Well, sort of anyway.
I'm going to write up a somewhat long paper on my SDR experiences, including getting the OpenWebRX+ software to work.
But in the meantime...
I was working with 4 SDR's, the RTL-SDR V3 & V4, the SDRPlay and the HackRF One. I managed to get all working in some form. There were lots of problems, mainly with documentation, and driver compatibility.
I've discussed previously that the Windows Version of OpenWebRX+ is a hack, running with WSL and Docker. I wanted to test out these SDR's in their native Linux as well, and installing Ubuntu was the easiest part of the entire process.
Some quick conclusions. The RTL-SDR V4 is by far the easiest to install, and it sounds great with WFM. AM not so great, as it appears that there is some form of AGC going on during quiet moments, and it can't be turned off. I had thought it was hardware, but it turned out to be a 'feature' of OpenWebRX+ (see below). Downsides include bandwidth limitations of around 2Mhz, and easy overloading of the radio on strong signals.
The RTS-SDR V3 is about the same as the V4, but can't really receive AM properly.
The SDRPlay was absolutely horrible to install and get working correctly, due to the proprietary nature of its drivers. It was extremely difficult to match up what the hardware manufacturer released as a driver (they call it an API) and the OpenWebRX+ interface. I ended up having to recompile and build parts of that OpenWebRX+ interface from source, so that it matched up with the installed version of Ubuntu and the API.
I never got the Windows Docker version running with the SDRPlay, but FM worked nicely with Ubuntu. AM was better than the RTL-SDR, but that AGC issue was still there. It wasn't there with the proprietary SDR software provided by the manufacturer (in lieu of OpenWebRX+), so that's how I know that the issue is in the OpenWebRX+ software.
The front end of this receiver was resistant to strong signals, and I was able to get up to 10Mhz bandwidth on FM, albeit at a cost to CPU usage. Better values were 4-6Mhz, but even that put a strain on the server.
Beware of the HackRF One. It can't get enough power from a USB port, and you need to run it plugged into a powered USB hub to get it to work. That took some time to figure out.
When running, it suffered from a great deal of noise in the signal that I couldn't get out, even on FM. It sounded like crackling, and I believe it's due to inadequate shielding. AM sounded even worse than the RTL-SDR V4.
The big advantage of the HackRF One is its bandwidth, up to 10Mhz (like the SDRPlay). Software-wise, it was easy to install (other than the power issue).
So to conclude. None of these will receive the AM broadcast band in a satisfactory manner with OpenWebRX+. The only way to achieve that is to go into the source code and effectively duplicate what the SDRPlay folks did with their software, SDRuno. That is definitely a project for another day (or week, or month).
Ironically, the RTL-SDR V4, the first SDR I tried out, may be the one I go back to. It puts the least strain on the server, and, at least according to other users, can support many more users than the SDRPlay. Plus it has the advantage of working on both Ubuntu and Windows, whereas the SDRPlay only worked on Ubuntu.
But we'll see. I need to run some more tests over a period of time before I make my final decision.
AM reception will have to wait for a little longer. As will the user interface changes I want. I've had enough frustration to last me a while, but will eventually get back to the project. I just want to complete the testing as is and get the thing up and running over the Internet.
I don't understand most of it but admire your undying commitment to making it work.
@richpowers Similarly, ditto.
Perhaps this is a good time to say I appreciate everyone on Part15.org being a bright a enthusiastic crowd! Really do. I get about half of what @artisan-radio is saying, the other half I'd have to read more carefully or look up.
I like being here and absorbing more than I can possibly make use of. It's a good hobby. If some of the details get beyond being immediately useful and a bit esoteric, I go knowing y'all don't mind if I skip it. However, know that I do bookmark some things because you just don't know what will be useful in the future.
Yeah, I know I hijacked the thread a bit, but thanks for putting up with me.
I've got the SDR up and running over the Internet for testing purposes. I'm using the SDRPlay RSP1a, and displaying about 4 1/2 Mhz of bandwidth of the FM band (around my station). There's actually 6Mhz in total, but display and sensitivity issues got me to where it is (about 1.5 Mhz above the band is there, but hidden by the status box on the right).
You can access the SDR directly with http://artisanradio.hopto.org:18073 or go the website at http://artisanradio.com and follow the link to the SDR at the bottom of the page. I need to update that page, as the streaming link is defunct, and most of the info, particularly the schedule, is out of date. Later.
Let me know how it works. The SDR server gets internet connectivity to the outside world through a VPN, and I'm always concerned how it will perform. It's pretty good here. I'm also a bit concerned about the server CPU utilization (it's an old piece of hardware).
The SDR needs a fairly mainstream browser to work and display properly (Chrome, Firefox, etc.).
@artisan-radio I just listened and it looks like you are on 106.9 FM?
Wasn't sounding right....overmodulating? Liked what I heard though!
Is that the Talking Sign you are running and somehow converting the audio to FM 106.9?
That could also, if that is the case, be the bad audio that the Talking Signs have as we know.
I went to the Artisanradio.com link as the other link was taking too long to load.
