I have a 425 foot run of "window line", specifically Wireman #554 down to my 160 antenna base. The "detuning" that is referred to is really a change in the dielectric: from PE to PE+water. That changes the loss (change = .5 dB at 1.830), but more particularly the velocity factor, which changes the electrical length and MOVES nodes and nulls. Here are the particulars from the line loss calculator in VK1OD's excellent collection of calculators at http://vk1od.net/calc/tl/tllc.php .
Transmission Line Wireman 554 Code W554 Data source Wireman / N7WS Frequency 1.830 MHz Length 425.000 ft Results Zo 360.01-j1.74 Ω Velocity Factor, VF -2 0.928, 1.161 Length 306.76 °, 0.852 λ, 129.540 m Line Loss (matched) 0.251 dB Transmission Line Wireman 554 wet Code W554w Data source N7WS Frequency 1.830 MHz Length 425.000 ft Results Zo 344.94+j3.02 Ω Velocity Factor, VF -2 0.887, 1.271 Length 320.94 °, 0.892 λ, 129.540 m Line Loss (matched) 0.780 dB 73, Guy. On Sun, Mar 11, 2012 at 12:16 AM, Jim Brown <[email protected]>wrote: > On 3/10/2012 9:05 PM, Gary Ferdinand wrote: > > The OWL does not suffer from the dreaded detuning in the rain nearly to > the extent of ladder line. > > Right. And while there is some change in the impedance, the primary > effect is dielectric loss due to moisture on the "solid" portions of the > window "frame." > > 73, Jim K9YC > > ______________________________________________________________ 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
