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 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
