A Pi and RSP1a ....run via WebGUI ?

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vk7jj
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Re: A Pi and RSP1a ....run via WebGUI ?

Postby vk7jj » Mon Apr 09, 2018 6:32 am

How does the ‘second Pi inside the house’ setup work ?


Not as easily as a Pi in the shack and VLC in the house because VLC is already built :-)

The Pi in the shack runs software called node.js which (when you code it to do so) creates a web server interface.

That interface is designed to control the Pi in real time using a technology called web-sockets, they send non-audio data back and forth between the Pi and the web page so that my S meter code and nice large "LED" web display code etc updates the web page in real time at the same time as I command my radios, usually an FT-991 Yaesu but sometimes an FT-857D, to scan at the rate about 50ms per channel and control all their other functions via CAT.

The radio control is done at via 38400 baud direct USB connection to the FT-991 or via a standard serial interface to SDRUno running on another machine. SDRUno also has CAT control using a subset of the Kenwood CAT command set.

The audio of the radio or SDRUno or whatever is connected to the Pi via a USB-to-audio dongle and is sent by the Pi using a code library called FFMPeg which has to be compiled on the Pi along with CODECs of choice like Opus which offers excellent high speed compression for voice, or simply using PCM which is just sliced audio blocks.

The technology to play live audio in real time in a web browser is effectively non existent, unless you code it yourself or use a Javascript library. It's my personal holy-grail to get real time web-browser audio going properly. But the audio stream in PCM or MP3 using an RTP stream can be read by VLC and by a small test app from FFMPeg called FFPlay on a Mac if you pass it the right information in an .sdp file. FFPlay can only be invoked via a terminal program or a bash command, but that can be setup to run nicely on a Mac using their new inbuilt version of Javascript scripting

If I choose to use a web browser to play the sound in, then I have to program the Pi to stream in AAC format. That involves the Pi breaking the audio stream into chunks and storing those chunks in (say) ten x 1 second files on disk, along with a .m3u header file which describes their contents/size. That means a 10 second delay which is the shortest I can get AAC working. The Pi/node web server then serves those little files in such succession that they are integrated in the browser back into an audible audio stream.

All of the programming of all the above has to be done personally by hand.

The only reason I've gone into detail is to give an indication of what is required so at least you know whether you might contemplate it or not.

The other system mentioned by SDRPlay Support called openwebrx is truly amazing from my perspective, a single programmer solved a whole bunch of those problems, streams his own designed compressed audio and waterfall information, drawing the waterfall a line at a time using SVG graphics (from memory).

I only wish his project would be taken up and supported sufficiently to take it to the next level, it does exactly what people on this board seem to be crying out for, as I am. Coding is so specialised, I cannot do it. I started in assembler and then Forth, did a bit of C++ when it was first invented and then got stuck in industry doing web-internet front end, middleware and server and have next to no experience in the necessary areas, whereas large parts of the SDRPlay development are directly relevant, so they could do it :-)

Perhaps if enough of us asked nicely?

Regards, Phil

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sdrplay
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Re: A Pi and RSP1a ....run via WebGUI ?

Postby sdrplay » Mon Apr 09, 2018 7:52 am

OpenWebRX support SoapySDR. We fully support SoapySDR, so should work fine with RSPs.

Have you tried it?

Best regards,

SDRplay Support

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NeilP
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Re: A Pi and RSP1a ....run via WebGUI ?

Postby NeilP » Mon Apr 09, 2018 8:15 am

sdrplay wrote:OpenWebRX support SoapySDR. We fully support SoapySDR, so should work fine with RSPs.

Have you tried it?


SDRplay Support


Hi

Well , yes i tried the test interface for the OpenWebRX page in Australia that you posted earlier, but at the moment , no hardware as yet to test myself and play with options.

But I can't really afford to go spending time and probably a few hundred pounds to find out I cannot get it to work (simply) as I wold hope.






Phil, that you for the information of how you use the second Pi. I see you are using full on Amateur radios to control, my only radio is an old Yaeseu FT290 from the days I did operate 2m band, so not good for this.


I was actually under the impression that this forum was aimed at the use of the SDR Play RSP devices.




I was considering a much cheaper setup of an RSP1a and a raspberry Pi, probably the latest 3 B+ one since they are relatively cheap part of the setup.


Maybe for my requirements you know of a different hardware solution to this, that gives me remote listening via a WebInterface..

Maybe some old Yaeseu hardware that I could pick up cheap at a Ham fair or online ?


Requirements again are :

Pre program a selection of local Aviation frequencies and marine channels and have them scanned. Not looking to search for new stations or have a pictorial bandwidth spectrum

Scan these programmed frequencies and stop on activity.

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vk7jj
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Re: A Pi and RSP1a ....run via WebGUI ?

Postby vk7jj » Mon Apr 09, 2018 9:11 am

Neil,
Lots of amateurs have lots of stuff, I hardly have much and being both poorish and old lots of mine is poorish and old :-(

The SDRPlay hardware and software is absolutely marvellous and their support is second to none, I have an RSP2 and an RSP1A. I bought the 1A when my RSP2 died, then SDRPlay replaced the RSP2 under warranty when I certainly didn't expect them to.

Everyone's got opinions, but nobody's got the answers.

Pi's are great and I love them but if you want to make the most of an RSP purchase then a Pi as your primary device is not the way to go.

