I helped a friend put up a 4 element 40 M KLM. I am sure that the 1 element is
just the driven element of that antenna. We did not have any problems with the
elements and there wasn't a truss necessary. It made it through several high
wind situations before the "weak" boom broke in half. (I think this was the
weak point of those antennas but should be of no concern for you. I completely
disagree with Jim about the CC XM 240. I have had that antenna up for a number
of years and although theoretically you might improve the XM240 with a
modification of the coils, the antenna is almost magic the way it works. There
is a problem with the coils and that is they are very touchy. I mine has been
through a number of storms in the last 15 years and near lightning strikes will
vaporize those coils. On two occasions I have had to buy new coils and replace
the old ones.
Bill W5VX
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Jim
Thomson
Sent: Thursday, January 28, 2016 9:32 AM
To: towertalk@contesting.com
Subject: [TowerTalk] Klm 40m-1
Date: Thu, 28 Jan 2016 14:11:21 +0000 (UTC)
From: Rod Greene <w7zrc@yahoo.com>
To: Arnie Pfingst <arnie123@hotmail.com>, "towertalk@contesting.com"
<towertalk@contesting.com>
Subject: Re: [TowerTalk] Klm 40m-1
Arnie,
I have one of the old KLM 40m-1 antennas and have used it for years. So far it
has served me well. They do not normally need a truss support. I don't know
what the wind specs are for your area of the country, but for the northwest
where I am located, no truss is needed, nor called for in the documentation.
I don't think the antenna is anything to "write home about" but it is a very
good antenna for a shortened 40. And it handles and turns easily on a tower. I
have no idea how it would compare to a CushCraft.
73, Rod/w7zrc
## My problem with the CC 40m ants..like their XM-240 is... they use like 68
turns of 12 ga magnet wire, wound butt tight on a 3/4 inch fiberglass form.
Loss in EACH coil is aprx 8.23 ohms. Q is like aprx 81. Any loading
scheme would be better than this..and easily fixable. 3/16 or 1/4 inch al
or cu tubing would be ideal.
## The LL rods used on the klm-40 could also be easily replaced with hb
tubing coils. Then you would have a loss of way under 1 ohm..and a Q of 750
1300 on either the klm or the CC ant.
## a simple dacron truss would ensure minimal sag with any snow or ice load.
Just make sure any truss is high enough above the 40m ele.
Jim VE7RF
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