[TowerTalk] SWR Problem Balun or lightning protection?

[Jorge Diez CX6VM]

Hi Tony,

I have this M2 20M5 antenna. Before cqww ssb I installed high power band
pass filters for a Multi Single and experimented problems in the SWR of this
antenna.
 
FREQ.		WITHOUT FILTER		WITH FILTER
14025		1.37                        1.80
14300        1.46                        2.51

Filters provider told me to do some test, and seems SWR varying if I add
some lengths of coax (jumpers) inside the shack. So seems the balun is bad?

Same as you, using balun provided with this antenna from M2.

73,
Jorge
CX6VM

-----Mensaje original-----
De: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] En nombre de Tony
Enviado el: miércoles, 21 de diciembre de 2011 07:41 a.m.
Para: towertalk at contesting.com
Asunto: Re: [TowerTalk] SWR Problem Balun or lightning protection?

On 12/20/2011 10:22 PM, Gene Fuller wrote:
> Hi Tony - Can you find out what's in the balun? Possibly a capacitor that
is changing value as it heats up. Gene / W2LU

Hi Gene - it's an M2 3KW 1:1 balun. I'll give them a call tomorrow. 
Thanks for the suggestion.

Tony
>
> ----- Original Message -----
> From: "Tony"<dxdx at optonline.net>
> To:<towertalk at contesting.com>
> Sent: Tuesday, December 20, 2011 7:41 PM
> Subject: [TowerTalk] SWR Problem Balun or lightning protection?
>
>
>> All,
>>
>> The SWR on my 5 element mono band Yagi rises after I key down for a few
>> minutes. The 2:1 SWR bandwidth behaves normally until the problem
>> occurs. The SWR goes to normal after waiting a few minutes, but then the
>> problem starts again after I key down for a while.
>>
>> The only things inline are the lightning protection (polyphaser) and the
>> balun which is mounted at the antenna. The antenna is made by M2 and it
>> uses an M2 balun.
>>
>> I'm going to bypass the lightning protection tomorrow as a process of
>> elimination, but I was wondering if the problem is more likely to be
>> caused by the balun?
>>
>> Thanks,
>>
>> Tony
>> _______________________________________________
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>>
>>
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