) were already in librtlsdr.py (line 60-66) but just not pythonized in rtlsdr.py they were easy to add to the library. These changes are required to use frequency correction and make the int variable "err_ppm" available. I have probably shown that I don't know anything about python with this description.

I forked roger-'s pyrtlsdr on github and added them there for review or use, https://github.com/superkuh/pyrtlsdr/commit/ffba3611cf0071dee7e1efec5c1a582e1e344c61. I apologize for cluttering up the pyrtlsdr namespace with such trivial changes but I'm new to this and github doesn't allow for private repositories.

What you should be using instead.

• rtl_power was recently (2013-08-20) released by keenerd. It does most of what my scripts do, except much better, faster, and easier. I highly recommend you try it first.
• RTLSDR Scanner by Ear To Ear Oak is awesome for generating 1D wideband spectrograms.
• Enoch Zembecowicz made a polished and useful sdr logging tool
• Panteltje's rtl_sdr_scan is another tool like RTLSDR Scanner for 1D total power scans. It is a good reference for using librtlsdr with C.
• If you are serious about measuring total power over one 2.5 Mhz range then simple_ra, or simple radio astronomy, is best.

Download

fast version: see below

• donglelogger-faster.tar.gz - all needed files including pyrtlsdr
• • radioscan_faster.pl - pyrltsdr using script; frequency setting and incrimenting, sampling, and logging.
  • graphfreqs_faster5.py - option passing, log parsing, plot making, frequency corrections wrapper, html image gallery generation
  • graphfreqs_gnuplot.py - legacy functions

slow version:

• graphfreqs.py - pyrltsdr using script; sampling, and logging
• radioscan.pl - manages graphfreqs, parses logs, makes plots, gets frequency corrections, generates gallery

Speed ups, Inline C usb reset, and avoiding dongle reinitialization... (less options)

cli switches/options

-dev 1			:: rtlsdr device ID (use to pick dongle)
-g 30			:: gain
-s 			:: interval between center frequencies
-r 2400000		:: sample rate
-d2 /path/here		:: path to the directory to put logs, plots, gallery
-c 751			:: LTC Cell scanner frequency offset correction, takes freq in Mhz of base cell
-w			:: turn on web gallery generation
-p			:: turn on gnuplot time series charts for every freq (don't use to maximize speed)
-m			:: generate full range spectrogram using all.log (this is the most useful thing)
-mr "52-1108,1248-1400,1900-2200"	:: set of frequency ranges to plot as a another spectrogram

These two scripts do fast scans within python from x to y frequency. Enabled it with -fast and make sure to set start and stop frequency with -f1 and -f2. Do not use -flist with this option.

$ while true; do perl radioscan_faster.pl -d2 /tmp/faster -f1 25 -f2 1700 -fast -g 30 -r 2400000 -s 1.2 -m -p; sleep 1; done;
Running graphfreq in non-batch fast mode 25 to 1700 Mhz at 1.2 Mhz spacings.
 Spectrograms and text output disabled.
Using LTE Cell Scanner to find frequency offset from 751 Mhz station...Found Rafael Micro R820T tuner
-44k frequency offset. Correcting -58 PPM.
Generating spectral map.

python ./graphfreqs_faster.py 40000000 2400000 30 -58 /tmp/faster 1700000000
Found Rafael Micro R820T tuner
... (repeat many, many times)

This is an example output "spectral map" (a spectrogram with a silly name).

This example output above shows the overloading effects of using a wideband discone that picks up off-band noise. Each column is made up of small squares colored by intensity of the signal. Since the scripts start at the low frequency and sweep to high there is a small time delay between the bottom and top (see it more clearly zoomed in). And this is represented as the slant of the row. Sometimes strong signals will swamp out others resulting in discontinuities displaying as small dark vertical bands.

Or fast (-fast) scan a smaller range with smaller range (-f1,-f2: 24-80Mhz), with smaller samplerate (-r: 250 Khz) at smaller intervals (-s: 400Khz steps) with a gain of ~30. Only output a large spectrogram of all frequencies to the directory specified with -d2 as spectral-map.png. This example does not use frequency offset correct (-c) for even faster speeds.

while true; do perl radioscan_faster.pl -d2 /home/superkuh/radio/2012-02-02_R820T_Discone_lowfreq -f1 24 -f2 80 -fast -g 30 -r 250000 -s 0.4 -m -p; sleep 1; done;
Running graphfreq in non-batch fast mode 24 to 80 Mhz at 0.4 Mhz spacings.
 Spectrograms and text output disabled.
Generating spectral map.

python ./graphfreqs_faster5.py 24000000 250000 30 0 /home/superkuh/radio/2012-02-02_R820T_Discone_lowfreq 80000000 400000
Found Rafael Micro R820T tuner
Exact sample rate is: 250000.000414 Hz

Combining multiple rtlsdr devices for greater speed

Full

Zoom

By splitting up the spectrum into multiple smaller slices and giving them to multiple dongles the time required for one scan pass can be greatly improved. The above spectrogram is made with 2 dongles, one for the lower half and one for the upper. It is from ryannathans who also contributed the code for for specifying device ID. This is as simple as running the script twice but giving each instance a different "-dev" argument to specify device ID. You can run as many rtlsdr devices with my scripts as you wish (up to the USB and CPU limits). If they are using the same directory (-d2) their log data will be combined automagically for better coverage.

while true; do perl radioscan_faster.pl -d2 /home/superkuh/radio/2013-06-09_multidongle -f1 25 -f2 525 -fast -g 40 -r 2400000 -s 1.2 -m -dev 0; sleep 1; done;
...
Found Rafael Micro R820T tuner

while true; do perl radioscan_faster.pl -d2 /home/superkuh/radio/2013-06-09_multidongle -f1 525 -f2 1025 1100 -fast -g 29 -r 2400000 -s 1.2 -m -dev 1; sleep 1; done;
...
Found Elonics E4000 tuner

Outlier signals skewing your color map scale?

Sometimes I get corrupt samples that show a signal level of +60dB. These skew the scale of the output spectrograms. If I notice that they have occurred during a long run I'll use grep to find them and remove them manually. I replace the signal level with the level of the previous non-corrupt sample. In the future I'll build this kind of outlier removal in to the scripts, or sanity check before writing them.

grep -rinP " (3|4|5|6)\d+\.\d+" *.log

All the incremental improvements in speed I've made above are okay but not very easy to maintain with multiple script types (bash/perl/python). I'm slowly putting together an Inline C based perl wrapper for exposing librtlsdr's functions within a perl script to write this as a standalone in perl. This is slow work because I've never done anything like it before.

rtlsdrperl - what if there were a perl wrapper for librtlsdr?

Well, there never will be. But here's some example code anyway.

#!/usr/bin/perl
use Inline C => DATA => LIBS => '-L/usr/local/lib/ -lrtlsdr -lusb';
use warnings;
use strict;

my $fuckingtest = get_device_name(0);
print "Device name: $fuckingtest\n";
my $fuckingtest2 = get_device_count();
print "# Devices: $fuckingtest2\n";

__END__
__C__
const char* rtlsdr_get_device_name(uint32_t index);
char * get_device_name(int count) {
	char* res = rtlsdr_get_device_name(count);
	return res;
}

uint32_t rtlsdr_get_device_count(void);
int get_device_count() {
	int hem = rtlsdr_get_device_count();
	return hem;
}

Older version

graphfreqs.py

You have to have the modified pyrtlsdr with the get/set functions for frequency correction. LTE Cell Scanner should also be installed so the "CellSearch" binary is available. Then download the two scripts above and put them in the same directory. For large bandwidths sampled this feature, ppm error correction, has an unnoticably small effect but I wanted to add it anyway.

