[amsat-bb] Re: Good mobile antennas to use
bruninga at usna.edu
Thu Sep 15 10:07:44 PDT 2011
I donno. The only 1/4 19.5" antenna I ever used I just drilled into the
roof above the dome light and installed an NMO mount and simple whip. For
conversion of an existing mount, if it is a 5/8's wave vertical (most
mobiles are) then there is a matching network in the base.
The little tiny micro whips are ideal, but most of them now are being made
as "dual band" which then destroys their 7 dBi gain above the horizon.
No easy answers here.
From: Ng, Peter [mailto:Peter.Ng at bccdc.ca]
Sent: Thursday, September 15, 2011 12:47 PM
To: 'Bob Bruninga '; AMSAT-BB
Subject: RE: [amsat-bb] Re: Good mobile antennas to use
But this is not what a 19.5" whip does. The 1/4 (3/4) wave 19.5" whip does
not have gain on the horizon (so it is rarely used for terrestrial mobile)
but its pattern is ideal for satellite work on high passes. It does NOT
then have a null in its pattern that causes the "crappy" contacts, and it
does have plenty of gain above about 25 degrees.... and it is a smooth
pattern.... not like the multi lobes of a standard mobile gain antenna.
This is off topic and didn't want to start something on the list... :), but
can I convert my current magmount gain antenna simply by replacing the whip
or is the "gain" stuff in the magmount itself? If so, would any thin steel
rod do? I'd really like to give this a try!
73's Peter VE7NGP
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