Best setup for RDS?

[g33ky]

Whats in your opinion the best setup for RDS and MPX in general? I'm looking for something a bit better than my current solution which is using JMPX to generate the RDS and Stereo signal, which works but is tedious to set up. Is there a simpler way of doing things which has flown over my head . I want to keep overhead to a minimum really.

[SD-E1102]

Stereotool?

[thewisepranker]

Breakaway with Airomate.

[g33ky]

Not long after I made this thread I found "mpxgen" on GitHub, does exactly what I want with minimal overhead.

[Bton-FM]

What is overhead ?

[g33ky]

What is overhead ?

Additional programs/hardware which just add complications to the setup. Like with JMPX you'd have to set up audio loopbacks and stuff to get RDS to work.

[Albert H]

Not long after I made this thread I found "mpxgen" on GitHub, does exactly what I want with minimal overhead.

Just for grins, I configured a Raspberry Pi 3 with a minimal install of Rasbian, and added mpxgen. It took a while to sort the dependencies, then I connected a Pimoroni DAC that's able to run at 192 kHz out..... I connected the lash-up to my little test exciter, and all of a sudden I had "Test FM" on 87.7 MHz in stereo. Playing audio files from the Raspberry Pi worked fine.

The next step was to try an "Audio Injector" card - it has a pretty good ADC and a fast enough DAC.... A little buggering around with pulseaudio, and "Test FM" got audio from a CD player through a limiter..... It all works!

R-Pi3&Audio_Injector.jpg

[g33ky]

Not long after I made this thread I found "mpxgen" on GitHub, does exactly what I want with minimal overhead.

Just for grins, I configured a Raspberry Pi 3 with a minimal install of Rasbian, and added mpxgen. It took a while to sort the dependencies, then I connected a Pimoroni DAC that's able to run at 192 kHz out..... I connected the lash-up to my little test exciter, and all of a sudden I had "Test FM" on 87.7 MHz in stereo. Playing audio files from the Raspberry Pi worked fine.

The next step was to try an "Audio Injector" card - it has a pretty good ADC and a fast enough DAC.... A little buggering around with pulseaudio, and "Test FM" got audio from a CD player through a limiter..... It all works!

R-Pi3&Audio_Injector.jpg

I was trying mpxgen on my RPi1-B via a 192khz USB soundcard output since I don't have the DAC, but the Pi couldn't handle the power from the TX (only 5 watts) so just reboots. The USB works fine on a laptop with the same method. Ideally I would use a Pi as an audio source due to it being cheap and minimal, but I've only been able to get either a) reboots or b) unusable stuttering.

[Albert H]

The PI-1 is rather underpowered for this kind of use. I've used the R-Pi3 extensively as "link receivers" - running them headless inside a diecast box. Here's one using a Pi-Zero:

Link_RX.jpg

The stereo jack socket was going to be used, but I went for the two RCAs instead. It has a Chromecast power supply that also has an Ethernet port built into it, so that's plugged into the Pi Zero's USB socket rather than the power socket on the Pi Zero, so it's powered through the USB and the data is received over Ethernet. The Pi Zero is the same size as the DAC and is beneath, connected through the GPIO. As you can see, it was a quick lash-up just to get something working at short notice.

Incidentally - the PI Zero is around £5 - £15 according to which one it is (the "W" version has built-in wi-fi) and if it comes with header pins soldered into the GPIO ports. The Zero DAC is about £8, so the whole "link receiver" can cost as little as £20 complete! The audio quality is pretty damn good, with no hint of stuttering.

[g33ky]

The PI-1 is rather underpowered for this kind of use. I've used the R-Pi3 extensively as "link receivers" - running them headless inside a diecast box. Here's one using a Pi-Zero:
Link_RX.jpg

The stereo jack socket was going to be used, but I went for the two RCAs instead. It has a Chromecast power supply that also has an Ethernet port built into it, so that's plugged into the Pi Zero's USB socket rather than the power socket on the Pi Zero, so it's powered through the USB and the data is received over Ethernet. The Pi Zero is the same size as the DAC and is beneath, connected through the GPIO. As you can see, it was a quick lash-up just to get something working at short notice.

Incidentally - the PI Zero is around £5 - £15 according to which one it is (the "W" version has built-in wi-fi) and if it comes with header pins soldered into the GPIO ports. The Zero DAC is about £8, so the whole "link receiver" can cost as little as £20 complete! The audio quality is pretty damn good, with no hint of stuttering.

I have a Pi Zero (not W edition) but I believe it is the same specs as the Pi1 or am I mistaken? I did try the setup on the Zero too using a USB Hub but as expected, same result. I'll take a look at getting a DAC for the Zero if mpxgen works that well on it, since its a really cheap setup if it works.