To call the spectrogram/log generator by itself for 431.2 Mhz at 2.4MS/s with a gain of 30 and frequency correction of 58 PPM use it like,

python graphfreqs.py 431200000 2400000 30 58

I've disabled the matplotlib (python) per frequency spectrogram plots for frequencies over 1 Ghz because there's not much going on up there. Also, the x-axis ticks and labels become inaccurate for some reason.

Logs and format

The signal strength logs, named by frequency (e.g. 53200000.log), use unix time and are comma seperated with newlines after each entry. In order of columns it is: unix time , relative signal level , gain in dB, PPM correction.

1345667680.28 , -34.65 , 29 , 57
1345667955.59 , -34.67 , 29 , 57
1345668004.37 , -34.55 , 29 , 57
1345668110.06 , -33.88 , 29 , 57

It also generates a log file with all frequencies for use with gnuplot, all.log. This file has unixtime first, then frequency, then gain and ppm error.

1347532002.5 52000000 -14.84 29.0 58
1347532004.88 53200000 -17.84 29.0 58
1347532007.04 54400000 -17.98 29.0 58
1347532009.04 55600000 -19.78 29.0 58
1347532011.02 56800000 -24.04 29.0 58
1347532012.98 58000000 -26.21 29.0 58
1347532014.92 59200000 -25.10 29.0 58

radioscan.pl

The radioscan.pl script is used to automate calling graphfreqs in arbitrary steps. To generate plots and signal strength for 52 Mhz to 1108 Mhz with a gain of 30, sample rate of 2.4MS/s, and an interval between center frequencies of 1.2 Mhz, call it like,

$ perl radioscan.pl -flist "52-1108,1248-2200" -g 30 -r 2400000 -s 1.2

cli switches/options

-flist "52-1108,1248-2200"  :: sets of frequency ranges to scan.
-g 30			:: gain
-s 			:: interval between center frequencies
-r 2400000		:: sample rate
-d1 /path/here 		:: path to where the scripts are if now pwd
-d2 /path/here		:: path to the directory to put logs, plots, gallery
-c 751			:: LTC Cell scanner frequency offset correction, takes freq in Mhz of base cell
-w			:: turn on web gallery generation
-p			:: turn on gnuplot time series charts for every freq
-m			:: generate full range spectral map using all.log
-mr "52-1108,1248-1400,1900-2200"	:: set of frequency ranges to plot as a another spectral map

Because I can use the default directories I keep it running like the below, but anyone else should make sure to set -d2.

$ while true; do perl radioscan.pl -flist "52-1108,1248-2200" -g 30 -r 2400000 -s 1.2 -w -c 751 -p -m -mr "52-1108"; sleep 1; done;

Running pyrtl graphfreq batch job 52 to 1108 Mhz at 1.2 Mhz spacings.
Using LTE Cell Scanner to find frequency offset from 751 Mhz station...Found Elonics E4000 tuner
42.6k frequency offset. Correcting 56 PPM.
Generating spectral map.
Generating another spectral map over only 52-1108.

python ./graphfreqs_offset.py 52000000 2400000 30 56
Found Elonics E4000 tuner
python ./graphfreqs_offset.py 53200000 2400000 30 56
Found Elonics E4000 tuner
python ./graphfreqs_offset.py 54400000 2400000 30 56
Found Elonics E4000 tuner
...
python ./graphfreqs_gnuplot.py 316000000 2400000 30 56
Found Elonics E4000 tuner
Dongle froze, reseting it's USB device...
Resetting USB device /dev/bus/usb/001/017
Reset successful
python ./graphfreqs_gnuplot.py 317200000 2400000 30 56
Found Elonics E4000 tuner
..
Generating page, moving images.

starting rsync...

Tuner/USB freeze solution with unplugging

edit: as of Jan 5th 2013, librtlsdr has added soft reset functionality

Since graphfreqs.py's initializing and calling of rtl-sdr happens so frequently there are sometimes freezes. To fix these the USB device has to be reset. In the past I would accomplish this by un and re-plugging the cord manually. But that meant lots of downtime when I was away or sleeping. So, I've added in a small C program to the perl script using Inline::C that exposes a function, resetusb(). It is used if the eval loop around the graphfreqs call takes more than 10 seconds. This means you need Inline::C to run this script. To look at the original C version with a good explanation of how to use it click here.

sub donglefrozen {
	my $usbreset;
	my @devices = split("\n",`lsusb`);
	foreach my $line (@devices) {
		if ($line =~ /\w+\s(\d+)\s\w+\s(\d+):.+Realtek Semiconductor Corp\./) {
			$usbreset = "/dev/bus/usb/$1/$2";
			resetusb($usbreset);
}}}

__END__
__C__
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <linux/usbdevice_fs.h>

int resetusb(char *dongleaddress)
{
	const char *filename;
	int fd;
	int rc;
	filename = dongleaddress;
	fd = open(filename, O_WRONLY);
	if (fd < 0) {
		perror("Error opening output file");
		return 1;
	}
	printf("Resetting USB device %s\n", filename);
	rc = ioctl(fd, USBDEVFS_RESET, 0);
	if (rc < 0) {
		perror("Error in ioctl");
		return 1;
	}
	printf("Reset successful\n");
	close(fd);
	return 0;
}

My rtlsdr receiver + w/gnuradio implementation of the 11 GHz VSRT solar interferometer

As far as I understand it, the VSRT design is a subset of intensity interferometer that uses the frequency error between multiple 11 GHz satellite TV "low noise downconverter block" (LNBF) clocks to create a beat frequency in the total power integrated. I am basically copying the MIT Haystack Very Small Radio Telescope (VSRT) but replacing the discrete component integrator and USB video input device with an rtlsdr dongle. The idea is to spend as little on hardware as possible.

With modern LNBF the error between same model parts is about 30 ppm which results in beat frequencies of ~100 KHz at the 10 GHz of the mixers. With this kind of front-end there are no nulls but the fringe modulation can still be read out as variations in count of histogram bins that contain the beat frequency (in the total power fft). This intensity measurement proxy traces out the the envelope of the fringes and varies as a sinc function of distance between antenna. Knowing this and the distance can give you high angular diameter and position measurements of very bright radio sources.

$75 2x 18" satellite dishes w/mounts shipped
$10 2x Ku LNFB (PLL321 S-2, ~30ppm error, RDA3560 w/27Mhz xtal.)
$10 rtlsdr receiver (r820t or e4k, ~30ppm error)
$10 power combiner (cheaper ones work too)
$5 coaxial power injector (LPI 2200)
$20 coaxial power supply (LPI 188PS) + diodes
$20 100ft RG6 quadshield + F connectors
$130 Two Dish Position Motors (HH90)
$60 DVB-S PCI card (Skystar 2, DiSEqC 1.2)
$10 DiSEqC 1.2 switch
$80 PVC, metal stock, drill bits

Historical and other context.

For a detailed mathematical explanation of VSRT see MIT Haystack's VSRT Introduction. There is also a thread on the Society for Amateur Radio Astronomers list discussing the VSRT design. The more general concept of intensity interferometry, where you correlate total power instead of frequency, was originally developed by Hanbury-Brown & Twiss. Roger Jennison was around too. "The Early Years of Radio Astronomy: Reflections Fifty Years after Janskys Discovery" by W T Sullivan (2005) is an excellent source about Hanbury Brown and Twiss's side of it. The chapter "The Invention and Early Devlopment of The Intensity Interferometer" (pdf) is fascinating. Also see "The Development of Michelson and Intensity Long Baseline Interferometry" (pdf). It covers not only the technical concepts but also historical context, detailed hands-on implementations, and other personal anectdotes. And check out Jennison's book "Radio Astronomy" (1966)) as he invented the process of phase closure which uses a third antenna signal combined mathematically to recover some of the missing phase information. Arranged in a triangle of projected baselines the phase errors cause equal but opposite phase shifts in ajoining baselines, canceling out in the "closure phase". The MIT Haystack groups managed to resolve individual sunspots groups moving across the solar disk using with the technique with the VSRTs.

