A few years ago, I measured a length of plastic (some form of vinyl, I believe) insulated zip cord with the loss results below.
Impedance over the range 300 KHz - 30 MHz varied from 118 ohms to 124 ohms. Jack K8ZOA Frequency MHz Loss (dB)/100 ft 5 2.3 10 3.5 15 4.6 20 5.5 25 6.9 30 8.1 35 8.7 40 9.2 45 10.4 50 11.6 On 9/11/2011 8:20 AM, Bill W4ZV wrote: > Fred Townsend wrote: >> Rubber (parallel) lamp cord can be used as transmission line and it is >> cheap. Z0 runs 95 to 120 Ohms depending on insulation thickness. >> > True, but it has very high loss (especially at higher frequencies) and > should only be considered as a last resort. About 10 years ago ET3PMW was > attempting to get on the low bands and only had zip cord available for > transmission line. I thought it should work fine for 80 and 160. However, > on 80m running 100 watts he was barely detectible here using a 1200' > Beverage for receive. Once Paul got some good ladder line, his signal was > typically S8 on 80m and S6 on Topband, where he made several hundred QSOs > with North America even in summer QRN (June/July). > > There is a loss graph on page 2 below but I believe ET3PMW's losses were > much higher. Of course this could have been due to poor quality wire > available in Ethiopia. > > http://www.we0h.us/Amateur_Radio_stuff/Antenna/ZIP-Cord-Antenna/Zipcord-Antenna-7903031.pdf > > 73, Bill > > > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/What-your-mother-didn-t-tell-you-about-transmission-lines-tp6780383p6780644.html > Sent from the Elecraft mailing list archive at Nabble.com. > ______________________________________________________________ > 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 > ______________________________________________________________ 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
