Post by Richard ClarkOn Thu, 23 Oct 2003 10:38:15 -0400, Deane Charlson
Post by Deane CharlsonHello,
I have been using single-band half-wave dipoles for years. I would like
to try some multi-band wire antennas and compare performance. I am
considering using an Off Center Fed Dipole or a G5RV or a Carolina
Windom. Any thoughts or experiences with these antennas as compared to
a half-wave dipole?
--
http://web.wt.net/~nm5k
If strictly comparing performance, all three are inferior when compared
to the coax fed dipoles. To be honest, I've tried all of the antennas
you mention, and I have no use for any of them. I thought overall, they
were pathetic. I agree, if you want to run all bands, just feed a dipole
of the lowest band you want to run with ladder line. If you use a tuner,
use the very least inductance to get a usable match. That will greatly
reduce tuner losses. Nothing you try will beat a coax fed dipole for
pure efficiency, unless you use a no-tuner method like Cecils no tuner
ladder line setup. But careful use if the tuner will leave losses low
enough to not really worry about. Well, unless you are like me, and want
every last drop....I stick with parallel dipoles fed with a single coax.
At the moment I have 80/40/20 dipoles on one line. I can use the tuner
on other bands if needed.
But those bands I get: no tuner needed, no tuner losses, the advantages
of coax, and a normal dipole pattern on those bands. My total system
losses are very low. I don't like using a tuner as you can probably
tell. :/. I'll avoid it like the plague if possible.
The OCF is prone to common mode problems. Same with the windom which is
basically the same thing. The average storebought windom and G5RV's
suffer from excess feedline losses due to the micky mouse feedline
design. IE: coax to balun to ladder line to antenna...Add tuner loss for
all band use...What a micky mouse mess...:( I compared coax fed dipoles
to both a storebought windom and a storebought G5RV at previous field
days. Ate em for lunch. I mean absolutely tore em a new one...You could
see a 2 S unit difference just in the efficiency difference. On theirs,
everything would drop. Noise, signals, everything. Pattern was not an
issue. Was a painful sight for the owners of those antennas. They had no
clue they were that inferior until I A/B'ed those puppies using an
antenna switch. :( You can improve the performance if you design a
better feed system. IE: dump all the garbage, and run ladder line the
whole way. MK