[Mobile-Portable] Through the glass antenna on double pane windows

[Art Clemons]

 >I have a Larsen through the glass antenna on my car.  However, it was
 >designed for use with a cell phone.  If I were to replace the whip with
 >a 1/4 wave rod for 2 meters, will it work?

Most likely not, since most such antennas use a half wave length rather 
than a quarter wave for a variety of reasons, not least of which is the 
matching in most such antennas.  I suspect that a reasonable sized 
capacitor for 800 megs or so will be too small for 146 megs.  Still, if 
you already have one, nothing beats actually experimenting to find out 
the answer.

 >Can I use the same mount on the double pane glass windows typical in
 >most houses nowadays?  I've heard conflicting comments.  One says no 
 >because it works only if its on a single sheet of glass.  Another
 >insisted that it will work.

Through the glass antennas work on capacitive coupling with one plate 
being moved to produce a reasonable match on whatever band is being 
tuned at the time, so the answer really is the old lawyerly, "it 
depends" answer.  If the distance in the between the panes is conducive 
to a match between the two plates, then it will, otherwise it won't. 
Also please note that with capacitive coupling, a half wave works better 
and is more likely to produce a reasonable match.