"An interferometer is an instrument that combines two signals (normally from two detectors) in a manner that the signals interfere to produce a resultant signal. The resultant signal is usually the vector sum of the two signals, but in some cases it is the product or some other mix. The traditional interferometer, usually studied and analyzed in physics courses, combines the two signals in a way that both amplitude and phase information are used. By varying the positions of the two detectors, it is possible to synthesize an effective aperture that is equivalent to the separation of the detectors and to reconstruct the impinging wavefront, thus providing significant information about the extent and structure of the signal source. The traditional phase-sensitive interferometer requires retention of the signal phase at each detector – the phase-sensitive interferometry technique will not be discussed in detail here."

"A special case of the interferometer is the intensity interferometer, which performs an intensity correlation of signals from the two detectors. Although in the intensity interferometer the phase information from the two antennas is discarded, the correlation of the two signals remains useful. Aperture synthesis is not practical, but some important source characteristics may be determined."

I think the VSRT is a special case of intensity interferometer where you don't try to align samples by time after recording. Instead you just look for the baseline distance sinc pattern in total power at the beat frequency of the unsynchronized clocks.

prefix + datetime.now().strftime("%Y.%m.%d.%H.%M.%S") + ".log"

• total power modes (tp-modes.grc)
• vsrt_log_timeplot.pl

Who else helped

I consulted with patchvonbraun a lot for the software/gnuradio side. He gave me an example of how to use the WX GUI Stripchart and I would not have guessed I needed to square the values from the beat frequency bins after the first squaring for taking total power. He made a generic simulator for dual free running clocks LNBF intensity interferometers. You don't even need to have an rtlsdr device to run it; only an up to date install of gnuradio. It is an easy way to understand how to do interferometry without a distributed clock signal.

patchvonbraun's: simulated-intensity-interferometer.grc

Physical

With this setup on a 1 meter baseline and a intermediate tuning frequency of 1.6 GHz IF (10700 MHz+(1600 MHz−950 MHz)= 11350 MHz) the main beamwidth would be about 70*(c/11GHz)/1m), or 1.9 degrees. This does not resolve the solar disk (~0.5 deg) during drift scans. I have been told that the magnitude goes down in a SINC pattern as you widen the baseline and approach resolving the source but I will not resolve the sun initially. In the VSRT Memos "Development of a solar imaging array of Very Small Radio Telescopes" a computationally complex way to resolve individual action regions is done with a 3rd dish providing "phase closure" in the array on a slanted north-south baseline in addition to the existing east-west baseline. I try to point my dishes so that the Earth is passing the sun through the beam at ~12:09pm (noon) each day. To aid in pointing a cross of reflective aluminum tape is applied center of the dish. This creates a cross of light on the LNBF feed when it is in the dish focal plane and the dish is pointed at the sun. The picture below is from later in the day, the one of the left shows the sun drifting out of the beam as it sets. I made my LNBF holders out of small pieces of wood compression fit in the dish arm. There are grooves for the RG6 coax to fit ground out with a rotary tool. The PVC collars have slots cut in the back with screws going into the wood to set the angle.

The screenshot shows a short run near sunset on an otherwise cloudy day. The discontinuities are me running outside and manually re-pointing the dishes. But it does highlight how the beat frequency of the 2 LNBF varies as they warm up when turned on. It starts down at ~90 KHz but within 10 minutes it rises to ~115 KHz. After it reaches equilibrium the variation is ~ -+1 KHz. I could change the existing 80-120 KHz bandpass to a 110-120 KHz bandpass and have better sensitivity. But that bandwidth is something that has to be found empirically with each LNBF pair and set manually within the GUI for now.

patchvonbraun said it was feasible to identify the frequency bins with the most counts and that there was an example within the simpla_ra code,

"You could even have a little helper function, based on a vector probe, that finds your bin range, and tunes the filter appropriately."

The below close up of indoor testing showing how everything is connected on the rtlsdr side showing the power injector, e4k based rtlsdr (wrapped in aluminum tape), and the stripline based satellite power combiner for correlation. The two rg6 quadshield coaxial lines going from the power combiner to the ku band LNBF are as close to the same length as I could trim them. I use a 1 amp 18v power supply and coaxial power injector to supply power to the LNB and any amplifiers. This voltage controls linear polarization (horiztonal/vertical) and it can be changed by putting a few 1 amp 1N4007 in series with the power line to drop the voltage.

Accessory scripts.

tp-modes.grc produces binary logs that are pretty simple. The count of the LNBF beat frequency bins in the bandpass are saved as floats represented as 4 pairs of hexadecimal. When the integration time is set to the default 1 second then one 4 byte data point is written to the log every 0.5 seconds. I highly recommend not changing this for now. There is no metadata or padding. Here's a screenshot of a run using the utility "bless",

In order to convert the binary logs of 4 byte records into something gnuplot can parse I use a simple perl script,

#!/usr/bin/perl
use warnings;
use strict;

my $data = '/home/superkuh/vsrt_2013.06.13.12.26.47.log';
my $bytelength = 4; 
my $format = "f"; # floats (little endian)
my $num_records;

if ($ARGV[0]) {
	$data = $ARGV[0];
} else {
	print "you need to pass the log file path as an argument.";
	exit;
}

open(LOG,"$data") or die "Can't open log.\n$!";
binmode(LOG);

my $i = 0;
until ( eof(LOG) ) {
	my $record;
	my $decimal;
	read(LOG, $record, $bytelength) == $bytelength
		or die "short read\n";
	$decimal = unpack($format, $record);
	printf("$i,\t$decimal\n", $decimal);
	$i++;
}

Now I have the filename which gives the time the gnuradio-companion grc file started running. This is not the time I hit the record button and started logging. The offset is a second or two. Ignoring that, it is possible to use the start time encoded in the log file name to figure out when a particular measurement was taken. To do that I have to know the interval between entries saved to the binary log.

$ date && ls -l /home/superkuh/vsrt_2013.06.14.12.03.00.log && sleep 60 && date && ls -l /home/superkuh/vsrt_2013.06.14.12.03.00.log
Fri Jun 14 13:05:24 CDT 2013
-rw-r--r-- 1 superkuh superkuh 29644 2013-06-14 13:05 /home/superkuh/vsrt_2013.06.14.12.03.00.log
Fri Jun 14 13:06:24 CDT 2013
-rw-r--r-- 1 superkuh superkuh 30124 2013-06-14 13:06 /home/superkuh/vsrt_2013.06.14.12.03.00.log

((30124−29644)/4)/60 = 2

$ date && ls -l /home/superkuh/vsrt_null.log && sleep 60 && date && ls -l /home/superkuh/vsrt_null.logFri Jun 14 13:44:36 CDT 2013
-rw-r--r-- 1 superkuh superkuh 8 2013-06-14 13:44 /home/superkuh/vsrt_null.log
Fri Jun 14 13:45:36 CDT 2013
-rw-r--r-- 1 superkuh superkuh 488 2013-06-14 13:45 /home/superkuh/vsrt_null.log

((488−8)/4)/60 = 2

To know what time a log record corresponds to, take the time from the filename and then add 0.5 seconds * the index of the 4 byte entry in the binary log. This should be possible to write into the until loop so it outputs time instead of just index $i. The below example is a hacky version of my log parser that does just this. Here's an example output.

