From digest.v7.n163 Sun Aug 24 14:36:29 1997
From: antenna <raul_at_antennaworld.com>
Date: Fri, 22 Aug 1997 09:53:45 -0500
Subject: antennas-diversity- re-posted

Here is a reply I wrote to somebody here last month and posted on the = car digest. In another posting I said this was never posted but some of = you wanted to see it so here is a re-posting. Plus I just read = somebody's post about aftermarket radio and poor reception. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^SEE =
BELOW^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ I noticed some complaints about bad reception in here today and wanted = to add some comments.

The antenna system is a brand "FUBA" who is the leader in hidden = electronic am/fm receiving antennas for moving vehicles. The company = where I work was the Fuba aftermarket importer from the late 80s to = early '90s. Fuba div was purchsed by Delco 2 or 3 years ago and they are = now adding some hi tech antennas to GM cars.

I do have some block diagrams of 88-92 BMW antennas in the glass. At the = time it was only the 5 and 7 series. Plus many VW group cars too.

The main thing I know is that the computer in the C pillar has 2 to 4 = sep antennas connected to it and constantly looking for the strongest = signal to send to the radio. It knows which is best because of an IF = (intermediate freq) small coaxial cable coming from the radio to the = computer. The computer also contains RF amps for each antenna ( or a = matching circuit)

If your reception stinks, maybe the IF line is disconnected or broken. = Then the system defaults to a single antena ll the time, even AM band. = Or if you dumped the OE radio for a fancy Sony/Pioneer/etc, same thing. = No IF signal.

I dont think the IF line is data. I should be a voltage varrying which = the computer simply reads. Maybe you can check that with a dig voltmeter = but its just my educated guess.

Another thing is TINT. I did not realize it until I got metalized tint = on my E-34 and reception went down 30%. It was bad for a few days until = I got used to it. Or maybe the amp made itself stronger? I have = excellent reception these days, after 2 years of the tint job. Very = strange.

I wont be able to get updated '96'97 info as Fuba is now solid with the = OEM business only and we lost our inside friends. Or they are there but = with hands tied...

Regards raul_at_antennaworld.com