Thread: 11 meter beam
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Old July 18th 08, 12:50 AM posted to rec.radio.amateur.antenna
Dave Dave is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 797
Default 11 meter beam


"Stan Cooper" wrote in message
...
Hello I hope I'm not intruding by asking for advice on a CB antenna but I
figured this would be the group to ask about such things for the straight
scoop. At any rate I'm considering a store bought beam with both vertical
and horizontal polarization and my choices are limited to these two below.
(not many being manufactured anymore)

The Maco has a 16 foot boom and an advertised gain of 12.5 db, while the
JO GUNN has an 8 foot boom and an advertised gain of 14.5 db. I know there
is a lot of smoke and mirrors involved with advertised gains and so my
question is...is it possible for the JO GUNN to perform as well as the
Maco antenna?


well, there are a couple possibilities... first the Maco could be poorly
designed so it doesn't perform as well as the JO GUNN, or the Maco
advertisers could be more honest than the JO GUNN ones are... or the JO GUNN
is extremely well designed, or their advertisers aren't as honest as the
Maco ones are.

OR, they could just be comparing to completely different references, thats
the basic problem with antenna gains, they usually don't tell you what they
are compared to if the JO GUNN was compared to an isotropic radiator where
the Maco was compared to a dipole that buys them a couple db right there.

confused yet? there's even more...

Maybe the JO GUNN is measured over real ground at the best height and
elevation angle they could find... and the Maco was measured in free space.
Measuring an antenna over real ground and finding the max gain lobe could
give the JO GUNN a whole bunch more gain than the free space Maco... enough
to make up for half the boom length and a worse design put together.

So there you have it... my suggestion, put up a ground plane to talk to your
local buddies and get a ham license so you can legally and openly talk
around the world.