# UTC Epoch	# Beat Freq Bins
1371229380.0,	1.38292284646013e-06
1371229380.5,	1.37606230055098e-06
1371229381.0,	1.374015937472e-06
1371229381.5,	1.366425294691e-06
1371229382.0,	1.35845414206415e-06
1371229382.5,	1.36476899115223e-06
1371229383.0,	1.36480070977996e-06
1371229383.5,	1.36444589315943e-06
1371229384.0,	1.35775212584122e-06
1371229384.5,	1.36395499339415e-06
1371229385.0,	1.35322613914468e-06
1371229385.5,	1.36412847950851e-06
1371229386.0,	1.36531491534697e-06
1371229386.5,	1.3664910056832e-06
1371229387.0,	1.36144888074341e-06
1371229387.5,	1.35596496875223e-06
1371229388.0,	1.35830066483322e-06
1371229388.5,	1.3654090480486e-06
1371229389.0,	1.358990175504e-06
1371229389.5,	1.37098015784431e-06
1371229390.0,	1.387945303577e-06
1371229390.5,	1.38286770834384e-06
1371229391.0,	1.36734763600543e-06
1371229391.5,	1.36036248932214e-06
...

#!/usr/bin/perl
use DateTime;
use warnings;
use strict;

# The simplest possible gnuplot plot using this program's output.
# ./vsrt_log_timeplot.pl /home/superkuh/vsrt_2013.06.14.12.03.00.log > whee2.log
# gnuplot> plot "./whee2.log" using 1:2 title "VSRT Test" with lines

my $data = '/home/superkuh/vsrt_2013.06.13.12.26.47.log';
my $bytelength = 4; 
#my $format = "V"; # oops, not this unsigned 32 bit (little endian)
my $format = "f"; # float
my $num_records;

if ($ARGV[0]) {
	$data = $ARGV[0];
} else {
	print "you need to pass the log file path as an argument.";
	exit;
}

my $dt; # declare datetime variable globally
extracttime($data); # $dt now has date object.

open(LOG,"$data") or die "Can't open log.\n$!";
binmode(LOG);

my $i = 0;
until ( eof(LOG) ) {
	my $record;
	my $decimal;
	read(LOG, $record, $bytelength) == $bytelength
		or die "short read\n";

	$decimal = unpack($format, $record);

	# This is a stupid/fragile way to deal with datetime
	# not having enough precision. It only works if the
	# record to record interval is always 0.5 seconds.
	my $recordtime = $dt->epoch();
	if (0 == $i % 2) {
		printf("$recordtime.0,\t$decimal\n", $decimal);
	} else {
		printf("$recordtime.5,\t$decimal\n", $decimal);
	}

	$dt->add( nanoseconds => 500000000 );
	$i++;
}

sub extracttime {
	my $timestring = shift;
	# /home/superkuh/vsrt_2013.06.13.12.26.47.log
	$timestring =~ /(\d{4}\.\d{2}\.\d{2})\.(\d\d\.\d\d\.\d\d)/;
	my $year_month_day = $1;
	my $time = $2;

	my ($year,$month,$day) = split(/\./, $year_month_day);
	$time =~ s/\./:/g;
	my ($hour,$minute,$second) = split(/:/, $time);

	$dt = DateTime->new(
		year       => $year,
		month      => $month,
		day        => $day,
		hour       => $hour,
		minute     => $minute,
		second     => $second,
		time_zone  => 'America/Chicago',
	);

	$dt->set_time_zone('UTC');
	return 1;	
}

Now I just have to make up a good gnuplot format and integrate the calls into the perl script.

Computer controlled pointing, mechanical and software differences

Manually repositioning the dishes swamps out the signal of interest as the target leaves the beamwidth. For any decent measurements I need computer controlled pointing. This means the Haystack idea of two coupled Diseqc 1.2 compatible motor positioners mounted one on the other. In their design both dishes are mounted on a single PVC tube hooked to one of the positioners with a metal extension. My satellite dish mounts can't rotate like theirs so I'll have to modify this design a bit. They use a serial relay to "push" the buttons on a physical Diseqc 1.2 motor controller remote. That seemed a bit convoluted to me. I bought a SkyStar2 DVB-S pci card and under linux send raw Diseqc commands out by calling xdipo which accesses the linux DVB interface. It has both a GUI and cli interface. Unfortunately xdipo cannot send through Diseqc switches. I had to add manual motor commands to tune-s2 which did support switches but not manual motor commands. This version which supports manual stepping mode is available at https://github.com/superkuh/tune-s2-stepping.

Another alternative Diseqc motor controller I didn't persue would be using a 192 KHz USB soundcard and the DiSEqC Audio Generator software from Juras-Projects. The documentation for the hardware side of the audio generator is 404 now, but Juras responded to an email of mine with the schematics attached.

Since the bent motor shafts that came will my motors looked really difficult to drill through I thought I'd use straight hex holed shafts to make everything mechanically simpler. I found http://www.reidsupply.com/sku/HHS-18/ and ordered a couple. Unfortunately my measurements of the dish motor shaft flat-to-flate size were off. The Reid hex holed shaft hole is just a tiny bit too large. This was easily fixed by wrapping a couple turns of masking tape around the shaft to increase the diameter. This is often how fishing rod handles are made. I also encountered this construction technique on Jarrod Kinsey's CO2 laser pages.

The hardest part of all this is drilling an 8mm hole precisely normal to the curved outside surface of the hex hole shaft. The first step is to flatten the area with a hand file. This took me about 10 minutes. I had previously ordered and received two carbide drill bits, one small to sub-drill the intial hole and then one 8mm for the final hole. A drill press and small vice are quired to actually drill the holes. And even then it's really tricky. My first two attempts resulted in holes not quite normal to the surface of the hex flat. I could only use roll or taper pins to secure the shaft. Luckily I bought 2x shafts just in case.

I also had to drill 4 additional 8mm holes in the 2x satellite dish motor mounts to make holes for level mounting instead of at a tilt. The VRST guys got lucky with their sat motor mounts having a long slot.

The diameter of easily available PVC is slightly to small for the dish mounting clamp. This is remedied like the motor shafts; by wrapping wide masking tape to size and optionally epoxy coating/sanding it.

The dish motors used in the VSRT project were Stab HH90. These have come down in cost since the VSRT memos were written and are still widely available.

 065	Stab HH90 dish pointing motor #1
 065 	Stab HH90 dish pointing motor #2
$130 total

In order to control these motors a system to send DISEqC 1.2 commands is needed. The first option would be to faithfully replicate the VSRT implementation. They do it in a rather roundabout way but at least it is tested and known to work with their software. Unfortunately the specific hardware used has become rare, is mostly shipped from overseas, or is expensive.

 045	STAB MP01 Positioner Control #1
 045	STAB MP01 Positioner Control #2
 080	WTSSR-M Serial port Solid State Relay 
 000	VSRT Java software (windows)

 030	Two 5" x 9" x 0.125" thick steel plates
 020	Two 15" x 1" x 0.125" thick aluminum counterweight arms
 020	Shipping for the metal parts.

My chosen method of HH90 motor control is a single DVB-S card under linux with DVB API 5.x w/ my modified tune-s2 and optionally xdipo. This can be combined with a DiSEqC switch to scale to control of multiple motors relatively cheaply. I do sun alt-az position calculation by using a small pysolar python script. I have not yet completed the scripts to turn alt-az positions of the sun at my location into motor step commands. Hopefully I can use some of the USAL fuctions in tune-s2 for that.

 066	Skystar 2 HD pci card
 010	DiSEqC switch
 000	tune-s2 and xdipo DVB control software (linux)

 020	.753" Hex-Holed Sleeve
 010	5" wide masking tape
 020	Two 15" x 1" x 0.125" aluminum counterweight arms

Both require PVC pipe, tools like drills, 8mm drill bits and smaller sub-drill bit, hand saws, files, and potentially a welder (though liberal J-B Weld would probably work).

