[Elecraft] Strange SWR change on 20 at

[Nr4c]

What's the antenna impedance before the ATU is activated?  You may be heating up the BALUN due to big mis-match. 

Sent from my iPhone
...nr4c. bill


> On May 13, 2017, at 12:07 PM, Terry Brown <n7tb at comcast.net> wrote:
> 
> I recently started using my horizontal loop that is about a full wavelength
> on 80, for 20 meters.  I took down my yagi as we are moving; drat!  My
> Horizontal Loop is at 40 ft.  height and fed with 450 window line into a 4:1
> voltage balun with about 15 ft. of coax to rig.  
> 
> 
> 
> I am running 100 watts through my KXPA100.  I tune a frequency in the CW
> portion of 20 to about 1.2 :1 and start sending CQ.  After about 3 to 4  3x3
> CQ's,, the SWR goes off the charts and power drops to zero.   I can retune
> the antenna and the process repeats itself.  20 meters is the only band
> affected.
> 
> 
> 
> I am wondering if I am having RF problems in that part of the 20 meter bands
> This only occurs on 20 meters.  The Amp is grounded, but the KX3 is not
> bonded to the Amp.
> 
> 
> 
> I would appreciate any advice.
> 
> 
> 
> Thanks and 73's,
> 
> 
> 
> Terry de N7TB
> 
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