[TowerTalk] Mosley Beam Questions
K7LXC@aol.com
K7LXC@aol.com
Tue, 5 Dec 2000 12:58:56 EST
In a message dated 12/5/00 7:12:25 AM Pacific Standard Time,
emoore@windemullerelectric.com writes:
> I'm looking into upgrading my station in the spring and realizing Mosley's
> long lead time, I will order it know to have in plenty of time for a spring
> installation. I currently use a TH-3JR. and really have to be careful with
> my power output. I have a SB-220 amplifier.
>
> I am undecided between the TA-53-M and the CL-33-M-WARC.
>
> My questions to the group are:
>
> 1. Which is more important, forward gain, or front to back ratio?
What kind of operating are you planning? Contestors typically want more
gain and would be interested in working stations off the back whereas DX'ers
are typically interested in F/B since they're usually trying to hear thru a
pileup and want as much other signal rejection as possible.
>
> 2. Should I sacrifice gain on 17M and 12M for better front to back ratio?
>
ANYTHING you do to a Yagi antenna is a compromise. Your design parameters
include forward gain, F/B, bandwidth, SWR, feedpoint impedance, etc. so if
you change one thing, it affects everything else. Mosley antennas are not
known for their clean (or discernible) patterns so in this case it probably
doesn't make any difference.
> 3. Is there another 5 band beam I should consider other than Mosley?
Uh...ANY other antenna IMO. Pete suggested an LPDA; they're becoming
pretty popular. You didn't mention how big of an antenna you'd consider;
another choice would be a TH11 as is the Cushcraft X-7 (smaller than the
X-9). For the best bang-per-buck (and small size since your antennas of
choice have 14' and 15' booms), I'd go with the Force 12 C-3 in a NY minute.
It'll run circles around most Mosleys (even the PRO antennas) and the
*compromise* performance on 12 and 17M means that it still works reasonably
well on those bands.
>
> 4. Any other thoughts.
Generally gain is a function of boomlength so you need a bigger boom to
realize much in the way of performance gain over a 15-foot or so long boom.
You won't see hardly any difference between the little Mosleys and the TH3;
the only thing you get is some WARC band coverage - hardly worth the work and
investment IMO.
>
> 5. I am aware in the long lead time and are not concerned, as I am also
> familiar with the Mosley quality.
>
Are you familiar with their performance? Try our tribander comparison
report for an on-the-air analysis of a dozen tribanders including 3 Mosleys.
Available from Champion Radio Products.
> I will be mounting this at around 35' and can accommodate around 15sq. ft.
I
> should minimize the number of elements to keep the XYL happy, but are open
> to any suggestions!
>
If you've got that much capacity, skip the little antennas and go
directly to the TH11, LPDA or something similar. Even a CC stack of an A-3
w/40M kit and a A-3WS with 30M kit will give you better performance than the
Mosleys and total 40-10M coverage.
Cheers & GL, Steve K7LXC
www.championradio.com
Tower Tech
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