Hey Frank,
I have the same problem with my three elements yagi on 50 Mc/s
To high SWR when wet ( rain or fog ). A short end of coax serves as a cap to
adapt.
I should change that kind of tuning for sure.
The value change a lot when wet.
So have alook again to your refurbished traps.
Jos on4kj
----- Original Message -----
From: "Frank Davis" <fdavis@nf.sympatico.ca>
To: <towertalk@contesting.com>
Sent: Thursday, November 07, 2002 9:19 PM
Subject: [Towertalk] HI SWR during rain - EXP-14
> Last summer I completely refurbished my 20 year old Explorer 14.
> I cleaned the aluminium contact surfaces and took the traps apart
> and cleaned them and replaced all rusty screws etc.
> Recently after a particularly heavy rain and wind storm the SWR
> went up on 20 and 15 to about 3:1. 10M SWR no change. After
> a couple of days of drying in the wind the everything has returned
> to normal......
> I cranked the tower over and did a visual inspection and did have
> to reposition the inside end caps back over the ends of the driven
> element traps. They had vibrated out of place in the gusts. I
> couldn't see any other issues to deal with.
>
> Today it is raining and blowing again with a nice helping of wet snow
> mixed in. The SWR is up again on 20/15 and no change on 10m.
> I don't recall this happening in the past on this yagi and I wonder what
> is happening. The obvious answer is water in the traps.....but why
> didn;t this happen in the past before I took everything apart to refurbish
??
>
> Also would the water cause this to happen if it gets into the driven
> element traps only or would it happen if water is getting into the
> parasitic traps and not the DE traps?? There is no change in SWR
> on 10M ...there are no 10M traps in the DE ..... so I am assuming that
> the problem must be water in the 20/15 DE traps.
>
> Anyone with any ideas or comments.
>
> Frank VO1HP
>
>
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