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Re: Topband: Have a pproblem with my 4 square on 160 mtrs

To: WD8PKF@awcmail.com, topband@contesting.com
Subject: Re: Topband: Have a pproblem with my 4 square on 160 mtrs
From: kl7ra@ptialaska.net
Date: Fri, 4 Dec 2009 09:51:52 -0900 (AKST)
List-post: <topband@contesting.com">mailto:topband@contesting.com>
>Can anyone give me some idea where to start with this problem
>and some ideas on a fix before the snows come?

Hi Alan

One troubleshooting technique is find something that would
cause this problem if you were to do it on purpose.

Since this is a hybrid I would guess a port not terminated into
50 ohms, (75) would cause the failure mode you see.

Since it is caused by transmitting a lot of power and the array
stays broke for awhile I would assume one of the antennas has been
removed from the hybrid. Sounds like a bad connection or connector
burned with a carbon trace to ground.

You might be able to find it by adding a second dummy load to each
antenna port in turn as you run power and see if the SWR stays stable
for one which would indicate it has the failure.

Beware that the second load needs to handle the power. I blew out
a load using this troubleshooting technique and it set me back
"hours".

73 Rich KL7RA

p.s. I also have this array on a dedicated tower for 80 meters and
it works great.


_______________________________________________
160 meters is a serious band, it should be treated with respect. - TF4M

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