[Towertalk] TH11 SWR Problem

[K7LXC@aol.com]

In a message dated 4/15/02 6:58:41 AM Pacific Daylight Time, DK2GZ@aol.com 
writes:

> The Problem:
>  
>  Sometimes the swr jumpes up from 1:1.2 to 1:3.
>  
>  He did exchange the entire coax from the shack up to the antenna in one 
> piece.
>  No difference!
>  
>  Then he disconnect the balun.
>  No difference.
>  
>  He checked the entire antenna for poor connection, but canīt find any
>  poor connection.
>  
>  The problem getting stronger on the higher bands, 20 meter is quiet fair,
>  but on 17,15,12 und 10 the swr jumps up and down, also with low power
>  100 watt. The effect is increasing with the frequency.
>  
>  He checked the antenna also with his swr analyzer(MFJ) without any power
>  and got the same swr-jumping.

    Assuming everything you checked is really okay, the only thing left is 
the traps. Perhaps you have a loose connection in one? Insects like spiders 
have been known to build nests in the traps so it sounds like you need to 
take them apart to check them. These antennas have generally been quite 
reliable so I haven't really seen this problem before except for the insect 
invasion type. 

Cheers,
Steve     K7LXC
TOWER TECH