[Elecraft] K3 KAT3 Antenna Tuner Tutorial

[Geoffrey Mackenzie-Kennedy]

Dale, I suspect that in Windy's case moisture could be entering via tiny 
holes drilled in the dielectric by windblown sand or dust. Unfortunately I 
cannot offer any practical solution to prevent this happening, because I do 
not use window line.

4 wire open wire feeder behaves like a lovesick octopus unless kept under 
tension.  A very useful type of low cost feeder for long low loss horizontal 
runs at HF and VHF though.

73,
Geoff
GM4ESD


Dale Putnam wrote on Thursday, October 22, 2009 1:01 PM

Geoff has touched on what may be happening. I've seen this on my systems 
here too... and the issue comes down to the material, in this case mud or 
water and dust... collecting on the feeder, then as the moisture drys away, 
the change in transmission line characteristics also change. There are a 
whole page of math equations and figures that prove this, but suffice it to 
say for now, that open wire, doesn't have this issue... it has others... 
more physical, like how to keep it spaced and installed correctly.
  Retuning isn't a real problem, it is pretty much just adjusting for what 
the moisture is changing. However... be watchful for the moisture changes to 
not go away completely.... then go look for where the moisture isn't leaving 
and find an opening in the insulation, and repair it, before the feedline 
becomes damaged too much by the moisture invasion.
 Still beats coax for losses.

--... ...-- Dale - WC7S in Wy