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Old January 26th 04, 05:31 PM
Cecil Moore
 
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Jeff wrote:
But the difference between the smaller and larger magmounts is what
puzzles me. Shouldn't both mounts give similar SWR readings?


A thought - mag mounts are designed to work on a painted surface
through capacitive coupling. If your metal box is unpainted metal,
you might be getting a DC path through one mag mount and not the
other.
--
73, Cecil http://www.qsl.net/w5dxp



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Old January 27th 04, 04:50 AM
'Doc
 
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Cecil,
Paint the airconditioner??
'Doc
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Old January 27th 04, 07:26 AM
'Doc
 
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Jeff

-----
Long story short, I'm trying to figure out why the metal AC box
functions just fine for a smaller magmount, but not the larger one.

-----

One possible explanation is that it isn't the AC's box that's
different, but the amount of capacitive coupling furnished by
the
larger magnet mount. One way of finding out is by extending the
length of the antenna slightly to compensate for the greater
coupling.
If that lowers the SWR to a reasonable level (or even if it
doesn't, but
does lower the SWR), then you know you're onto something and can
'fiddle' with it till it's 'right'.
'Doc
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Old January 28th 04, 01:33 AM
Stephen Cowell
 
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"'Doc" wrote in message ...


Jeff,
Try using the AC as a mounting point for a horizontal
bar running out far enough to mount an antenna on, such
as some type of 'base'(?) antenna.
All antennas have to be tuned and/or impedance matched.
Any antenna near obstructions will have undesirable
characteristics compared to the same antenna in the 'clear'.
I think what you're seeing is fairly 'normal' for your
situation. Good luck...
'Doc


What Doc said... your high-gain base antenna
has phased sections that interact badly when
their near-field radiation is interfered with.
Get ye a yardarm! Something like that, to
get the antenna out farther.
__
Steve
..


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