Bob Wood wrote:
Thanks for the comments Mark. I do appreciate your taking time to give me
some advice. I only have a limited space around my home so can't put up a
one wave per side. I am currently using a sloping dipole and doing fairly
well but need to improve the reception to cover Texas, Arkansas, Oklahoma
and Louisiana for Navy MARS region nets.
Where are you now? Are they all in the same direction?
I saw an article somewhere that
indicated a V Beam 3/4 wave on a side would provide 3 dB gain over a dipole
in one direction.
Dunno about that. Sounds a bit fishy to me, but I'm not saying it's
impossible. But consider this...
An extended double zepp, which is .64 wave per side, has almost that
exact gain over a dipole in TWO directions. If you only need 3 db, that
would work, if f/b ratio is not a problem. If you need some f/b and
gain, I would use an array of two dipoles parallel.
I will have to research it some more but it is really
difficult to find information on V Beams on the net. If you do discover any
more info I sure would appreciate you sharing it with me. Thanks again,
73, Bob
I have some in books, but I don't know what you want to know
specifically..But I don't consider a 3/4 wave per leg antenna a V beam.
It has none of the properties of a true V beam, which is a form of
traveling wave antenna. To really act as a V beam, and have decent gain,
it must be a few waves long on each side.
A single long wire is the simpliest form of traveling wave antenna. It
must be at least one wave, and should be several. A V beam is two long
wires connected at one end. A rhombic is two V beams back to back. They
are all closely related. The longer the V beam or rhombic in WL, the
narrower the angle between the wires should be.
A 3/4 wave per leg antenna folded into a V, is just a 3/4 wave per leg
dipole in a horizontal V config...Having straight like a true EDZ, and
using only .64 wave per leg, instead of .75, should actually give you
the most gain you can get with that antenna size. Thats the way I see it
anyway...I'd forget about V beams. You probably don't have the room for
a real one. There are better options like the phased dipole array, or
the simple EDZ itself if f/b is not an issue.. I've run the phased
dipoles on 40m. It's almost like having a 2 el beam that can point in
two directions. More than that if you play with the different phase
options. That would give you your wanted gain easy, and about a 15-20 db
f/b ratio to boot.
MK
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