Since 2021 we've posted about Viol Tailor's "uSDR" (microSDR) software a couple of times. uSDR is a lightweight general purpose multimode program for Windows that supports the RTL-SDR, Airspy, BladeRF, HackRF and LimeSDR radios. The software can be downloaded from SourceForce.
Viol notes that recently the project has been updated to V1.5.0 which brings the following new features and changes.
lock device frequency on zoom option
keep waterfall history – the very great option, do not lose any rare signals
advanced passband IQ recorder
passband IQ TCP server for remote processing, C/C++ client source examples included
advanced audio player, auto selectable sample rate, separate left/right channels
markers import option convenient for merge markers
Thank you to Don for submitting news about the release of his new software titled "Skies-ADSB". Skies-ADSB is a browser based app that provides a 3D view of the air traffic around your area. The software can be served on a local networked Raspberry Pi, with ADS-B data being provided by an RTL-SDR connected to the Pi.
skies-adsb is a virtual plane spotting progressive web app (PWA) / virtual aquarium (with aircraft instead of fish) / interactive real-time simulation.
Aircraft are tracked via unfiltered ADS-B transponder data in real-time and rendered in 3D.
Thank you to Joseph IT9YBG for submitting his article describing how he has made an RTL-SDR based panadapter for his TECSUN PL660 portable shortwave radio. The post is a series of pictures that show how Joseph was able to open the PL660 and connect a coax cable to the IF output, and mount the connector on the plastic cover for easy access. He then connects that IF output to the RTL-SDR via a 10pF capacitor.
The result is that Joseph is able to receive the IF output of the PL660 at 451 kHz in SDRUno with his RTL-SDR Blog V3 running in Q-Branch direct sampling mode. He notes that although the IF bandwidth from the PL660 is small, it is possible to decode digital signals by passing the audio demodulated by SDRUno into decoding software.
On this weeks episode over on the Frugal Radio YouTube channel, Rob investigates if the YouLoop antenna works well at VHF and UHF frequencies. The YouLoop is a popular portable passive loop receiving antenna that can be used with sensitive radios like the Airspy HF+ Discovery. It is mostly used for HF reception, but advertised to work up to the VHF band as well.
In his video Rob describes how the YouLoop can receive on VHF frequencies by acting as a folded dipole. To test this capability he connects an indoor YouLoop to an RTL-SDR Blog V3 unit, and confirms that he is able to strongly receive VHF airband ATIS, airband communications and various VHF digital and analogue voice signals.
Rob then goes on to check if the YouLoop works in the UHF bands, which it is not advertised as being capable of receiving. However, Rob does find that the YouLoop worked well on relatively strong UHF signals up to around 800 MHz.
Does the Airspy Youloop work on VHF? What about UHF and 700/800 MHz?
Over on Twitter @dereksgc has been monitoring the 'Meridian' communications satellites, which are Russian owned and used for civilian and military purposes. The satellites are simple unsecure repeaters, meaning that actually anyone with the hardware can transmit to them, and have their signal automatically rebroadcast over a wide area. This has been taken advantage of recently by anti-Russian invasion war activists who have been trolling the satellite with SSTV images of the Ukrainian flag, as well as audio.
Apart from intentional abuse, a side effect of being an open repeater is that sometimes the satellite can pick up powerful terrestrial signals unintentionally, such as analogue broadcast TV from Turkmenistan. Over on his blog, @dereksgc has written up an excellent post documenting the background behind this finding, his entire setup involving the hardware he's using and how he's aligning with the satellite, and what software he is using to decode the TV signal. In his hardware setup he notes that he uses a HackRF, but that a RTL-SDR would suffice.
TPMS is a system installed on many modern cars (or retrofitted on older cars) that wirelessly monitors the tire pressure on vehicles in order to provide dashboard information that can improve safety and fuel economy. TPMS system typically transmit on license free bands, such as 315 MHz which can easily be received with an RTL-SDR.
Ross owns a 2008 Toyota Tacoma which has a built in TPMS system. Unfortunately he found that one of his sensors was broken as the TPMS warning light was consistently on, despite knowing that his tire pressure was correct.
Instead of purchasing an expensive TPMS diagnostic tool, Ross broke out his RTL-SDR and fired up rtl_433 which already contains a ready to use TPMS decoder. From the data received, Ross was able to determine that only three sensors were transmitting. Ross then goes on to use the RSSI signal power strength measurements provided by the rtl_433 output, while moving the antenna next to each wheel to determine exactly which wheel had the faulty sensor.
Ross's post goes into further details about his setup and the data he received from the sensors. He also created a follow up post, describing a bash script he wrote to automate the process.
In our last post we mentioned that a 'pre-release' public version of SDR++ for Android was recently released. Now over on the SignalsEverywhere YouTube channel Sarah has uploaded a new video where she reviews and demonstrates the new SDR++ Android App.
In the video Sarah demonstrates how to connect and start a SDR, shows SDR++ in action, then tests listening to NOAA weather audio reports, Inmarsat reception via the bias tee support, P25 and broadcast FM. She also shows how it's possible to use the split screen multitasking feature on Android to send audio from SDR++ into APRSdroid for APRS decoding.
She goes on to show how to fine tune the screen PPI resolution for different sized devices, and how to set up multi-VFO listening on the HF bands. Next, she compares the audio decoding quality between SDR++, SDRTouch and RFAnalyzer. Finally she shows that a HackRF running at a wideband 20 MHz of bandwidth can run smoothly.
The Android SDR App That Beats Them All! Supports RTL-SDR Airspy HackRF and Many More!
SDR++ is an open source program compatible with most software defined radios including the RTL-SDR that has been going through rapid development making it now one of the top software choices.
Yesterday a public 'pre-release' Android version of SDR++ was made available for download. The release is announced as a 'pre-release' due to various bugs still existing. However, we note that we have been testing a private release for the past few weeks, and we can say that it is working great most of the time. The Android App replicates most of the desktop experience perfectly, and it operates very smoothly on most modern devices.
The author Alexandre Rouma writes:
I'm happy to release the first public pre-release of SDR++ for android. It's still quite early and has a few bugs and quirks that you might run into:
SDR MUST be plugged in before starting SDR++ and you MUST press refresh in the SDR source you're using before pressing play if you first plugged in the SDR or unplugged/replugged, otherwise expect a crash. The USB handling still needs some work.
There are still a few UI glitches
There is no easy way to select a path for recording or file for playback
The audio sink on Android may have higher latency
All menus sometimes close when app goes in the background.
Resizing the menu and/or waterfall is kinda fiddly, be precise when trying to grab the resize bar!!!
At some size menu sizes, the app crashes. If this happens, start in landscape
On Samsung devices, the keyboard doesn't always work for some obscure reason...
Since phones usually have a high screen resolution, set the DPI scaling in the Display menu or you'll have a hard time using the app.
Current Device/Protocol Support:
PlutoSDR (network only)
In any case, I'd love to get some feedback on it, so feel free to try it out and let me know!