Diseqc switches problems and solutions.

It turns out that xdipo alone cannot deal with motors behind Diseqc switches. This means it can only control one Diseqc motor at once. Controlling two would require 2x Skystar 2 pci cards. Luckily there are other options. CrazyCat's tune-s2 supports Diseqc switches and addressing. It normally only provides for motor commands using the USAL system which isn't too helpful. But I was able to modify the code to support manual motor position commands while retaining the switch support. xdipo could still be used in theory by calling tune-s2 to set the Diseqc switch to the appropriate port/motor and then calling xdipo as normal. But it is easier to just use the modified tune-s2 for everything.

This gutted version of tune-s2 for manual motor commands is available at:

https://github.com/superkuh/tune-s2-stepping

The functions I added are basically just look up arrays with Diseqc bus commands for different steps in the clockwise or counter-clockwise directions. In Diseqc the packets have 4 sections. Check out the Diseqc Bus Functional Specification (pdf) for a better explanation with more detail.

The first, "Framing" byte represent if the command is from the receiver or diseqc device and wether it needs a reply. For my table these are all just "EO" which means it's a packet from the receiver with no response required. Most commands are EO but it goes up to E7.

The second, "Address" specifies which types of Diseqc devices should listen (ex: LNB, switch, motor, polarizer). For motors this is "32"

The third is "Command". This is a huge list of values of which only "68" and "69" are relevant. They are "Drive Motor East" and "Drive Motor West" respectively. The "Command" byte is only relevant to their specific devices specified via the "Address" byte.

The remaining bytes of the packet are "Data" and how they're interpreted depends on the "Command" bytes specifying a specific type of command. For motor movement there are three options. "00" makes the motor turn until a Diseqc stop command is sent. The second mode is positive values for the bytes, "01" to "7F". They represent an amount of time to turn the motor. Or by specifying negative byte values "80" to "FF" the motor is rotated a number of steps. This last is best and detailed in the Positioner Application Note (pdf) with an excerpt below,

The number of steps to make is given by the additional count needed to make the parameter byte reach zero (or overflow to zero if the byte is considered as unsigned). Thus the byte 'FF' (hexadecimal) requests only one step, 'FE' two steps, and for example 'F9' requests 7 steps.

With my motors each step corresponds to about 0.1 deg. Using this information I made up a table of Diseqc packets for each rotation direction.

struct dvb_diseqc_master_cmd step_east[] =
{
	{ { 0xe0, 0x31, 0x68, 0xFF, 0x00, 0x00 }, 4 },  // Drive Motor West 1 step
	{ { 0xe0, 0x31, 0x68, 0xFE, 0x00, 0x00 }, 4 },  // Drive Motor West 2 step
	{ { 0xe0, 0x31, 0x68, 0xFD, 0x00, 0x00 }, 4 },  // Drive Motor West 3 step
	{ { 0xe0, 0x31, 0x68, 0xFC, 0x00, 0x00 }, 4 },  // Drive Motor West 4 step
	{ { 0xe0, 0x31, 0x68, 0xFB, 0x00, 0x00 }, 4 },  // Drive Motor West 5 step
	{ { 0xe0, 0x31, 0x68, 0xF6, 0x00, 0x00 }, 4 },  // Drive Motor West 10 step
	{ { 0xe0, 0x31, 0x68, 0xEC, 0x00, 0x00 }, 4 },  // Drive Motor West 20 step
	{ { 0xe0, 0x31, 0x68, 0xE2, 0x00, 0x00 }, 4 },  // Drive Motor West 30 step
	{ { 0xe0, 0x31, 0x68, 0xD8, 0x00, 0x00 }, 4 },  // Drive Motor West 40 step
	{ { 0xe0, 0x31, 0x68, 0xCE, 0x00, 0x00 }, 4 },  // Drive Motor West 50 step
	{ { 0xe0, 0x31, 0x68, 0x9C, 0x00, 0x00 }, 4 }   // Drive Motor West 100 step
};

struct dvb_diseqc_master_cmd step_west[] =
{
	{ { 0xe0, 0x31, 0x69, 0xFF, 0x00, 0x00 }, 4 },  // Drive Motor West 1 step
	{ { 0xe0, 0x31, 0x69, 0xFE, 0x00, 0x00 }, 4 },  // Drive Motor West 2 step
	{ { 0xe0, 0x31, 0x69, 0xFD, 0x00, 0x00 }, 4 },  // Drive Motor West 3 step
	{ { 0xe0, 0x31, 0x69, 0xFC, 0x00, 0x00 }, 4 },  // Drive Motor West 4 step
	{ { 0xe0, 0x31, 0x69, 0xFB, 0x00, 0x00 }, 4 },  // Drive Motor West 5 step
	{ { 0xe0, 0x31, 0x69, 0xF6, 0x00, 0x00 }, 4 },  // Drive Motor West 10 step
	{ { 0xe0, 0x31, 0x69, 0xEC, 0x00, 0x00 }, 4 },  // Drive Motor West 20 step
	{ { 0xe0, 0x31, 0x69, 0xE2, 0x00, 0x00 }, 4 },  // Drive Motor West 30 step
	{ { 0xe0, 0x31, 0x69, 0xD8, 0x00, 0x00 }, 4 },  // Drive Motor West 40 step
	{ { 0xe0, 0x31, 0x69, 0xCE, 0x00, 0x00 }, 4 },  // Drive Motor West 50 step
	{ { 0xe0, 0x31, 0x69, 0x9C, 0x00, 0x00 }, 4 }   // Drive Motor West 100 step
};

For addressing specific ports of the Diseqc switch tune-s2's normal functions are used. They are called before the motor position commands are sent. Usage of the modified tune-s2 is pretty simple. The only differences are two new cli switches and not needing to give it tuning parameters.

-step-east 
-step-west

./tune-s2 -step-west 0 -committed 1

This would cause the satellite dish motor on port 1 of the Diseqc switch to step 1 position counter-clockwise. To send the same command of stepping 1 position counter-clockwise to the other motor,

./tune-s2 -step-west 0 -committed 2

The stepping argument values 0 through 10 are mapped on a fairly arbitrary set of actual steps. This results from just doing array index look ups in the above packet tables,

0->1
1->2
2->3
3->4
4->5
5->10
6->20
7->30
8->40
9->50
10->100

http://www.satnigmo.com/2254/how-to-configure-emp-centauri-diseqc-switches/

Calculating solar position and using that to decide how many steps to step per axis

Figuring out where the sun is in the sky in terms of an alt-az format is made simple by pysolar. Figuring out how to turn that position into sequences of steps on the motors is much, much harder.

#! /usr/bin/env python
import Pysolar
import datetime
d = datetime.datetime.utcnow()
lat = 40.0
long = -90.0
sol_alt = Pysolar.GetAltitude(lat, long, d)
sol_long = Pysolar.GetAzimuth(lat, long, d)
print sol_alt
print sol_long

These values are relative to the pysolar reference frame which is given by their diagram,

$ ./solpos.py 
41.4925424732
-35.8472087363

My setup is pointed directly south. So for this example time that means I need to calculate the number of steps required to turn the (top) altitude motor 41.5 up from level and the (bottom) azimuth motor 35.8 degrees to the left (east).

The hardest part of this is figuring out what kind of pager system you have. I spent a long time trying to decode the local FLEX pager system with decoders that did not support it.

Written by Thomas Sailer, HB9JNX/AE4WA, multimon (multimon.tar.bz2) supports decoding a large number of pager modulations. FLEX is not one of them. Scroll down for FLEX.