Don't think I'm overmodulating, but it could be a bit of audio stuttering due to a variety of reasons. Maybe you could try again at a different time tomorrow.
Thanks to all for giving it a try. I'll leave it up for a while.
I should explain a bit more. I'm using a Decade transmitter on 106.9, tuned down to minimum power (a lot less than Part 15, never mind BETS). The signal can't be discerned at all at street level directly below my apartment (about 80 feet or so) - you just hear static and not a trace. I found that RSS-210 and BETS transmitters used 'as is' tended to overload the front end of the SDR, as the receiving antenna is pretty close to the transmitting antenna. You'll notice that, while Artisan Radio appears quite strong, it's not, in fact, much stronger than other FM signals on the band. And that's with a distance of about 2 meters between the antennas. You can even get the RDS data from a lot of the other stations that appear on the signal waterfall.
As I mentioned previously, AM signal reception is not acceptable, and I've removed the profile for the time being. While the SDRPlay sounds quite good under OpenWebRX+ with a loud AM signal, during quiet moments the noise level rises dramatically to uncomfortable levels. This is behavior from the software, as SDRuno, provided by the SDRPlay manufacturer, doesn't exhibit this behavior. In fact, AM reception is almost comparable to FM with SDRuno, albeit with a bit less dynamic range.
It has to be remembered that OpenWebRX+ was designed primarily for amateur radio and shortwave applications, where signals fade in and out, and fidelity is of secondary importance to actually hearing those signals. It's almost like there's a built-in Automatic Gain Control for AM (and likely for other modes such as SSB). I will need to go into the software and attempt to turn that off, if possible.
@artisan-radio It seemed to me at my end that you had too narrow a band width at 106.9 and some of the audio was clipping. It didn't have enough room. I went to it again. The space from 106.9 to 106.7 the next broadcast frequency down was 10 lines(100klz tuning) and if I moved the dial tuner it went to half a line over and was at 106.85 half off the station already(distorted) so it seemed that you don't have near enough the 150 kLz bandwidth for the audio. That seems to be what I was getting from what I saw at my end. With that fine a tuning adjustment I should have been able to go to 106.8 before I would notice it "off the station" or in other words detuned. So what I was hearing was even right on 106.9 the audio was clipping a bit.
I'll check the configuration file for the software and see what the filter setup is for Wideband FM.
It turns out, at least from my research, that the IF bandwidth for WFM (broadcast wide FM) is fixed in the software, and can't be changed. The software itself would have to be modified, and I'll add that to investigate when I do get around to going in and changing things a bit.
I don't mind the way things sound right now.
@artisan-radio Went again today and listened for a bit. Seemed better today but some songs had the distortion. Depends on the song. A very narrow audio bandwidth as 50 klz off(was wrong before when I said .5 klz off) and off the station already but shows + or - 75 klz which is right for FM audio bandwidth.
The speech in between songs is clean but that is a computer voice with little dynamics. I like that it can't pronounce Shelley Fabares' last name!
I love the music format though. We think alike there. I'll tune in from time to time.
@mark If you tune in to some of the other stations being displayed, do you hear the same distortion? Probably the least objectionable is CBC at 105.7. At least they play classical and other genres rather than modern crap.
@artisan-radio I moved the dial from one end to the other in the part of the band displayed
and got 4 stations and another weak one down around 103.5? right at the left end of the displayed coverage. The strong ones I got were 104.3, 105.7, 106.3, 107.7 in addition to yours at 106.9. They are all the same as yours. Not clean sounding and it varies on the song being played. But speech is clean. Also the same moving just 50klz(inbetween one line) off center and already off the station partially on the others too. In fact a couple of those others are worse. I am of course listening through the laptop speakers, which of course is not full range audio at all but I hear perfectly if audio is clean or not. I don't have right now an external speaker to listen to from the laptop. Right now Shy Girl by Johnny and the Expressions is playing followed by Jay and the Americans Since I Don't Have You and these two songs are clean with no distortion. There's also some other settings I have but didn't try any of them.
On another note if this segment of the band represents the actual FM band where you are located there seems to be several spots to go with an over the air station, just in the part of the band from 103.5 to 107.5
If you can hear it with other stations, then, as I thought, it's something in the software. As I stated previously, the main reason that the software was developed was for amateur radio and shortwave listening. Wideband FM was added at a much later date, and there may be problems with it.
The waterfall display on the SDR doesn't tell the entire story of the spectrum. It's what's received in my studio, surrounded by concrete.
Outside, and in the car, there is plenty of noise, as well as other weak stations, that you don't see. Right now, you're seeing (and hearing, if you tune in), the strongest.
There is no 'best' frequency right now on the FM band. I chose 106.9, as it's relatively clear, there are no local stations, and the Artisan Radio signal is so weak it barely clears my residence. So no interference.
AM is much better, but the concrete jungle impairs signals. And the SDR's don't work properly, at least for reasonable listening, on the AM band.
I'll have to look at the WFM and AM reception modes in the software, but I'm taking a bit of break from it right now. I'm primarily focused on programming and my schedule, and that takes time.