miker2

this is for the early c4's'.gm used to sell a reception improvement kit but it's no longer available.not to worry.the kit only consisted of two double 800mm wires and a few screws and zip ties. i found an old kit in my garage the other day and scanned the instruction sheets. see https://skydrive.live.com/redir.aspx...24FD3CD9DE!278 . the other sheets in the instructions were only how to record before and after reception results.

oldalaskaman

another upgrade for that is to switch to a later year antenna, a bit spendy, but you lose some of the other issues also

Wezel

Has anyone tried replacing the power antenna with one of these?


http://www.dakotadigital.com/index.c...rod/prd105.htm

Larry/car

I did the ground plane mod on my 1990. It did make a difference but didn't get the reception I was hoping for. Made the radio usable. I finally gave up and replaced the car with a 1995. The 1995 unit really works great, pulls in stations that my 2004 Chev. truck doesn't.