On June 29th 2012 dekar told me about his updated fork of multimon, multimonNG, with better error correction and more modulations supported. As of right this instant those on 64bit linux should just use the existing makefile and *not* qmake or qt-creator to compile it. For the windows users (or anyone wanting more info) there's a precompiled version and blog post. Make sure to disable all the demodulators you don't need. I think especially ZVEI is quite spammy. This and this is what pocsag sounds like if you're wondering.

When I originally started playing and wrote this there were only a couple options for rtlsdr receivers to use with the multimon decoder. I used patchvonbraun's multimode to save .wavs and dekar's pager example GRC I modified for OsmoSDR sources linked below for raw, real time decoding. Lately (as of late 2012/13) a large number of receivers have been released that don't depend on GNU Radio. rtl_fm is one and there's an example usage below.

real time decoding rtl_fm

rtl_fm -f 930.353e6 -g 100 -s 22050 -l 310 - |multimon -t raw -a POCSAG512 -a POCSAG1200 -a POCSAG2400 -f alpha /dev/stdin

Dekar's multimonNG, a fork with improved error correction, more supported modes, and *nix/osx/windows support. In the screenshots below the signal is not pocsag. I thought it might be zwei but now I'm not so sure it's even pager data. Test samples of pocsag that Dekar links on his blog decode just fine.

mkfifo /tmp/pager_fifo.raw
./multimonNG -t raw /tmp/pager_fifo.raw
gnuradio-companion pager_fifo_web.grc

In order to decode the pager data in real time you should use a first-in first-out file (fifo). Dekar's pager_fifo is designed to do that but you'll need to set the correct file paths for the File Sink yourself. In the copy downloadable here the File Sink's path is set to "/tmp/pager_fifo.raw". You should be able to run it without editing once you've made that fifo. Make sure to start multimon reading the fifo before you begin GRC and execute the receiver.

In my personal copy of dekar's pager_fifo the file and audio sinks are enabled while the waterfall, wav, and other sinks are disabled. To enable the disabled (grey) block select them and press 'e' ('d to disable). The audio sink is set to pulseaudio ("pulse").

Unfortunately it turned out my local pagers were all using FLEX, and so not supported by any of the above software. But the procedures might still be useful for someone. Decoding FLEX can be done with the software PDW, but it is windows only. In GNU Radio there is additionally gr-pager, which is supposed to support flex, but many implementation scripts for it are GNU Radio 3.6.5 or older and getting stuff to work with 3.7 requires namespace changes. mothran's flex_hackrf is one of these. Since the rtlsdr receivers can but shouldn't do 3.125 MS/s, like flex_hackrf of uhd_flux, what they use natively for the bandwidth, and so decimation, and pretty much everything else have to be re-written too. I've attempted to start this and you can see a copy here.

A couple days after I wrote the above paragraph zarya came on ##rtlsdr on freenode and mentioned his rtlsdr supprting FLEX decoder written months before. It is easy to use and works great! This script runs at a 250 KS/s sample rate and decodes 12.5 KHz channel only. Internally it uses gnuradio's optfir to generate low pass taps that wide to use witih a frequency xlating FIR filter. It then passes that to gr-pager's flex_demod.

later: argilo (Clayton Smith) has also put together an osmosdr source based gr.pager flex decoder for his GNU Radio tutorial series.

The below output is heavily censored and edited to avoid disclosing or reproducing sensitive information but it gives you an idea of the type of messages.

git clone https://github.com/zarya/sdr
cd sdr/receivers/flex/
./rtl_flex_noX.py -f 929.56M --rx-gain=37.2
linux; GNU C++ version 4.6.3; Boost_104800; UHD_003.005.004-149-gc357a16e

No database support
gr-osmosdr v0.1.0-33-g8facbbcc (0.1.1git) gnuradio 3.7.2git-123-g0ded5889
built-in source types: file fcd rtl rtl_tcp uhd hackrf netsdr 
Using device #0 Generic RTL2832U SN: 77771111153705700
Found Rafael Micro R820T tuner
Exact sample rate is: 250000.000414 Hz

Setting gain to 20.700000 (from [0.000000, 49.600000])
Using Volk machine: avx_64_mmx_orc
0 929.560|        55|SPN|2900
0 929.560|   5555555|ALN|osoft JDBC type 4 driver for MS SQL Server 2005:FreePoolSize = 24  [03]
0 929.560|       555|ALN|MSN 020 hello Message from NOC PCB. 129       
0 929.560|   5555555|ALN| Task: 3322391 Net: 0 Pressman: REDACTED, REDACTED Click here to view the curre [28]
0 929.560| 555555555|ALN|4.Q!T .(-RS(7+*# ~A-!lu+3L:REDACTED:YSGO>T JL*qN>][WOA"$(0?"$8QB, 33*dM:YSG.>][WO<]\(0BK [1
0 929.560|   5555555|ALN|From: REDACTED@REDACTED.com Subject: REDACTED scheduled report: "05:00 Medication Devices" - Scheduled report "05:00 Medication Devices" was sent by REDACTED. <>  [43]
0 929.560|   5555555|ALN|re| 7291 W 190th St| FD o/s calling a 2nd alarm for a structure fire, Setting up water supply| REDACTED008| 05:02 . .   [97]
0 929.560|   5555555|ALN|Fr/m: 7th.Floor-.REDACTED REDACTED: +Blood Cultures; G+ cocci from yesterday's clinic draw. On Cefepime. Afebrile. New orders? Draw BCs in am? [31]
0 929.560|   5555555|SPN|766087U410 5[[[
0 929.560|   5555555|ALN|REDACTED, REDACTED 9105-2 FYI: Notified by lab stool sample came back positive of C.diff Liculda, RN REDACTED c9q [74]..

I tried for over a year before successfully decoding local pager signals. Now that I have I think it is a bad idea. There is far much too much private information in cleartext. I don't plan to try again.

Read this person's guide instead.

When I wrote this up the original version by csete didn't support the hardware yet but mathis_, phirsch, Hoernchen, and perhaps others I've missed from ##rtlsdr on freenode had added librtlsdr support to gqrx; their repos are still listed by commented out. These days csete has added in rtlsdr support so you can use his original repository.

git clone https://github.com/csete/gqrx.git
cd gqrx 
# on Ubuntu, sudo apt-get install qtcreator , if you don't have it.
qtcreator gqrx.pro 	# press the build button (the hammer)
# Avoid qtcreator doing it manually.
qmake
make

./gqrx

/home/superkuh/app_installs/gnuradio/gqrx/gqrx/qtgui/dockaudio.cpp:100: error: ‘currentDateTimeUtc’ is not a member of ‘QDateTime’

To get it to compile on these systems you'll have to do the below. (edit: This little change is now added into phirsch's.)

Ubuntu 10.04 has old Qt libs and gqrx uses a function call not in them. So, while I was waiting for Qt 4.74 to compile I decided to try a hack. I removed that function call with a static string of text. [edit] I later found comparable functions for Qt 4.6 and older.

If you are using qtcreator like the docs suggest you can double click on the error and go to the line. If not, it was in ./Sources/qtgui/dockaudio.cpp replace,

void DockAudio::on_audioRecButton_clicked(bool checked)
{
    if (checked) {
        // FIXME: option to use local time
        lastAudio = QDateTime::currentDateTimeUtc().toString("gqrx-yyyyMMdd-hhmmss.'wav'");

With something like this.

void DockAudio::on_audioRecButton_clicked(bool checked)
{
    if (checked) {
        // FIXME: option to use local time
        // use functions compatible with older versions of Qt.
        lastAudio = QDateTime::currentDateTime().toUTC().toString("gqrx-yyyyMMdd-hhmmss.'wav'");

And it'll compile and run correctly on my specific machine.

