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Old December 2nd 05, 01:05 AM posted to rec.radio.amateur.antenna
Bob Miller
 
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Default Mobile 2m/70cm antenna

On Wed, 30 Nov 2005 11:24:47 -0800, "Rod Maupin"
wrote:

I recently bought a Larsen 2m/70cm NMO mag-mount mobile antenna for my
truck. It's the first time I've ever owned a mobile antenna because I don't
do that much driving (I work from home). I don't have a mobile radio in the
truck, I just have an HT.

What I wanted to do was hook up my Icom W32A to the mobile antenna when I'm
in the truck. So, I put the mag-mount on the middle of the pickup roof and
started driving. I compared the mobile Larsen antenna to my Diamond RH77CA
HT antenna. What I noticed is that with the Diamond antenna on the HT
inside the truck, it consistently pulls in more signal (on both bands) than
the Larsen mobile outside the truck. The Diamond antenna is of course an HT
antenna, so it's optimized for HT use.

Is this normal behavior for a mobile antenna hooked up to an HT? If it's
not normal, then this is not that great of a mobile antenna.

Rod KI7CQ


When I bought a similar antenna, a Larsen 2m/70cm mag mount (mine is
about 20 years old, but may be the same exact model as yours) anyhow,
I had to cut the vertical element with a file to get the SWR down,
using a Bird wattmeter. The antenna, as it came from the factory,
needed quite a bit of diddling before being resonant.

Have you checked SWR, and/or adjusted the vertical length?

Bob
k5qwg