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Diversity Antennas and AVICs

By jonbruce · Jun 24, 2009in General💬 3 posts👁️ 958 views
Posted Jun 24, 2009 · 17:04 UTC#1

What is the collective opinions on how best to match a diversity antenna (typically found on Toyota's) with AVIC F90BT systems? AKAIK, with a diversity antenna there two things I should do - first make sure it is correctly powered (blue wire I believe) and second find a way to splice together the 2x antenna feed from two feeds to one which will plugin into my HU. I think i need to find a splitter that would take the 2x female (both sizes) to male connections for this work.

 

My FM/AM/HD Radio reception is really poor, much worse than that of my factory radio which frankly is a huge disappointment.

 

If anyone has suggestions as to what I can do here, or where I could source such a splitter, please let me know.

Posted Jun 25, 2009 · 01:51 UTC#2

Jon,

 

Many (all?) late model VW's also have the diversity antenna. My 06 Jetta does and suffers the same reception problems you mention. I do not know of a splitter for this and am seriously considering installing a OE type roof mount antenna.

 

I hope you find one before I drill a hole. Good luck.

 

Charlie

Posted Jun 25, 2009 · 02:43 UTC#3

A factory diversity radio switches back and forth between the two antennas, using the one with the strongest signal. This way it can companesate for vehicle position, and the waveforms of the signal. Ever wonder why you can get good reception on radio if you just move it a couple of feet? It's basically an wave, either intersecting with it, or it's going right over you. An aftermarket radio does not have these capabilities of analying two seperate antennas and deciding between the two..

Simply splicing the two together may even degrade the signal. Forst, there is roughly a 4db lose with each connection. Second, most radios are tuned for using a mast 21in, no more and no less. Adding more of antenna will through things off. It would be like adding a 5ft mast to your existing antenna mast found on older vehicles.

For the toyota, just use the larger of the two antenna connections, and quit worring about it.

We are also in the 21st century now, there a all kinds of alternatives to basic FM and AM.