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!
On this weeks SignalsEverywhere episode, Sarah demonstrates and shows us how to use the SDR++ Server, which was released as a beta earlier this year. SDR++ Server is similar to software like rtl_tcp, and Spyserver as it allows us to connect to a remote networked SDR like an RTL-SDR. Compared to rtl_tcp and Spyserver however, SDR++ Server has a huge advantage in that it is compatible with almost any SDR, and enables the full range of control options for RTL-SDRs.
In the video Sarah shows us how to activate the SDR++ server module and how to connect to a remote RTL-SDR running the SDR++ server on a Raspberry Pi. She goes on to show how to connect to other SDRs running on the Raspberry Pi as well, such as the SDRplay RSP Duo, LimeSDR, Airspy R2 and Airspy HF+ Discovery. Finally she goes on to show how to set up the server on Windows and a Raspberry Pi.
SDR++ Server | Remote RTL-SDR SDRPlay LimeSDR AirSpy and More! | Raspberry Pi and Windows Setup Tut
Thank you to Nobu who has submitted news about the release of his new product, a machined aluminum enclosure for the Airspy HF+ Discovery. The Airspy HF+ Discovery comes by default in a plastic enclosure. Although the HF+ Discovery does not need a metal enclosure to perform well in terms of PCB noise rejection, a metal enclosure gives the product a much more premium feel, and aesthetically looks great. Nobu also mentions that the metal enclosure may help with heat dissipation.
The product is only available on Amazon Japan and may show no stock for international customers. If you are outside of Japan, to be able to purchase you may need to use a Japanese market buying agency, many of which can be found online.
@lambdaprog, creator of Airspy products mentions that this enclosure may help with Airspy HF+ Discovery devices running 24/7.
The RF shielding is already achieved using a small anechoic chamber made from the PCB itself, the metal can, and some EMI absorbing material. So, I won't expect much changes in that aspect. However, this alu case can help with the heat dissipation in systems running 24/7/365.
SDR++ is a general purpose receiver program compatible with almost any software defined radio including the RTL-SDR. Recent developments have seen the author release a beta of "SDR++ server" which is a program that allows users to access SDRs remotely, by connecting to them over a network connection. This is similar to existing server applications like rtl_tcp and Spyserver, however like SDR++ itself, SDR++ Server is compatible with almost any SDR and that is a major drawcard.
Today I'm happy to release the beta version of SDR++ Server! It works with all devices SDR++ supports. Since it's beta it's still missing compression and VFO+FFT mode.
As a demo, here is a LimeSDR being streamed over WiFi at 16MS/s
Get it here: https://t.co/DqvgHMZmm9#SDR#SDRPPpic.twitter.com/116JftzEOy
The server is still in development and the author notes that he is still working on adding new features like lossless compression techniques in order to reduce network bandwidth requirements. However, it has already seen to be running well in tests with a remote server positioned half way around the world, even without compression enabled.
Started working on adding lossless compression to SDR++ server. How well it works depends on what signals you're looking at and what SDR you're using. What I'm seeing with general purpose compression tables is 1.1 to 2.5 times compression (usually 1.5+). Custom tables should help pic.twitter.com/a1WRvxmdDs
The KK5JY Loop on Ground (LoG) antenna is a 15 feet per side square loop designed for reception of HF and lower. It simply consists of an isolation transformer and wire that as the name implies is placed somewhere on the ground in a square loop like shape. It is cheap and easy to build and compact in that it does not take up any usable space.
In his latest video Rob from the Frugal Radio YouTube channel tests out this antenna with his Airspy HF+ Discovery SDR. He uses a bit of wire lying around, and a low cost 9:1 Balun from NooElec as the isolation transformer. With this antenna he was able to pick up signals in the USA and all the way over to Australia from his home in Canada. NDB signals were also receivable.
2022 LoG (Loop on Ground antenna) for SDR radio tested on Airspy HF+ Discovery SDR KK5JY HAM radio
Job Genheniau's projects have been featured several times on this blog in the past for imaging the Milkyway and other astronomical objects like supernova's and protostar regions with a 1.8m radiotelescope dish and RTL-SDR or similar SDR.
In his latest achievement Job has noted that he has had some limited success in observing NML Cygni with his dish and an Airspy Mini SDR. NML Cygni is a 'red hypergiant' star situated within the Cygnus constellation, and it is one of the largest stars by radius known. Prior observations have found that it exhibits a spectral line at 1612.231 MHz.
Job's setup consists of his 1.5m dish (extended to 1.8m with mesh) on a rotor, a custom feed tuned for 1612 MHz, a 0.47dB NF low noise amplifier, an RF filter and an Airspy Mini SDR. Observations were made in SDR# and plotted with Excel.
The NML Cygni hypergiant is difficult for amateur's to observe, and Job notes that he is not aware of anyone previously observing it with a 1.8m dish. He notes that he had 20 failed attempts, but 5 recordings that stood out as possible successes.
However, ultimately Job has been unable to claim that the star was successfully observed, but his results to appear to show some possible success. He notes that some of the uncertainty stems from the fact that on some recordings he observed the peak at the expected -25 km's blueshift expected from the star, however other recordings had the peak at the wrong blueshift.
In one of his latest videos, Rob from the Frugal Radio YouTube channel gives us an interesting alternative way to enjoy a theatre show by demonstrating what he heard on his Airspy SDR when taking it to a Christmas theatre show. In a modern theatre show the actors and actresses typically wear hidden wireless microphones and earpieces, allowing their voices to be amplified and instructions from the producers and directors to be heard. If close enough, these devices can easily be picked up with a SDR and antenna.
In his video Rob explains what sort of radio devices and frequencies are used at the theatre, and despite a few set backs he manages to listen in on these devices from the lobby and from just outside the theatre complex.
Some of the things he hears includes backstage instructions from the directors and production team and of course audio from the performers, including backstage conversations.
2021 SDR Guide Ep 12 : SDR Theatre fail with my AirSpy R2 and RTL-SDR dipole kit