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Old 08-16-2014, 04:55 PM   #15
NN5I
Carl, nn5i
 
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Join Date: Sep 2011
Location: Tallahassee, FL
Posts: 1,441
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Quote:
Originally Posted by Mr. Ham View Post
You have your antenna mounted too low on the vehicle.
And I suppose, if I mounted a ground-mounted vertical in my back yard, you would complain because it was ground-mounted instead of elevated. But when one elevates a vertical monopole, one must also (usually) install elevated radials so that the antenna will be mounted near its ground plane. Therefore, nonsense, say I.

If it were on, say, an all-aluminum trailer, you would be nearer right, for (with the antenna mounted low) the aluminum body would tend to block the signal (and also detune the antenna by bypassing it capacitively). But my motor home's body is mostly fiberglass and, for RF, doesn't exist.

This antenna is some 10-12 feet tall depending on frequency. I can see it now, mounted on top of my 12-foot-tall motor home. I would have to use a tilting mount if I ever wanted to go anywhere, and certainly couldn't operate when moving. Also it wouldn't work worth a flip anyway, being some 12 feet above its ground plane (the frame of the vehicle). That's more than 1/3 of a wavelengh at 20 meters.

But thank you for your advice.
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