> If I have to use your antenna, then my move would be to replace the 250' > of75 ohm coax with 250' of 450 ohm ladder line, check the fan dipole legs > are exactly the same to provide a balanced load.
You're on target about loss in the feedline, but ladder line is not a good move here.David has resonant dipoles, so they are a pretty good match to 50 or 75 ohm cable. Folks think QRP, so they think small coax, But when the line is as long as these are, the loss certainly gets out of hand unless it's bigger coax. If I were to make ANY change in the feedline, it would be to a decent RG8 or RG11. I would also look at ways to reduce the length of the line by finding a shorter route to the shack. You don't need expensive coax -- Davis 213 is about as good as it gets for the HF bands, and it's fairly inexpensive. Window line is NOT the cure for all ills -- it is as lossy as small coax when it gets wet, and there's some loss (and cost) in any impedance transforming balun. Further, most real antennas are unbalanced by their surroundings, so they need a good ferrite common mode choke at the feedpoint whether they're fed by coax or parallel wire line. 73, Jim Brown K9YC ______________________________________________________________ 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
