[TowerTalk] Klm 40m-1

[Bill Parry]

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 at contesting.com] On Behalf Of Jim Thomson
Sent: Thursday, January 28, 2016 9:32 AM
To: towertalk at contesting.com
Subject: [TowerTalk] Klm 40m-1

Date: Thu, 28 Jan 2016 14:11:21 +0000 (UTC)
From: Rod Greene <w7zrc at yahoo.com>
To: Arnie Pfingst <arnie123 at hotmail.com>, "towertalk at contesting.com"
<towertalk at 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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