I know that some CD Changers are made to replace stock stereos that don't have special inputs for them by using an inline antenna cable (antenna goes into adapter, adapter goes into antenna jack of stereo.)

I'm assuming how this works is that once the CD changer is powered that it disables the signal from the antenna and somehow floods the player with a signal that works on all frequencies? I don't know, nor need to fully know those specifics, but my question is as follows:

Is there a cable/device similar to what this achieves that is open to an RCA type input? I.E. it would just be a cable dangling out from my center console until you plug something in (say, an iPod for example) that would be unpowered, thus using the antenna still, until something powered was attached and took over the signal and cut out the antenna.

I've got no idea what such a thing would be called, and haven't had any luck searching...

 

I think what you are describing is an FM modulator. I just installed the audiovox unit in my '95. It works great for my mp3 player. basically you connect it inline to the incoming antenna signal to the bose radio (using a nissan diversity antenna adapter) and then you have RCA jacks to which you can plug in any audio source. There is a switch that turns on the modulator. The modulator operates on 1 frequency that you set the radio to. Reception is excellent and is hard to tell from CD quality. I got all 3 of the products needed from ebay for about $35 total shipped. I plan to add a relay that will lower the power antenna when the modualtor is being used.
http://www.crutchfield.com/S-j9fm0IL...ssan+diversity
http://www.crutchfield.com/cgi-bin/S...=12040Ni20&s=0
http://www.circuitcity.com/ssm/Audio...oductDetail.do