Posted by
Jim Brown-10 on
Dec 17, 2018; 7:58pm
URL: http://elecraft.85.s1.nabble.com/wire-for-random-wire-antenna-using-kx3-tp7647146p7647156.html
On 12/17/2018 6:45 AM, Don Wilhelm wrote:
> However, if you are using the speaker wire as a transmission line, it
> has relatively high loss characteristics
Compared to what? So-called speaker wire (which is really lousy for
speakers because it should be twisted pair to minimize RFI) has Zo in
the range of 75-100 ohms. Unless it's wet, virtually all the loss in
transmission lines below about 100 MHz is due to wire resistance, not
dielectric loss. There is, of course, additional loss due to any
mismatch that may be present, but that still comes down to loss in the
resistance of the line. While I haven't measured any zip cord, I've
measured a lot of closely spaced parallel wire transmission line made
from THHN, enameled copper, and Teflon insulated #12 silver-coated
copper. In order of loss at dB/100 ft at 10 MHz from low to high, the
Teflon #12 is lowest at 0.94dB, then RG400 at 1.22 dB (about the same as
RG58), then #12 THHN at 1.34 dB. #12 or #10 enameled copper had the
greatest loss, 2.4 dB/100 ft.
73, Jim K9YC
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