I decided a while back to go out and remove the 6 disc changer from the PT today, and also took out the factory Sirius unit.
I have a JVC headunit, Sirius and I-pod adapter to install. One thing I was hoping to do was to not have to have another antenna up on the roof, as the factory one is already there. After talking to stereo shops and reading online and hearing "It can't be done" I decided to dig into this. Turns out this was extremely easy.
This is the JVC SIR1 unit. It's new home is there the old sirius unit was.
There are 2 connectors, a white and blue one. The white one is the terrestrial antennas, and I don't believe they are used any longer. We want the blue one.
It's a little blurred, but the antenna plug inside the blue connector looks the same as the newer unit. It is. I talked to someone who says they never changed the guts of the plug.
All you have to do is simply unclip the little white cover off the blue connector, and simply remove the wire. This is what you should have. Just plug that into the antenna connector on the aftermarket unit, and make sure you secure the unit to the bracket, and you will be fine. Some people put a little hot glue or tape on it, but that's up to you.
Turned the power on to the radio, and all is well...and only one antenna... Hope this helps anyone who didn't know how easy this is. Works like a charm, and has been now for 2 months!
Shawn