[TowerTalk] <LONG> New Info: Yagi Interaction on 15m: KT34XA and XM240

[K7LXC@aol.com]

In a message dated 10/26/00 3:21:08 PM Pacific Daylight Time, 
jmaass@columbus.rr.com writes:

> The SWR curves at the point the feedline entered the shack were
>  very good. The curves at the transmitter were not.
>  
>  So, I started the process of eliminating from the signal path the
>  two wattmeters, the amplifier, the RCS8V remote switch, the
>  (bypassed) N4XM XMatch antenna tuner, and each of the
>  interconnecting cables.
>  
>  I suspected the Ameritron RCS8V remote antenna switch that I
>  use in the shack to select antennas, but removing it made no
>  difference at all.
>  
>  To make a medium-length story shorter, the problem was the
>  XMatch tuner. Although it was in "Direct" (that is, bypassed),
>  it raised the minimum measured SWR at the low end of 15m
>  (using either measure) from around 1.2:1 to 1.5:1 or 1.6:1!

    Congratulations - you've fallen into the same trap as many others have. 
The vast majority of 'antenna problems' I've run into involved SOMETHING ELSE 
in the shack; i.e. bad switch, bad jumper, etc. 

    Bottom line: When you're testing an antenna, eliminate everything and 
plug the analyzer directly into the antenna feedline. 

Cheers,   Steve    K7LXC
Tower Tech 

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