[TowerTalk] KLM-40M4

[Kurt Andress]

Dave,
Having one of these is a career move, if you get regular 50 Mph plus winds.
If the Lexan boom to element mounts don't break (which they regularly do),
the linear loading shorting strap connections will shake themselves LOOSE
(notice how nicely I've spelled it). This transforms your antenna into a
very effective broadband spark gap transmitter. 
I vividly remember spending 2 hours, at 100', at midnight, in a stiff
breeze, on Saturday night in a CQWW Contest trying to tighten all of the
shorting strap connections on one of these things. It was visibly arcing
and hammering all of the other bands at the Multi/Multi station.
Fortunately, several months later the Lexan pieces broke and the 'beast"
got completely rebuilt. It lasted 2 more years and finally had its material
converted into WARC band antennas, without any of the linear loading or
plastic parts. 

Another one, here in N. Nevada, at 70' lasted 2-3 years and then got sold
for really cheap, because the owner swore not to ever repeat the headache.

The problem is the same, whether it's 2, 3, or 4, elements. These things
are good to approx. 70 Mph by my software. This doesn't account for the
shorting strap LOOSENING problems, which I figure occur at lower wind
speeds.

If you live in an area that does not get frequent wind, and never gets high
winds, you will find your rebuild frequency tolerable. Still, a career
move, in my opinion. I could have bought the really cheap 40M4, but didn't!

Otherwise, there are better solutions for 40 meter yagis. The multitudes
swear by the Cushcraft 402, which you should be able to get for close to
the same $500.
If you are interested in, better performing designs, send me a private
e-mail.
73, Kurt

YagiStress - The Ultimate Mechanical Design Software for Yagi's
Visit - http://freeyellow.com/members3/yagistress

----------
> From: David Jordan <wa3gin@erols.com>
> To: towertalk@contesting.com
> Subject: [TowerTalk] KLM-40M4
> Date: Wednesday, July 01, 1998 6:43 PM
> 
> 
> 
> 
> Folks,
> 
> Thinking about buying subject antenna. New in the box for $500. Would
> appreciate any
> comments regarding performance (or comparisons), reliability, etc. It
> will be mounted on a
> crank-up tower (CT-100) so it won't be up in the air during bad weather
> if I can remember to crank it down 50ft.
> 
> thanks,
> dave

YagiStress - The Ultimate Mechanical Design Software for Yagi's
Visit - http://freeyellow.com/members3/yagistress

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