And the dipole wire (especially the ends) needs to be away from branches, shrubs ,etc.
John KK9A -----Original Message----- From: Don Wilhelm [mailto:[email protected]] Sent: Saturday, March 09, 2019 11:07 PM To: Peter Dougherty; [email protected]; [email protected] Subject: Re: [Elecraft] 80m KPA1500 High reflected power problems Peter, If your antenna end insulators are covered with ice and snow, it is entirely possible that the ice/snow covering will not show conductivity with low power, but will become conductive at high power. That will make whatever material you are using to support the antenna ends a part of the antenna radiator - effectively lengthening the antenna. Shake the snow and ice from the end insulators and/or use longer end insulators and there is a good chance your problem will go away. 73, Don W3FPR On 3/9/2019 10:17 PM, Peter Dougherty wrote: > John, I know there were some issues with my old tube amp, but it did load > enough to get me 275-odd DXCC entities with 1500W on 80 CW. The KPA has > never been used in the past on 80 since I was having antenna trouble (one > end was down all winter and it just got fixed today). > > Everything's snow covered out the back so I don't want to play around at the > coax switch at the moment. I'll try bypassing the switch when it's a bit > warmer and the snow is gone. > > Of note, last year with the weird SWR, the "old antenna" (same physical > space and height, just all different materials) was cut to 3750 and I used a > tuner for the bottom end. I found the tuner kept giving me "unable to find a > match" when I tried tuning with high power from my tube amp. I figured > replacing every factor in that chain would fix the issue; the only thing > that's the same is the antenna switch and the physical orientation of the > wires themselves. New amp, new coax, new balun, new wire, insulators and > even the support ropes were changed out. > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
