> Well heck if LMR400 is .7dB/100ft I'm not so sure that its worth mucking > with finding adapters for it as if I end up having to put 2 adapters on > each end to get it to something I can use there goes most of my > advantage of stepping up from LMR400 to LMR600...
The loss in connectors or adaptors at HF or even up into VHF is virtually immeasurable, unless they are simply terrible. If the connectors are terrible you might have 0.05 dB loss. A common SO-239/PL259 junction has less than .02 dB loss at upper HF. I'd be more concerned with transmission line losses due to SWR on the transmission line and voltage breakdown of connectors in your application. Here are the peak voltages at the antenna base with only 100 watts applied at the antenna, and the losses in a feedline using 100 feet of LMR500: 160= 4800v (>100:1 SWR) 16 dB feedline loss 80 = 1000v (>100:1 SWR) 6 dB feedline loss 40 = 215v (5.4:1 SWR) .6 dB feedline loss 30 = 500v (26:1 SWR) 3 dB feedline loss 20 = 540v (29:1 SWR) 3.5 dB feedline loss 15 = 280v (9:1 SWR) 1.7 dB feedline loss Why would you worry about connectors when 100 feet of LMR500 would have losses like that? Put a tuner at the antenna base if you want to reduce losses. 73 Tom ______________________________________________________________ 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
