If you want to have something similar for use at home, you could take a look at http://kiwisdr.com.

I have one, but you need to hunt down EMI sources, before you can properly use it.

You can also use high-Q antennae, if you have a frequency of interest. For instance, on HF (shortwave) a tunable small loop antenna does a whole lot better than a wire antenna in a high-random noise environment. You may still end up chasing down various bogies, but a lot of them can be blocked with the directionality of the antenna or the filtering properties of the antenna (higher Q antennas are more narrowband).

> but you need to hunt down EMI sources, before you can properly use it.

Do you have any recommendations for doing this? I have some source that interferes every 11 seconds for a second or so. It causes packet loss with my wifi (2.5 and 5GHz), and makes my bluetooth game controllers really frustrating to use, since input are missed every time it does it. I assume it's in the microwave range.

I'm familiar with RF test equipment, and I've thought about renting a spectrum analyzer, but I assume there's maybe some cheaper way.

You could get an rtlsdr dongle cheap and use it as a spectrum analyzer. There are command line utilities for that task in with the drivers online.

they don't go up to the 2.4/5Ghz range though, they max out at about 1.7

Yeah, but it seems he's got a broadband noise source, likely the 2.4 Ghz is a harmonic of something that is within their range.

The limited availability of KiwiSDR's have made it crazy high priced. I've been trying to get one for a year now but they're up to like $600 on aliexpress. KiwiSDR2 has been announced, but that's a ways off from being sold.

WebSDR on other hardware is a better alternative-ish.

It is closed. There is a lot of ham radio software that isn't open source. And a lot of open source isn't developed openly. You would think that all of it would be open source but I think a lot of hams didn't come from software world.

There’s quite a bit of overlap, actually. For some reason all of the old hams want to do .NET applications, though.

I really think this is one of the reasons for the stagnation in the field.

What would people want this to look like? Is there a backlog anywhere of stuff people would want?

Edit: I was thinking maybe something that reads from an rtl or airspy, or maybe soapy? Then takes requests for channels over websockets from a wasm front end, then have the demod wasm side? And a waterfall streamed as a video to aid in making the channel selection? It would save bw to put demod server side, but this way clients could use custom demods if they want.

The perceived stagnation in the field is because you can’t multiplex an SDR stream. One user can control the radio at a time. You can not listen on more bands than your radio can receive at once. Capping out at 192hz band audio sampling on most hardware. Which means you can read a wide signal but you can only read one area of the spectrum at a time.

You would need more radios. If you added more radios you would need antenna that worked across the various bands people would want to listen in on. Those can create “cross-talk” to other antenna close-by. There’s not a simple solution to this. Nor does the novelty of it warrant solving this problem.

I think something like FlightAware where users sample their own radios at frequencies and submit them to a service that can aggregate the spectrum in real-time is the only real way to provide a web-based “tune to any radio frequency” SDR.

An airspy can digitize 12MHz of bandwidth at once. Even without a gpu you can spit out easily over a dozen digitally subtuned channels. The bandwidth for all that raw signal data going out would be the problem. Only one person can control where that 12MHz is centred, but people can pick where in it they want to listen just like they do with websdr now.

Even a $30 RTL-SDR dongle can record 2Mhz of bandwidth reliably. I've recorded hours of signals just in case it sometime later becomes interesting, and it all lives in a little corner of my hard drive.

Damn! Yes, you would need to have one user center the spectrum read and you can mux the output to users wanting specific bands but I had no idea an airspy had such a wide audio capture.

Edit: I looked it up. You are indeed correct. 10MSPS IQ output. 10Mhz panorama spectrum view. That’s ridiculous! I just bought one.

I think the boxy one, the r2 not the mini, had some hacky way to get 80msps but it didn't specify how that made it over usb or why that wasn't the normal operational mode.

To add color to this. The reason being is because a lot of the old C++ libraries and code no longer function so pushing for .NET applications helps bring them into the 21st century. Also, I think it’s more because of the fact that C# is very familiar to C/C++ developers. However, I believe the true target architecture should be Linux and there’s some work in this area. GNU Radio, Gqrx, Qradiolink.

It just depends on where you are looking. There’s plenty of OSS for SDR (it’s in the kernel, btw) on Linux. Windows you’re going to get closed source 80% of the time. Mac, forget about it.

-Old Ham

Take a look at gnuradio.

for open source alternative take a look at https://www.openwebrx.de/

Can also demodulate digital modes (DMR, YSF, etC) and it have nice, modern UI.

WebSDR have a weird list of requirements if you want to get install file - should open instance to public, provide lots of info, etc etc etc. It's not just closed-source.

I thought that it couldn't demodulate DMR and other modes unless it had the hardware to do so. Feel free to correct me if I'm wrong, though.

DMR can definitely be handled by software.

I have done this with a crude rtl-sdr stick.

You definitely can, but legality of such procedure is questionable. DMR uses AMBE codec, which require licensing from DVSI, but you can find open-source implementation on github (mdelib, jMBE). Projects such as DSD-FME[1], which allows you to decode much more than just DMR (P25, NXDN or SDRTrunk[2], which allows you to listen to trunking systems (p25, dmr tier 3 and much more) uses software implementation. OpenWebRX users software decoder too https://github.com/jketterl/digiham

[1] https://github.com/lwvmobile/dsd-fme

[2] https://github.com/DSheirer/sdrtrunk

I use https://github.com/jketterl/openwebrx with RTL-SDR sticks

Try the fork at https://github.com/luarvique/openwebrx/