On 12/6/12 1:08 PM, Frank wrote:
Rick Karlquist wrote:
No. I originally had the shack 1000 feet from the low
band vertical. It's nice to have 0.1 dB loss over 1000 feet
of line on 160 meters. They don't really sell aluminum much
smaller than #4. The light weight is great for suspending
it. I have been extremely pleased with this line.
Sounds great.
You can buy 250 foot rolls of #17 aluminum electric fence wire. Costs
about $7 a roll. Good for wire antennas. Probably not all that good
for a 1000 foot run of lader line.
#17 will have somwhere between 4-16 times the resistance of #4. Every 6
gauges is half the diameter, so if skin depth is <<diameter it would be
4 times the resistance. If skin depth is a good fraction of diameter it
will go more as the cross sectional area, so more like 16 times.
Skin depth at 2 MHz in aluminum is 0.0023 inch or 58 microns.
AWG 4 is 0.204 inches
AWG 17 is 0.045 inches.. (20 skin depths)
so I'd go more for the 4 times the resistance....
So loss would be around 0.4 dB/1000 ft... (based on Rick's number)
Given the inexpensive nature of that wire, you could make quadroline (or
just double/triple/quadruple it up, like "bundled conductors" for HV
transmission lines) and get down to the 0.1 dB range at the cost of
(signficant) additional complexity.
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