Here are your software choices, they are very obviously slanted to Windows.

https://www.sdrplay.com/downloads/

• SDRUno is excellent software and SDR-Console is also excellent - they are both Windows only.
• HDSRD is fine, it uses fewer resources than the others but again is Windows only.
• CubicSDR is very good and runs nicely on a modern Mac, Windows, and also on Linux but many reports indicate not at all well on a Pi simply because of the lack of grunt.

You're chasing a web interface, as per the above conversation the only solution that supports an SDRPlay device that I'm aware of is OpenWebRX.

Looking at your scanning / listening requirements, that's exactly what I wanted to achieve in all my Pi playing around! Unfortunately what I described is a roll-one's-own solution I was able to get together based on work experience.

I still think SDRPlay should grab hold of OpenWebRX before someone else does (other than the Beaglebone Black people) and run with it with a Pi image at least, it would do what you want for general listening without scanning, on a Pi.

While on my SoapyBox you'd have to think that SDRUno is getting too complex to develop sustainably much further. Trying to build a universal software tool that meets everyone's demands is impossible, it's like wanting a single tool that can hammer and saw and drill all at once.

So in the end they will be forced to embrace change and the best change imho is offering a mechanism where they supply a software kernel that can be accessed by educated *home* programmers and tinkerers, to try to create a cottage industry, where people can produce custom solutions including web based solutions to meet almost any personal need.

I guess I've said too much!

Cheers, Phil

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NeilP
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Re: A Pi and RSP1a ....run via WebGUI ?

Postby NeilP » Mon Apr 09, 2018 9:30 am

Think I am going to have to just stick with the handheld Uniden Bearcat Scanner. :(
Was hoping to move to a modern solution, but it does rather look like there is not one as yet.

Used to live in the in large family farm house, with a separate radio shack in the attic,, dark room, plus sheds too.

Now I have moved to an apartment, do not need yet another PC running.

Already have two int eh attic , one as backup server and another as 24/7 music streamer box. No way am i going to run another box up there to run an SDR and just no room in the one bed apartment for more kit indoors.

The whole idea was to get rid of the Bearcat Scanner off of the bedside table to reduce clutter and do the listening off the iPad or iPhone.

This will not work out .

SDR is too complex for and not developed enough yet to warrant. Rather like when I jumped in to X-10 home control stuff..now my flat is setup with that, nothign will interface with it in the modern world without having another 'translation server running to allow the X-10 devices to be run from modern digital age home control interfaces.


Time to drop the subject and realise that until the whole concept becomes more mature and developed , it is not for me.

Thanks for your help

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NeilP
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Re: A Pi and RSP1a ....run via WebGUI ?

Postby NeilP » Mon Apr 09, 2018 9:33 am

This is what I want:


http://www.winradio.com/home/rlx-810.htm



but not for the £4000 plus price tag.

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vk7jj
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Re: A Pi and RSP1a ....run via WebGUI ?

Postby vk7jj » Mon Apr 09, 2018 9:45 am

Or one of these

http://www.flexradio.com/amateur-produc ... flex-6700/

They have *stunning* apps for iOS devices. So I'm told anyway ;-)

Edit:

http://www.flexradio.com/amateur-produc ... r-for-ios/

p.

PS. Good to chat, thanks for the opportunity and it's fun hearing your situation - let's hope SDRPLay Support or someone else can turn the thread around, wave the proverbial wand, and produce a Happy-er Ending!

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NeilP
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Re: A Pi and RSP1a ....run via WebGUI ?

Postby NeilP » Thu Apr 12, 2018 6:18 am

These guys have a working mobile Safari iOS enabled SDR that does near enough what I want.
Stores frequencies, but no scanning of saved channels.

websdr.ewi.utwente.nl:8901/m.html

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vk7jj
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Re: A Pi and RSP1a ....run via WebGUI ?

Postby vk7jj » Thu Apr 12, 2018 7:03 am

websdr.ewi.utwente.nl:8901/m.html


Good to see, good to see collaboration with the audio guy from openwebrx too, it would be a shame if his work wasn't taken up more as its just about one of a kind.

Not sure if that system would suit you though being (I think) HF only with a ~29MHz ceiling?

The question about scanning I've had in the back of my mind is how much of a limitation typical SDR hardware has in terms of the ability to quickly change frequency over a wide range. Multiple PPL's over a wide frequency range almost dictates long settling times, not so sure about the main oscillator but being designed to sync with external sources probably also means that the design of the whole SDR is geared towards stability and lack of jitter at the sacrifice of fast switching times. Quite the right thing to do, given the current predominant use of waterfalls and viewing band segments.

Pushing my RSP2 to the limit at it's highest CAT speed running SDRUno from my Pi web interface showed it was on the steady side and at one stage it seemed to lose it's mind briefly and returned erroneous CAT codes, though I've not tried to duplicate it. Love to know what the RSP hardware can actually do in that regard.

Phil

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NeilP
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Re: A Pi and RSP1a ....run via WebGUI ?

Postby NeilP » Thu Apr 12, 2018 7:36 am

Yes, that particular link was frequency limited, but at least it does show that the ability to all it to work on am iOS device is there.

The channel scanning speed would not be a great issue, the bands I was considering were all within a (relatively ) close spacing 118-160Mhz. and scan speed as long as it did 10-12 channels every few seconds that would be enough.

Am going to tinker with the Skywave distro this morning and see if I can get this random USB Geniatech tuner to work with the Mac

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