> The bigger question is - why are you putting up a big Mosley antenna?
> Have you already purchased it or are contemplating it?Just about any other
> antenna out there will be a better performer.
I've had several inquiries into my comment on Mosley antennas. As you
could tell, I'm not a big fan of them. My opinion is that they don't work very
well. Good SWR? Yes. Robust construction? Sure. Performance? Not that great.
I install ham towers and antennas professionally and I've worked on over
100 different stations. I have also received email from and talked to hundreds
of people about antennas (including recognized experts in the ham antenna
field) and have used some of them myself.
There are two types of Mosley owners. The first is the one that feels like
it's a pretty good antenna. I think there are 2 reasons for this. First is
that they don't have another antenna to compare it to (like a dipole or other
yagi and not a trapped vertical) so when they work something, it must be
working FB. The second reason is a justification that something that big and
that expensive must work.
The second type of Mosley owner is the one who has used it, found its
deficiencies and will make you a heckuva deal on a slightly used one! There
are a couple here in the Seattle area that would like to talk to you if you're
interested in buying one.
I guess the clincher for me as a contester is that there are darn few
competitive stations that use them. There are no stacks of Mosleys at ANY
serious contest station unlike TH7's, KT34XA's or even C-3's. These stations
don't even have ONE Mosley at their station. Why not? THEY DON'T WORK!
Okay, Steve, that's nice hyperbole but do you have any empirical data to
back up your claims? Funny you should ask. N0AX and myself have run field
tests on a couple of multiband antennas. These tests were conducted under
controlled conditions and used a reference dipole at the same height so the
figures are dBd. Here's what we found with a PRO77:
14.025 0.0 gain dBd
14.100 1.0
14.175 1.0
14.250 -0.5
14.325 1.0
21.025 4.0
21.125 4.0
21.225 4.0
21.325 3.0
21.425 0.5
28.050 -3.0
28.250 -1.5
28.450 -1.5
28.650 -1.5
28.850 -2.0
Yes, there are some negative gain figures. Doesn't look like the catalog
figures at all, does it? I submit that these are "typical" Mosley figures
since most all of the antennas use the same trap and element configurations.
Here are the measurements for the KT34XA:
14.025 4.0 dBd
14.100 4.0
14.175 4.0
14.250 3.5
14.325 -2.5
21.025 6.0
21.125 4.5
21.225 1.5
21.325 0
21.425 -1.5
28.050 4.0
28.250 5.0
28.450 5.0
28.650 5.0
28.850 3.5
These are reproduceable results that have been confirmed with other
similar tests.
Before you get too excited, as of right now we will be presenting this
information at the DX Convention in Visalia and the Antenna Forum at Dayton.
The information is NOT available until then (we've got a couple more antennas
to test and then we need to finish the paper) so don't ask. It will be
available when it's done.
73, Steve K7LXC
TOWER TECH -- professional tower supplies and services for amateurs
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