Handheld radio antenna adapter cable

[JrBirdman]

Fellow Aviators,

My Pacer came wired with a small adapter box mounted behind the panel. It's function is to allow a "patch cord" to go from your handheld antenna connection to plug into this little box, where it interrupts the antenna connection to the panel mounted radio and allows the handheld to use the aircraft external mounted VHF antenna. The box and cable are sold by ICOM and Sportys for $75. I don't need the box just the "patch cord", but can't find it sold separately. It is definitely an "ood-ball", using a standard BNC quick disconnect on the handheld in place of the "rubber-ducky" antenna. The other end is just a standard 3 segment 1/8" phono plug like your Ipod earbuds use.
I believe the tip of the phono plug breaks the main radio antenna path and completes the connection for the handheld antenna on the middle segment of the phono plug.

Anybody know a vendor who sells just the adaptor cord?
Anybody have one of these that can unscrew the terminal and confirm the tip is dead and the middle section carries the antenna RF, and the third segment the coax ground? Then maybe I can fab one up from parts.

I have read this is a not an ideal set-up. The switch box is subject to corrosion. The phono plug doesn't provide the 50 ohm spec. But it still may work better than the rubber ducky and I'd like to try it out anyway since it is already in there.

Thanks all, REID

[MN_flyer1]

Well I cannot confirm the connection you have but this would be my guess. The small plug should be mono with the central line of the coax connected to the tip and the base connected to the shield. In almost all applications of the 1/8" plugs the base is connected to shield.

Tim