Compiling LTE Cell Scanner and LTE Tracker on Ubuntu 10.04

Before starting make sure to have a fortran compiler, FFTW, BLAS, and LAPACK libraries installed from the repositories.

sudo apt-get install automake autoconf libtool libfftw3-3 libfftw3-dev gfortran libblas3gf libblas-dev liblapack3gf liblapack-dev libatlas-base-dev

If you're using 12.04 just follow the instructions on the github page and everything is trivial. For 10.04 (lucid) users the the initial hurdle is cmake. LTE Cell Scanner requires cmake 2.8.8 and Ubuntu 10.04 only has 2.8 the finding of BLAS and LAPACK libraries will fail like,

CMake Error at CMakeLists.txt:1 (CMAKE_MINIMUM_REQUIRED):
  CMake 2.8.4 or higher is required.  You are running version 2.8.0.

Until you open CMakeList.txt and change the version number on first line to 2.8.0. After fixing that the BLAS and LAPACK issues come in,

cmake ..
-- Found ITPP: /usr/lib64/libitpp.so
CMake Error at /usr/share/cmake-2.8/Modules/FindBLAS.cmake:45 (message):
  FindBLAS is Fortran-only so Fortran must be enabled.
Call Stack (most recent call first):
  CMakeLists.txt:29 (FIND_PACKAGE)

You can see my installation notes before I figured it out. To fix it I searched for people complaining of similar problems on other projects and then replaced my *system* files with theirs, FindBLAS.cmake.

sudo cp /usr/share/cmake-2.8/Modules/FindBLAS.cmake /usr/share/cmake-2.8/Modules/FindBLAS.cmake.bak 
sudo cp FindBLAS.cmake /usr/share/cmake-2.8/Modules/

LAPACK will also fail this way. I used this arbitray cmake file, http://code.google.com/p/qmcpack/source/browse/trunk/CMake/FindLapack.cmake?r=5383. And this is a local backup in case that disappears.

sudo cp /usr/share/cmake-2.8/Modules/FindLAPACK.cmake /usr/share/cmake-2.8/Modules/FindLAPACK.cmake.bak
sudo FindLAPACK.cmake /usr/share/cmake-2.8/Modules/FindLAPACK.cmake

After fixing the cmake issues compile and install the latest IT++ (ITPP 4.2). Make sure to completely remove the old ITPP 4.0.7 libraries from the Ubuntu repository. When LTE Cell scanner compiles you can go back and restore the .bak cmake files. The rate of scan is about 0.1 Mhz per 10 seconds.

./CellSearch -v -s 751e6 -e 751e6
LTE CellSearch v0.1.0 (release) beginning
  Search frequency: 751 MHz
  PPM: 100
  correction: 1
Found Elonics E4000 tuner
Waiting for AGC to converge...
Examining center frequency 751 MHz ...
Capturing live data
  Calculating PSS correlations
  Searching for and examining correlation peaks...
  Detected a cell!
    cell ID: 414
    RX power level: -17.0733 dB
    residual frequency offset: 43592.8 Hz
  Detected a cell!
    cell ID: 415
    RX power level: -20.8041 dB
    residual frequency offset: 43592.3 Hz
  Detected a cell!
    cell ID: 209
    RX power level: -28.8524 dB
    residual frequency offset: 43581.2 Hz
Detected the following cells:
C: CP type ; P: PHICH duration ; PR: PHICH resource type
CID      fc   foff RXPWR C nRB P  PR CrystalCorrectionFactor
414    751M  43.6k -17.1 N  50 N one 1.0000580496943698439
415    751M  43.6k -20.8 N  50 N one 1.0000580490797574829
209    751M  43.6k -28.9 N  50 N one 1.0000580342133056355

Both positive and negative frequency offsets happen, but rarely in the same dongle.

LTE Tracker I haven't used as much yet (recently released) but it is included in the github repository cloned initially and should be compiled as well if you did the above. Check out the authors site for videos of it's use since an ascii paste of the ncurses like interface wouldn't tell you much. But... the start looks like this,

./LTE-Tracker -f 751e6
LTE Tracker v1.0.0 (release) beginning
  Search frequency: 751 MHz
  PPM: 120
  correction: 1
Found Rafael Micro R820T tuner
Calibrating local oscillator.
Calibration succeeded!
   Residual frequency offset: -48937.5 Hz
   New correction factor: 0.99993484110674779597
Searcher process has been launched.

Tips

If it comes with a python file, try that first before generating one from the GRC file. When tuning, make sure to hit enter again if it doesn't work the first time or tunes to the wrong frequency. Always hit autoscale to start, and for FFT displays try using the "average" settings. I have set all audio sinks to "pulse" (pulseaudio) instead of say, "hw:0,0" (ALSA). You might have to change that. To get a list of hardwareuse "aplay -l". That'll show the various cards and devices. Use the format, "hw:X,Y" where "hw:CARD=X,DEV=Y". Some flowcharts have variables for it, others put it directly in the Audio Sink element. If you hear something interesting you can try comparing it to indentified samples from http://www.kb9ukd.com/digital/ or http://hfradio.org.uk/html/digital_modes.html. or the windows program, Signals Analyzer. Check http://www.radioreference.com/ or http://wireless2.fcc.gov/UlsApp/UlsSearch/searchAdvanced.jsp to see what's in the USA area at a given frequency.

Multiple Dongles

There are two ways to specify the use of multiple dongles. The first, correct, way is to set the "Num Channels" in the OsmoSDR Source block to "2" and then specify the device IDs in "Device Arguments" like, "rtl=0 rtl=1". Each specified device is seperate with a space from the previous one.

The not so correct but still working way is to use multiple OsmoSDR Source blocks with "Num Channels" set to "1" and each with it's respective "Device Arguments" field set to "rtl=0" or "rtl=1", or so on.

The OsmoSDR Source block has extensive help files at the bottom of it's properties if you scroll down.

Editing

To enable a block, select it and press 'e'. To disable a block select it and press 'd'. When disabled blocks will appear darker gray.

If you open a .grc file and it looks like there are blocks missing (red error highlights and no connections between them) then it is likely the name of the block changed during some GNU Radio update. If your install is more than a month or two old this often happens. Update GNU Radio.

It's easier to type in 1e6 than 1000000 so use scientific notation when you can in variable fields. If you double click on an element in a flowchart it usually includes a helpful "Documentation:" of most the variables to be set at the bottom. The GUI element grid position is a set of two pairs of numbers: "y,x,a,b" where the first pair "y,x," is position (y row, x column) and "a,b" is the span of the box. If you enter a Grid Position and it overlaps with another element it'll turn red and report the error and where the origin is of the element it overlaps with.

Use the Grid Position (row, column, row span, column span) to position the graphical element in the window.

The tab effect is done with notebooks.

For RTL2832 Source the minimum sample rate is ~800KS/s, it's gr-baz(?) and generally not updated. Use OsmoSDR source. It's under "OsmoSDR", not "Sources" on the right panel). It has a 1MS/s minimum sample rate. It's not recommended to use sample rates above 2.4M.

In older versions of gr-osmosdr and rtl-sdr I think automagic gain control (AGC) was on all the time so you didn't have to set the gain explicitly in the source in GRC. New versions require that and also require setting the chan 0. freq to something.

The dongles seem to have noise at their 0Hz center frequency so the best performance is from selecting a band 100-200Khz offset from the center (depending on signal type). patchvonbraun's simple_fm_rcv is a great example of that.

