[Antennas] On The Glass Antennas

[wb5itt at earthlink.net]

Tis true in new autos.....passivated glass is glass with metallic flakes in it....to help reflect heatback out (new version of "tinted" glass).....its been around for years....friend with a 94 full size Chevy Tahoe found out his side windows had that...the front windshield still had tint only in the upper section...
IF you have an on glass antenna, you can test by holding both pieces of the antenna together and using a weak signal as a test reference....then sliding the pieces over the glass where you want to put it...(someone may have to hold the inside or outside piece in this case while you hold the other) see if there is any signal loss...
passivated glass can have up to 10db loss through it....

Remember MOST on glass antennas also use HI Z to couple thru the glass...ANYthing on the field will affect it as they will be lower impedance and can act as a resistor to gnd....I ONLY use Larsen ONGLASS antennas as they work in LOW impedance mode through the glass...thus anything external usually does not affect them..
(did a test with a 100watt radio with a Hi Z on glass antenna; found it was 5-10db worse than a 1.4wave on the roof.....Larsen was almost no loss...the Hi Z eventually fell off during testing due to the glass being heated! The Larsen ran fairly cool and so was the glass!)

Chris
WB5ITT

-----Original Message-----
From: Doug Weaver <dweaver at dtnspeed.net>
Sent: Aug 19, 2004 5:45 PM
To: antennas at mailman.qth.net
Subject: [Antennas] On The Glass Antennas

Is any one out there using a on the glass antenna on the side window of a
2002 Ford Explorer?  While looking through HRO catalog I found a 2M/440
glass mounted antenna made by ATOC Technologies. In the product description
it states (Note: Some newer automobiles are equipped with "passavated glass"
which does not permit on-glass antennas to work properly)  The owners manual
says nothing and a 20 minute phone call to Ford also comes up with nothing.
I also tried an e-mail to the antenna manufacturer and got no response.
This is the first time I've heard of this issue.

Doug....KD8KX