[Polecat]

@g33ky or anyone else who may know....

I took a look at mpxgen after reading this theead. I like the simplicity of it and want to give it a try.

Don't laugh but I can't for the life of me work out how to download it, let alone how to install it and get it working.

Google searches brought up loads of instructions for an MPX gun which probably isn't something to have a lot of in your search history....

Could you offer any tips? I'm not a programmer or engineer but I was able to download stereotool and get it working.

Btw, I want to run it on a Windows 10 machine.

Thanks!

[g33ky]

@g33ky or anyone else who may know....

I took a look at mpxgen after reading this theead. I like the simplicity of it and want to give it a try.

Don't laugh but I can't for the life of me work out how to download it, let alone how to install it and get it working.

Google searches brought up loads of instructions for an MPX gun which probably isn't something to have a lot of in your search history....

Could you offer any tips? I'm not a programmer or engineer but I was able to download stereotool and get it working.

Btw, I want to run it on a Windows 10 machine.

Thanks!

I don't think it will work on a Windows 10 machine due to the difference in the way Linux and Windows 10 handle audio. Linux is free, try it in a virtual machine or on an old laptop or something (mine is running fine from a 2004 Thinkpad). Plus running it on a Linux machine means you don't have to deal with illegal Windows activators if you're sticking it on something in the field, which will cause another legal headache.

[Polecat]

Ok thanks g33ky.

The Windows machine is an old one so I'm good with that. But let's say I do put a Linux vm on it, what do I need to do to download the mpxgen software?

And when I've done that, do I have to download those 2 files it refers to and then do command line stuff to get it all working?

Reminds me of pc user computing in the 80s...but I hope you're going to tell me it's worth it!

[g33ky]

Ok thanks g33ky.

The Windows machine is an old one so I'm good with that. But let's say I do put a Linux vm on it, what do I need to do to download the mpxgen software?

And when I've done that, do I have to download those 2 files it refers to and then do command line stuff to get it all working?

Reminds me of pc user computing in the 80s...but I hope you're going to tell me it's worth it!

How old is the Windows machine? If its too old I doubt a VM would work, or at least not enough to get RDS running. To get mpxgen running requires a bit of command line (terminal) usage, but its just a few commands really. Mpxgen is a fine product though, minimalist and can just be set on a laptop and left alone. I'm not sure what two files you mean, but once you get Debian Linux up and running (plenty of google resources for that) I can help you along, shouldn't take 10 minutes. Make sure your sound card is 192khz capable though!

[Polecat]

The machine is core2 2.20ghz and 2gb with a 192k card. I only use it for serial port connection to rds and rig and back up for Traktor. Also got Stereo Tool running on it last week. Think it'll be ok for vm.

I'll give it a go anyway and appreciate the offer of help!

[XXL]

Anyone else having problems with their audio device crashing out ? Will only let me open the sound card with root (Sudo) then once it’s ran once, nothing else can access the sound card. Is there a way I can plumb a stream straight in to mpxgen rather than using jack2 ?

[g33ky]

Anyone else having problems with their audio device crashing out ? Will only let me open the sound card with root (Sudo) then once it’s ran once, nothing else can access the sound card. Is there a way I can plumb a stream straight in to mpxgen rather than using jack2 ?

ffmpeg -i "http://your.stream.address.here.com/stream" -af "lowpass=f=15000" | mpxgen+commands-go-here

[XXL]

Thanks I’ll give that a go

[Polecat]

@g33ky

Had a bit of time tonight and worked out that I can run linux within windows 10 without installing a vm.

So I made the changes in win 10 and downloaded Debian. No idea what I'm doing here but, so far so good!

Can you explain what I do next? Thanks!

[g33ky]

@g33ky

Had a bit of time tonight and worked out that I can run linux within windows 10 without installing a vm.

So I made the changes in win 10 and downloaded Debian. No idea what I'm doing here but, so far so good!

Can you explain what I do next? Thanks!

I'm guessing you're using the Windows Subsystem for Linux thing in Windows 10? I honestly haven't used it so I have no idea if/how any of it works. If you have Debian running under the system, type so:

sudo apt-get install git build-essential libsndfile1-dev libao-dev libsamplerate0-dev
git clone https://github.com/Anthony96922/mpxgen
cd mpxgen/src
make

Then just run './mpxgen' and see if it works. I have no idea if this will work or not since a) I have no experience with Windows Subsystem for Linux and b) Windows handles audio differently, though it might convert it to Windows' native format, but I have no idea.