(this summary is outdated) The best sounding software I've found for listening to FM is patchvonbraun's Simple FM (Stereo) Receiver. I don't think it is very simple; it includes many advanced FM specific features like extraction of the 19k (pilot) tone next to some commercial FM broadcasts. It used to do RDS, I hear, and older versions checked into CGRAN still have it, but it is removed for simplicitly in this version.

svn co https://www.cgran.org/svn/projects/simple_fm_rcv
cd simple_fm_rcv/
cd trunk
less README
make
make install
## it'll install to ~/bin/, so I use ~/superkuh/bin below
set PYTHONPATH=/usr/local/lib/python2.6/dist-packages:/home/superkuh/bin
# run the python script
python simple_fm_rcv.py
# or edit it
gnuradio-companion simple_fm_rcv.grc

Original: http://lindi.iki.fi/lindi/gnuradio/rtl2832-cfile-lindi-fm.grc , this was an example posted to ##rtlsdr by lindi. It used a file source which was decoded to wav and saved to disk. Seen in the screenshot above.

Modified: http://superkuh.com/rtl2832-cfile-lindi-fm_edit.grc , had a frontend GUI and an increased sample rate. Right now the rate of the audio files saved out is... not very useful. But it sounds fine. Seen below.

3.2 MS/s field of view, tune +-900Khz

2h20 made available, with thorough explaination, a bare bones FM (mono) receiver to learn how to use GNU Radio. This was the first one I managed to get to work. Because the original h202's uses the RTL2832 Source and not the OsmoSDR Source you might experience tuner crashes if you scan too quickly. Make sure to un/replug in the dongle after these. It's best just to enter the frequency as a number.

[Be aware this section of this page was written many months ago when rtl-sdr was different and I had little idea of what I was doing. xzero has since manually added signal seeking to this example.]

My edit of 2h20's simple receiver does not add much, but I did replace the RTL2832 source with an OsmoSDR source to avoid tuner crashes. I also increased the sample rate to 2.8MS/s (to see more spectrum) and then increased the decimation in the filter from 4 to 8 to compensate so everything still decodes/sounds right. I also remove the superfluous throttle block.

• Modified 2h20's Mono FM Receiver (.grc)

This takes parts from a bunch of the other example receivers and repurposes them in presumably incorrect but seemingly working ways. It is a basic example of how to offset the tuner 200khz away from the center to avoid the noise there. I started with 2h20's simple tuner's GUI framework and removed almost all of the content. I copied, with inaccurate trial and error changes of sample rate and filter offset, sections of the offset tuning and other advanced bits from simple_fm_rcv and wfm_rx.grc. The tuner is tuned +200Khz. The freq_xlating filter is tuned +200Khz. The the bandpass filter is specified in a variable,

firdes.complex_band_pass(1.0,1.024e6,-95e3,95e3,45e3,firdes.WIN_HAMMING,6.76)

The net result is that the frequency of interest comes out of the tuner 200Khz below DC, and the freq_xlater "lifts it up" by 200Khz, and then it's bandpassed.

I also blindly copied the RF power display, a toggle for saving the audio files out to disk, and a +-900khz tuning slider from other receivers. I added a second 'fine' tune +-50Khz. This is done by setting the frequency of the Xlating FIR filter to,

freq_offset+fine+finer

where freq_offset is the frequency offset from center (200Khz in this case), fine is the ID of a wx gui slider for regular tuning, and finer is the same for fine tuning. In order for the frequency display to show the proper value it was correspondingly set to a variable ID cur_freq,

frequency-fine-finer

I also made the current frequency display a editable text field so you can tune, copy, and paste. There are good examples of how notebook positioning works and includes simple scripting examples for the file field. This flowchart is simple enough to learn from but includes many elements pulled out of the very complex simple_fm_rcv from patchvonbraun. Without his explanation of the offset process I wouldn't have figured it out. All blocks are layed out by type and GUI elements in the same order as they appear when run. This should help you figure out Grid and Notebook positioning.

The sound is only "okay". I think the signal is being clipped off at the edges a little bit. I am not sure if it is required to install patchvonbraun's simple_fm_rcv to use this, I do use some of his custom filter stuff.

Usage

Use the Waterfall for scanning through channels. Once located, look at the offset from 0 on the bottom display. Use that to set the tuning (and fine) slider and wiggle it till you get the signal crossing the band in the "Second Filter" top display. Switch to FFT view and look at the bottom "First Filter" display, use tuning and fine tuning to center the peak on the "First Filter" display. Or the other way around. It's personal preference. Ignore the noise you see at higher frequencies (900Mhz) at +0.2Mhz baseband. Although sometimes it gets folded in depending on tuning.

• superkuh's FM w/offset tuning, fine tuning, and recording (.grc)

Created by Alexandru Csete OZ9AEC the notes say, "Simple SSB receiver prototype". This comes from the GNU Radio GRC examples repository over at https://github.com/csete/gnuradio-grc-examples/tree/master/receiver

git clone https://github.com/csete/gnuradio-grc-examples.git

I changed the way it saves samples for the sister decoder program by adding automatic generation of file names and an on/off tickbox toggle for recording. You might want to change the default directory by editing the variable "prefix". The key was

"/dev/null" if record == False else capture_file

in the File Sink 'file' field. I also changed the GUI so it was easier to find signals. Use the saved .bin files with ssb_rx_play to hear. Jumping around in frequency is a lot smoother when reading from disk instead of the dongle.

• Modified OZ9AEC SSB Receiver (.grc)
• ssb_rx_play (.grc)

# rtlsdr on odroid-u3
sudo /usr/local/bin/root-utility.sh # resize partition first
sudo apt-get update
sudo apt-get upgrade
sudo apt-get -f dist-upgrade
# at this point you'll get a kernel that won't work with lots of modules (like NFS)
# use root-utility.sh again to update the kernel and it'll work.
sudo /usr/local/bin/root-utility.sh
# Install the required programs and libs
sudo apt-get install git cmake libusb-1.0-0 libusb-1.0-0-dev
# For some reason libusb.h didn't get installed so I did it manually
sudo apt-get install unp # to unpack the .deb
apt-get download libusb-1.0-0-dev
unp data.tar.xz
unp libusb-1.0-0-dev_2%3a1.0.17-1ubuntu2_armhf.deb
sudo cp ./usr/include/libusb-1.0/libusb.h /usr/include/libusb-1.0/libusb.h
# Then I could start compilation of rtlsdr
git clone git://git.osmocom.org/rtl-sdr.git
cd rtl-sdr/
mkdir build
cd build
# The lib dir is for odroid-u3 weirdness. The _FILE_OFFSET_BITS is for writing >2GB files without pipes.
cmake ../ -DCMAKE_INSTALL_PREFIX=/usr -DINSTALL_UDEV_RULES=ON -DLIB_DIR=/usr/lib/arm-linux-gnueabihf -D_FILE_OFFSET_BITS=64
make
sudo make install
sudo su -
ldconfig

#hackrf one on odroid-u3, do all the non-rtlsdr stuff above then,
git clone git://github.com/mossmann/hackrf.git
cd hackrf/host
mkdir build
cd build
# The lib dir is for odroid-u3 weirdness. The _FILE_OFFSET_BITS is for writing >2GB files without pipes.
cmake ../ -DINSTALL_UDEV_RULES=ON -DLIB_DIR=/usr/lib/arm-linux-gnueabihf -D_FILE_OFFSET_BITS=64
make
sudo make install
sudo su -
ldconfig

[comment on this post] Append "/@say/your message here" to the URL in the location bar and hit enter.

Related Pages

• RTLSDR/GNU Radio
• 70-1000 MHz Radio Archive
  • Frequency hopping scans, directory list, an example.
• 11 GHz Interferometer
  • Resources
• Broadband Antenna
• Planar PCB Radio Filters
  • Dual-Coupled Combline Bandstop
  • Stepped Impedance Bandstop
  • Defected Ground Structure Open-Loop and Split-Ring Resonator Bandpasses
  • Tunable Open-Loop Resonator Bandpass
  • Tunable Combline Bandpass
  • Substrated Integrated Waveguide Coaxial Cavity Bandpass