Back in June we posted about DE8MSH’s rtl_power based heatmap viewer which was automatically generated every day from a Raspberry Pi. The browser based heatmap display provides a way to view the frequency and time of where the mouse pointer is allowing you to easily identify signals.
Back then the code was unavailable but now DE8MSH has released his code on GitHub. An example heatmap generated by the code can be found here.
A few months back we posted about how the the RTLSDR-Scanner software had been updated to include signal triangulation capabilities. Now blogger Tobby has written a post about his attempt at triangulating the source of an encrypted police signal with RTLSDR-Scanner.
To do this he set up a laptop in his car with RTLSDR-Scanner installed and connected his RTL-SDR with stock antenna and a GPS receiver. After driving around for only 15 minutes he was able to get a triangulation heat map of reasonable accuracy.
A new instructional page for the rtl_power tool is now available on main author keenerds webpage. Rtl_power is a command line tool for logging wide band frequency power scans to a CSV file. The CSV files can then be used for analysis or to create a large frequency plot image. An example of a 2 GHz+ bandwidth scan over 24 hours is shown below. Rtl_power is available as part of the official osmocom RTL-SDR drivers.
Amateur radio astronomy hobbyist Jim Sky has written on his blog about his new program called RTL Bridge with allows the RTL-SDR to directly connect to his other radio astronomy programs Radio-SkyPipe and Radio-Sky Spectrograph. Jim describes his two existing program as follows.
Radio-Sky Spectrograph displays a waterfall spectrum. It is not so different from other programs that produce these displays except that it saves the spectra at a manageable data rate and provides channel widths that are consistent with many natural radio signal bandwidths. For terrestrial , solar flare, Jupiter decametric, or emission/absorption observations you might want to use RSS.
Radio-SkyPipe is a souped-up strip chart program which plots signal strength over time. When getting its data from RTL Bridge, RSP is plotting the total power in the spectrum covered by the RTL receiver centered around its set frequency. While the raw values are proportional to power, you will have to apply a function via the RSP Equations feature to apply a calibration if you want absolute values. For signals that do not have significant spectral structure of interest, this would be the preferred way to plot the data.
Over on ttrftech’s blog in Japanese (use Google translate), ttrftech has uploaded a new RTL-SDR program for Chrome which allows 3D visualization of the frequency spectrum. The program can be installed by simply downloading the files from GitHub and loading them into Chrome. Ttrftech explains that the program should work on any OS, but he has so far only been able to test it on MacOS.
This week on the popular YouTube show Hak5, SDRSharp plugins are discussed once more amongst other topics. This time at around the 17 minute mark, Shannon discusses how to install plugins that do not have automated installers. For an example she shows how to install the Level Meter plugin.
Over on YouTube user John Miller has uploaded a video showing an example of DSD+ decoding an NXDN96 voice signal. NXDN is a digital voice protocol by developed by Kenwood that is often used by public safety organizations.
John uses SDR# to receive the NXDN signal and then pipes the audio to DSD+ using Virtual Audio Cable for decoding.
Kyle Keen, the primary author of the well known and highly used rtl_fm, rtl_power, rtl_adsb and recently released rtl_sdl tools has started an indiegogo fundraiser to help raise funds to pay salary for ideally at least one month of dedicated RTL-SDR software coding. Kyle is hoping for $3,000 USD per month of coding. The time he codes for will scale proportionally to the amount of funds raised.
There are several levels to contribute at but the ideal contribution is the ‘Voter’ level at $50 USD. By contributing to the fundraiser at the ‘Voter’ level you will be able to have a vote on what features are to prioritized. It is also possible to contribute at a lower level of $10 USD and forego the voting perk.
The list of features to be implemented and the voting system can be found at igg.kmkeen.com. Important improvements will be made to the librtlsdr library, rtl_sdl, rtl_adsb, rtl_tcp, rtl_power and rtl_fm..
We hope that if you have enjoyed the RTL-SDR in some form you will contribute to this developer and help make this hobby an overall better experience.
