I have the exact antenna described on Idea # 3 ,, I have it on a magnetic
mount, I use it for a bicycle, I have it magnetically mounted on a plate of
steel on the back. I use it for 2m and 70cm, 2m SWR is flat and 70 SWR is
very low, but I also use 156 megs a lot also. I was able to obtain a very
low SWR on all three by folding metal tape in half like a flag at the bottom
of the whip, about 2 inches up. 2 inch tape, tin foil tape for duct work
(not duct tape) it is aluminum foil but about 6 mil and very tacky. I cut it
to achieve a low SWR (about 6 inches length). So its like a metal flag, 2
inch by 6 inch length. Without it, I had very high SWR on the marine band.




"JLB" wrote in message
...


"John Smith" wrote in message
...
Idea 1, would probably not work much at 446 as current would have a hard
time to flow into attached insulated wire. general problem with most
mobile
antennas is getting enough RF current to flow out into them.


There are two ways that Idea 1 can be thought of:

A. The extra wire is a half wave dipole coupled to the 2 meter quarter
wave. By some magic, it resonates and radiates on 446 MHz as a half wave
dipole.

B. A shorted quarter wave transmission line is an open circuit. So is a
half wave open circuit transmission line. The extra wire next to the 2
meter quarter wave acts like an open half wave transmission line,
effectively isolating the upper part of the 2 meter quarter wave when
operating on 446. When the wire is positioned properly, the bottom part
of
the 2 meter quarter wave will act like a 446 quarter wave.

Jim
N8EE

to email directly, send to my call sign at arrl dot net