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Old April 21st 04, 04:08 PM
John Smith
 
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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.

Idea 2, May almost work, as the 446 is almost the third harmonic of 146 and
the antenna would be resonant again, 438 is 3*146 only a 2% change, close
enough to try it once. Bandwidth of antenna is the critical factor, tune
for 3/4 antenna of 446 first and then see where it came out near the 146.
Then split the difference between the two, a sweep of return loss would
show you the antenna bandwidths, and if it is possible, If no go, try Idea
#3

Idea 3, Other cases -- use a dual ban antenna approach, put a loading coil
in the middle (airspace turns), the bottom part is the 446 1/4 wave, and
doesn't "see" the top part due to the coil. Then the full length with
loading coil is equivalent to a loaded 1/4 wave at 146. Start with a 146
and center loading coil to shorten the 146 lengthwise. Then tune the lower
rod for 446, so the coil may not end up in the center, but it will be right
on on both frequencies. (should not take much of a coil since it is only 2%
off) I did a triband one time with two loading coils for Low Band, VHF and
UHF. Had a splitter designed to split off to the three radios in the trunk
too.

Crazy ideas get patented!



"JLB" wrote in message
.. .
Would these work, or am I crazy? I would also entertain the idea of both
being crazy and the ideas working ;-)

Take a normal 146 MHz quarter wave mobile antenna and heat shrink a piece

of
insulated wire to it. The wire would be a half wavelength., more or less,
at 446 MHz. Trim the wire for minimum SWR at 446 MHz.

Another idea. Take a 446 MHz quarter wave wire with one end uninsulated.
With the uninsulated end up, attach it to the 146 MHz quarter wave with

heat
shrink. Adjust the position and length of the quarter wave wire for

minimum
SWR at 446 MHz.

--
Jim
N8EE

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