RCD 500 won't seem to stay on FM transmitter frequency

[euge64]

I know how much you all revile FM transmitters here, but the one I have actually sounds reasonable, especially for $10. It works with any FM radio that I've tried EXCEPT the one I need it for - the RCD 500 in my 2007 Mk5 Golf GTi.
What happens is that if I tune in to it (e.g. on 88MHz), for a few seconds it sounds perfect, but then it all turns bad/static like it's not getting a proper signal. However, if I simply change to another frequency on the RCD 500 and go back to the original (e.g. 88.1 and back to 88 MHz) it will once again be good for a few seconds, then go bad again.
It clearly seems to be some kind of problem/function with the RCD 500 as the transmitter works with any other radio. What could be causing this? What can be done about it?

 

[3carmonte]

Get the head unit to an electronics/radio repair that can repair/calibrate the tuner in the Head Unit. I found a business here in the States that specializes in OEM car radios that just fixed two issues in my Head Unit. Use this YouTube video to remove it from the dash.
https://www.youtube.com/watch?v=ko5-G9YwTpE

 

[euge64]

Get the head unit to an electronics/radio repair that can repair/calibrate the tuner in the Head Unit. I found a business here in the States that specializes in OEM car radios that just fixed two issues in my Head Unit. Use this YouTube video to remove it from the dash.
https://www.youtube.com/watch?v=ko5-G9YwTpE

Thanks. However, the radio tunes into any other normal radio station without a problem, which makes me think that the tuner is probably fine. Is that a fair assumption? This really has me stumped!

 

[3carmonte]

It clearly seems to be some kind of problem/function with the RCD 500 as the transmitter works with any other radio. What could be causing this? What can be done about it?

I'm just putting myself in your shoes sir and playing "what would you (I) do?" Your thought process is logical. If "the transmitter works with any other radio", exhibiting none of the symptoms you described through the car radio, what else could be at fault but the Head Units tuner or the antennae?

The only experience I have with short range FM transmitters to radios are those at the old drive-in theaters (which worked great) or the public service information feeds about road conditions in different areas along highways which always seem to have interference...

Can you change the frequency that the transmitters carrier uses from 88MHZ to another (unused) channel on the radio and test it there? Say, one right in the middle of two stations that come in crystal clear and solid?

 

[euge64]

I'm just putting myself in your shoes sir and playing "what would you (I) do?" Your thought process is logical. If "the transmitter works with any other radio", exhibiting none of the symptoms you described through the car radio, what else could be at fault but the Head Units tuner or the antennae?

The only experience I have with short range FM transmitters to radios are those at the old drive-in theaters (which worked great) or the public service information feeds about road conditions in different areas along highways which always seem to have interference...

Can you change the frequency that the transmitters carrier uses from 88MHZ to another (unused) channel on the radio and test it there? Say, one right in the middle of two stations that come in crystal clear and solid?

Unfortunately, it's the same story on any frequency (I should have said so before). It's like the signal from the transmitter is slightly different to a normal FM signal which upsets the RCD500 but any other radio ignores. Or maybe I'm just making that up. Once again though, thanks for your help.