[TowerTalk] Klm 40m-1

[Joseph Feustle]

Before moving to my current location twenty-eight years ago, I put two 
KLM-40-m dipoles on a sixteen-foot boom, built a feed-point match like 
the Hy-Gain (?) 2-el forty of the time, and put it 10 feet below my 
tribander at 45 feet. Kicked butt. No room for it here but I do survive 
with a Hy-Tower. The 2-el forty now resides in my garage along with a 
large Force-12 multi-el. Next time I move..., but do they work under ground?

Ah, point and shoot on 40 was fun.

73,
Joe Feustle, N8JF

On 1/28/2016 1:27 PM, Don W7WLL wrote:
> Has been interesting to read the posts on this old antenna and the 
> various comments on how well or not they have worked for those who had 
> or have one.
>
> I also have one. It is assembled, setting on some sawhorses out by the 
> tower and ready for remount with a TH7DX and A3WS on my HG-70HD tower. 
> My initial plan, after I get the rotator issue I have solved, is to 
> lower the A3WS a couple of feet and put the dipole at mast top, above 
> the A3WS.
>
> Mine must be pre-40M-1 as all the literature that came with it just 
> calls it a KLM 7.2-1 DIPOLE ANTENNA.
>
> When previously mounted in Portland on a TriEx WT-51, I never used a 
> truss nor do the instructions call for any. Even with the higher winds 
> we see here on the OR coast where we moved some years back, after 
> considering all the other two beams have gone through, I don't plan to 
> truss it (the TH7DX of course is trussed).
>
> This is an interesting rotatable dipole design but does have a fairly 
> limited bandwidth. My recollection, for the settings I had, was that 
> it was close to 1:1 at the desired 7125 freq setting and ramped up to 
> about 2:1 at 7050 and 7200. Without a tuner it performed OK over the 
> whole band but at a lot higher SWR. It didn't perform any better than 
> a regular dipole except for the ability to rotate and maximize signals.
>
> I don't know what the later 40M-1 manuals said, but mine even 
> discusses using the dipole vertically off a 20M or other beam, going 
> to far as to state that if mounted vertically with 'proper' spacing 
> from the tower that one might even get a little gain and F/B!!!  Never 
> heard of anyone trying it and I remain dubious.
>
> KLM also claimed that because of the 'specially designed linear 
> loading' that it should not cause any interaction with a 20M beam and 
> could even be mounted horizontally on its boom!!! I never heard of 
> anyone doing this either, but I have considered mounting it to the 
> mast below the TH7DX parallel with the elements (not the boom) just to 
> see what the results would be !!
>
> The instructions also give some suggestions for other configured uses 
> of the element halves.
>
> Along with my build and install instructions is a page which tells how 
> to convert another 7.2-1 dipole and turn the two into a 2-el 40M beam. 
> The sheet also provides instructions for getting the antenna to 
> operate in the 8.1 to 8.7 MHz area (say what????)
>
> After KLM moved from CA to WA I assume that changed the nomenclature 
> to 40M-1 (?).  I know they offered conversion kits in '96 (I have a 
> KLM retail price list) at roughly $300/element to create a 2, 3 or 4 
> el 40M beam using the original dipole. I also have a copy of a 
> dimensions sheet (with VSWR charts) and a list of parts for creating a 
> 2 el. I don't know if was produced by KLM, but suspect so.
>
> I looked for another KLM 40M rotatable dipole quite a while back, with 
> the thought then of building a 2-el, but never found one and dropped 
> the effort from my bucket list.
>
> So, has anyone with one of these tried the 'different' mounting 
> methods KLM suggests and if so how did it turn out???
>
> Don W7WLL
>
>
>
> -----Original Message----- From: Arnie Pfingst
> Sent: Wednesday, January 27, 2016 8:37 AM
> To: towertalk at contesting.com
> Subject: [TowerTalk] Klm 40m-1
>
>
>
> I have a chance to buy a klm 40m1 rotatable dipole. The fella said its 
> on the ground. He said he "refurbished it" he has some paperwork for 
> it and a 5kw balun with it. My questions are, does this antenna need a 
> truss support and how do I put one on, was this antenna really 
> anything to write home about. How does it compare to say... the 
> cushcraft d40?Arnie
> Sent via the Samsung Galaxy S®6 active, an AT&T 4G LTE smartphone
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