Installing dummy elements out as far as I could reach was what I was
going to try first but dont know whether the would be far enough out
to do the trick. Yesterday I looked to see where the nearest element
is and it is probably out of reach. I may try tuning the thing and if
no luck put up another tower (temporarily or not) 30 feet to Northwest
of it, rotate the antenna to extend the boom on either end, and then
(if permanent) take a section off the new tower and put up an H frame
of 10m antennas fixed on Europe using both towers.
Not sure I even want to know the real impact of this resonance on the
pattern of the 40. I can say that I haven't had the "feeling" that
the 40m antenna has worked as well as it did a few years ago.
Unfortunately, about 75% of the time the 20 needs to be pointed in a
direction that makes it the worst.
Thanks to you and others for the thoughtful suggestions. I'll report
what I end up eventually doing.
Stan, K5GO
Sent from Stan's IPhone
On Oct 24, 2010, at 7:33 AM, TexasRF@aol.com wrote:
> Since the 20m elements are insulated, would installing a ground
> strap to an
> element near the boom detune things enough to work?
>
> Could an additional "dummy" element or elements be added
> temporarily for
> detuning?
>
> Or, Install back to back gamma rods on the boom (near the mast) to
> create a
> resonant circuit? Sort of like the technique to detune towers on lower
> bands.
>
> Probably too much work to set up the 20m boom as a 75m dipole like
> the old
> TH6 loaded boom trick from years ago.
>
> Or, finally, a big old autotuner for the 40m beam, heh-heh!
>
> 73,
> Gerald K5GW
>
>
>
>
>
>
>
>
>
>
> In a message dated 10/24/2010 1:26:47 A.M. Central Daylight Time,
> k5go@cox.net writes:
>
> Thanks for all the responses! Still looking for something I can do,
> even temporarily, without taking it down.
>
> Thanks...Stan, K5GO
>
> Sent from Stan's IPhone
>
>
>
> On Oct 23, 2010, at 8:04 PM, Stan Stockton <k5go@cox.net> wrote:
>
>> Anyone by chance have an easier to accomplish idea other than one I
>> remember being suggested to someone else with a similar problem -
>> fishing a wire through a hole near the center of the boom and
>> letting
>> it hang out the end. I can watch the SWR on my 40 meter antenna go
>> from 1.2/1 to 2.0/1 just by turning the rotatable 40m Yagi or the
>> 20m
>> Yagi which is about 175 feet away and 65 feet lower. Boom is 65
>> feet
>> and elements are insulated.
>>
>> Lesson learned on boom lengths...
>>
>> I would prefer to fix it with the least amount of work. I can
>> probably do the wire thing on one side but not the other due to an
>> weight-balance obstruction. Hate to have about 15 feet of wire
>> hanging out if the back of the boom.
>>
>> Thanks...Stan, K5GO
>>
>> Sent from Stan's IPhone
>>
>>
>> _______________________________________________
>>
>>
>>
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