On Mon, 22 Jun 1998 18:49:54 +0800 "Edward Soriano, M.D., DU1OZ, KB3CNO"
<du1oz@writeme.com> writes:
>
>According to the book 50 mhz band have some characteristics of both HF
>and VHF. I will soon install a 6 meter beam ( a new band for me)and
>will
>need more or less a roll of 100 feet coax to the tower. I don't want
>to
>spend for a new line. I have a couple of used RG-8 coax cut into
>lenghts
>of 50 feet which I plan to use. I wonder how sensitive is the band to
>cable losses? Will there be a big difference in using old and new
>lines?
It depends on how bad the old line is. You can test the old line
by connecting an antenna analyzer or Bird wattmeter to one end
and measuring the swr with the other end open.
loss (dB) = 10 log [(swr+1)/(swr-1)]
If your antenna analyzer doesn't go up to 50 Mhz, measure the loss
at 30 Mhz, and multiply the dB value by 1.35 for an estimate
at 50 Mhz. A new 100' piece of RG-8 or RG-213 should have a loss of
1.35 dB at 50.1 Mhz. If your old line has a loss of 2.35 dB or
less, I would go ahead and use it. If you decide to get serious
about 6 meters, you can buy some better stuff later on.
Dave Hachadorian, K6LL
Yuma, AZ
K6LL@juno.com
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