I'm in the middle of installing a Sirius radio in my '86 560SL. I mounted the disc-shaped antenna, for now, on the front edge of the trunk lid, per the instructions. The receiver will be inside the glovebox.

The unit came with a 2" long 'FM out' transmission 'antenna' that I assume is to help transmit the signal to the car's head unit on a selected unused FM station.

My question is first, does the signal from this tiny antenna go directly from the Sirius receiver to the radio, or does it go to the cars' regular antenna first, and then through the antenna lead from the trunk to the FM radio?

I'm curious because the dash is basically a steel encased chamber over the glovebox and I wonder if the signal will get to the trunk-mounted Hirschmann antenna, or if it will go directly to the radio right next to the Sirius unit.

Secondly, since my Blaupunkt radio doesn't have an external input jack, would I get better reception with an antenna adapter harness that takes the signal directly from the Sirius unit and feeds it into the antenna input at the back of the Blaupunkt?

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1986 560SL
2002 Toyota Camry
1993 Lexus