Stereo Tool

Is it possible to implement this into stereo tool? It appears to use spectrum above RDS.
http://en.wikipedia.org/wiki/FMeXtra

It seems that maybe this could be done with HEv2 and simply add it to the output on the MPX.
http://en.wikibooks.org/wiki/MeGUI/Comp ... iles/Audio

Looked at it *very* quickly, I saw that it is at freqs above 100 kHz which only 384 kHz capable sound cards would be able to generate.........

I would be willing to test this if it were implemented.
It can work as well in the space above RDS but below 100khz.

hvz: I was able to get stereo tool working at my FM tower and have actually replaced my Pira 1322 unit with it. I'd love to see the ability to play AAC streams directly over stereo tool on SCA 1 for test purposes. Is there any way I can work with you to implement something like this.

My objective is to also build an FM reciever that is capable of decoding the AAC streams, as well as having future implementation with opus.

I do have access to a large number of FM stations that would implement a similar system IF we can build this one test system.

Are you interested?

Hm, so you want to put the stream data itself in there? Above 60 kHz (and probably below - say - 85, otherwise I think most sound cards will be problematic, not sure how high you can really go because I have never tested it).

I might be interested, but I fear that doing something like this will take a lot of time (which I don't have - I could potentially hire someone for it but then we really need to be talking about a LOT of stations), and chances are that the company that's doing this now won't give out the details needed to implement it. Also all the info that I can find is at least 5 years old, and what Wikipedia says (that it's compatible with HD) can't be true because HD is broadcast using a completely different mechanism - the best possible thing would be that radio's that can receive HD can also receive this signal but I really doubt that.

What would your goal be? That normal listeners can tune in to this extra signal? Or do you want to send audio to stores etc. similar to the analog SCA channels? If so it might be a lot easier to keep things analog! If - instead of the (standard) 7 kHz wide SCA signal, you would use 60-75 kHz (15 kHz of audio, AM mono single sideband encoded with a synchronization signal) things would be much simpler.
Decoding the stream isn't the issue, but you would also need to be able to convert the audio signal to bits, which is more problematic - that's probably the issue that this VuCast solves.

I believe we could get it working with some work.

The purpose is to service an alternative avenue for FMExtra to stations whom couldn't afford the 8grand for a Vucast computer that encodes the data and outputs via a 192k soundcard.
I agree if its going to take a long time maybe it could go on the back burner, but I could see the potential for ST to generate a large profit off of this.

Even one digital subchannel on the FMExtra spectrum would be monumental.

I'm pretty sure the digital radio sees the carrier frequency of the digital stream above the RDS spectrum, reads the encoding, and decodes it. I would certainly be willing to test if you could feed it a raw stream from say a mp3 at first.

Well, first of all the description of how FMExtra works would need to be public, otherwise there's no way to do this.

But, based on what I read, HD radio's do not support FMExtra so you would need to buy a special radio. And I saw post from stations that wanted to support FMExtra who couldn't find any company that wanted to sell them a receiver. Almost all posts about the Subject are from 2006-2008. So, it really sounds as if it's dead. ..

How about this. Is there any way to encode the signal into DRM? I've got access to the SCA channels on several full power FM's but can't find any FMExtra or DRM gear for low cost.

DRM and FmExtra seem to be competing formats, so I would guess no. Still, even if you could get it to work, FmExtra appears to be a dead format - I can't find anything recent about it and support in receivers appears to be nearly non-existent. And if you would enable it anyway, be aware that normal FM reception of your station will suffer from it.