If he hung some capacitance hats off the top of the tower, would that work.
Maybe something to try.
Mark N1UK
----- Original Message -----
From: "David Gilbert" <xdavid@cis-broadband.com>
To: <towertalk@contesting.com>
Sent: Tuesday, 05 October, 2010 3:59 PM
Subject: Re: [TowerTalk] Tower Detuning
>
>
> Well, as Jim pointed out (and as I should have) the operating frequency
> was much higher (12 to 15 times higher), and we used three clamp-ons
> instead of one. To a first order approximation (I didn't look at the
> material curves)that's 40 times the choking action of the single
> identical clamp at 1.8 MHz. We would have used more clamp-ons except
> that it was already getting kind of expensive and it made sense to see
> if there was any improvement at all before spending money on more of
> them. As it turned out, the three clamp-ons for each guy worked well
> enough that K9RX was satisfied with that.
>
> 73,
> Dave AB7E
>
>
>
>
>
> On 10/5/2010 11:33 AM, Michael Baker wrote:
>> OK, well that raises another question.
>> If a clamp on bead works with a single cable and a single turn, why
>> doesn't
>> it work with a Tower? Granted, on zig zag reinforcing on the tower, they
>> would also have to get a bead to break up the path but why not work? If I
>> can clamp on one each to each leg of an overhead power source to keep RF
>> off
>> the service entrance, why not a tower leg?
>> It is still a single turn?
>>
>> Section (cut in half with a diamond wheel) Mix 31 toroids and band them
>> around the leg. If 5 to 7 work as chokes for coax it should work for the
>> leg.
>>
>> What have I missed? (OK< yes, the guys also must be done as well AND
>> all
>> cables descending down the tower.
>>
>> Just curious.
>>
>> Michael Baker K7DD
>> k7dd@cox.net
>>
>>
>> -----Original Message-----
>> From: towertalk-bounces@contesting.com
>> [mailto:towertalk-bounces@contesting.com] On Behalf Of David Gilbert
>> Sent: Tuesday, October 05, 2010 10:11 AM
>> To: towertalk@contesting.com
>> Subject: Re: [TowerTalk] Tower Detuning
>>
>>
>> I agree ... one turn through a core is insufficient on 160m.
>>
>> Using clamp-ons can be useful in other semi-similar situations, though.
>> A couple of years ago afriend of mine, K9RX, was having significant
>> detuning issues with his 3-stack of KT34XA's. He could see the effect
>> on SWR (and presumably pattern) on either 15m or 10m (I don't remember
>> which band .. maybe both) as he rotated the stack. He was convinced he
>> was getting interaction with the top sections of each guy even though he
>> had them split with insulators per the usual recommended lengths. We
>> put three Mix-31 clamp-ons from DX Engineering on the top section of the
>> guys out as far as I could reach from the tower at each level and the
>> situation dramatically improved.
>>
>> 73,
>> Dave AB7E
>>
>>
>>
>>
>> On 10/5/2010 9:28 AM, Jim Brown wrote:
>>> On 10/4/2010 3:00 PM, Michael Baker wrote:
>>>> How about using the Giant Clamp on Beads made my Fair-Rite?
>>>> Clamp one or more on each leg and the descending cables.
>>> Sorry, that will NOT work -- the impedance of a single turn through
>>> these parts are FAR too small to have any effect on 160M.
>>>
>>> 73, Jim Brown K9YC
>>> _________________
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