[TowerTalk] Mosley/Antenna Testing (Was stepir vs c31xr)

[Bob Schreibmaier]

 >In a message dated 5/11/2007 11:11:44 A.M. Pacific Daylight Time,
 >towertalk-request at contesting.com writes:
 >
 >>  I will put my mosley ta-33 classic againt the 3 el ir or c31  force 
 >12 any
 >day and come up big in many ways,here they are: #1 the mosley 33 
 >classic is
 >650.00 shipped,my antenna get the same signal reports as the 3 el 
 >steppir
 >every time,and maybe the c31xr has a small margin of gain over both 
 >the IR and
 >mosley just because of it's much larger boom and more elements.now 
 >here you
 >have two antennas which preform equally,the difference is the stepp 
ir >cost
 >1700.00 thats 1100.00 more than the mosley,by the way my mosley is 
 >around 30
 >year old in the air.Still working like new.Had to change the coax a 
 >few times
 >and clean the traps which were really clean anyway.so you make the 
 >decision own
 >an antenna that does not require a tuner in line but will  definatley 
 >have
 >service issues in 5-10 years(How much is a motor?)or a mosley  you put 
 >up and
 >forget its there for 30+ years and save the 1100.00 towards a  new amp 
 >or
 >vacation.I rest my case..
 >
 >    But not very convincingly.
 >
 >    According to our yagi comparison report, here are  the published
 >REPEATABLE gain results of the C3 and the TA-33:
 >
 >                20M    15M    10M
 >C3           3.3        4.3    2.7
 >TA-33      1.2        2.3    1.3
 >
 >    At least this Mosley had gain, albeit not much;  the other Mosley 
 >PRO
 >antennas we tested had NEGATIVE gain on some bands.
 >
 >Cheers,
 >Steve      K7LXC
 >Champion Radio Products
 >Cell: 206-890-4188

Judging by the price quoted in the original post,
I suspect the antenna in question is a CL-33,
rather than a TA-33.  Interesting antenna.
Very different from every other 3-element
tribander I've ever used.  Driven element is
closer to the reflector than to the director.
When set up for CW, the driven element is longer
than the reflector.

In any case, W3MF and I got to use a borrowed
CL-33 in the 2005 ARRL DX Phone contest (thanks,
George!) when an ice storm took out the 4-element
quad.  We came in sixth place, multi-single.
Never did that well before, haven't done that
well since.  Yes, I realize this doesn't prove
anything about gain.  However, it shows that
the antenna system was pretty competitive.

Regarding TA-33 performance shown in the yagi
test report, I initially took the gain figures
as "gospel," until I looked at the SWR curves
in the back of the report.  The SWR curve, in
particular the 10-meter curve, should have set
off warning sirens in someone's head!  Clearly,
there was a problem with the TA-33 under test.
Given that it is a trap antenna for 10-15-20
meters, if there is a problem on 10 meters,
there is probably a problem on the other bands,
too.  So, I would take the TA-33 test results
with a grain of salt!

Your mileage may vary, of course.

73,
Bob
K3PH

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| Bob Schreibmaier K3PH | E-mail: k3ph at ptd.net |
| Kresgeville, PA 18333 | http://www.dxis.org  |
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