Stereo Tool

Hello everybody,

I was wondering is it possible in Stereo Tool to change the RDS carrier frequency from 57kHz to a custom one, example 19kHz, like it is possible in Airomate ? I am asking this question because my FM transmitter won't accept frequencies as high as 57 kHz for RDS modulation. I tried moving the RDS carrier manually to 19 kHz on Airomate and it worked on my radio, the RDS showed up. On ST, however, it won't work, as I said, I need a way to move the RDS carrier to 19kHz.

Thank you for your answer, greetings from Croatia.

Huh? How can RDS work if it's set at 19 kHz??? Only thing I can imagine is that you're sending it in at a single channel, it gets stereo-modulated at 38 kHz by the transmitter and then ends up at both 0 and 57 kHz. RDS really needs to be at 57 kHz otherwise no radio will recognize it.

Hello.. (pozdrav )
First of all .. what does it mean that your transmitter cannot accept RDS? Every transmitter with mpx input will "accept" RDS.
That can just mean one of 2 things; that your are not using MPX input or your soundcard is not working at (or not capable for) 192kHz sample rate.
Also I never heard such thing that you can 'move' RDS from 57kHz to 19kHz or any other place. Simply things does not work and not maded like that.
More strange is that you say that with airomate you can have RDS on your tuner.

So, check soundcard with ST. be sure to set 192 or 176.4kHz for 'sample rate' and check does your trsnsmitter input is really "MPX" input.

Thank you guys for your super quick responses !

I'll try to depict what I'm trying to say with pictures, here they are:

This is the RDS configuration I set up in Airomate settings.



This is what I get on every RDS compatible radio set:



I have read somewhere that the transmitter needs to be completely mono to work properly with RDS, stereo encoding and such. However, my transmitter is already modulating Stereo, so I'm suspecting that there is a problem hidden somewhere in my transmitter configurations. Although I can't do much to alter the transmitter options, it's pretty much plain simple and I don't really think there is a way to switch off stereo modulation inside the transmitter.

I'm sorry if this is somewhat confusing, but I'm doing my best to explain what's the matter I'm having. Thank you again! Lijepi pozdrav!

So i was right...
You are using L or R input on transmitter. If you want to put RDS in it and so use external Stereo Coder you need to have pure MPX input on transmitter and to use that instead.

So, am I correct that your RDS is entered in one of the two channels? I expect that if you broadcast silence, you'll hear weird low frequency sounds - that would be the RDS copy at 0 Hz...

I'm using a 3.5mm stereo TRS connector to connect my transmitter to computer. As far as I can hear, the sound is stereo.Can you recommend me some Stereo Coders, is that a software you mean? Thank you.
I hear that sound, you are correct ! Sorry, but I don't really understand what do you mean my RDS is entered in one of the two channels, you mean Left and Right audio for stereo sound ?

Stereo Tool contains a stereo coder! So ideally you should turn the one in your transmitter off. And then just use Stereo Tool for everything. That gives better results too, since you can also use the composite clipper

Yes, I could have suspected there is a problem in my transmitter... So I guess I better start finding a solution how to switch stereo coding off in the transmitter itself. I believe all ST functions (RDS..) will work after I do so? Thank you for your responses Hans and Bojcha ! Appreciate it!

Yes, assuming that the transmitter doesn't also do other things such as pre-emphasizing. Basically the signal that comes out of Stereo Tool should be transmitted without any changes.