Reply to the message of Friday July 10, 1998 09:49 -0400
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>The early charts had gross errors in attenuation for these line types,
>I have no idea if the later ones do. The error was in the direction of
>much to little loss.
Tom, I have the 1996 edition ARRL Antenna Handbook. It shows open
wire types as having much lower loss than hardline. Starting with which
year's edition were the loss charts corrected?
>Remember MOST 450 ohm ladder lines are not 450 ohm at all. Some 450
>lines are as far off as the upper 300 ohm range.
I had no idea it was that far off. I wonder why they call it 450 Ohm?
>TV twinlead is pretty
>good for dry weather impedance, but ALL of these unshielded lines have
>high wet weather loss at VHF and above. Mounting is also critical, as
>is current balance and physical balance to surrounding conductors.
Right. Twisting it and installing it inside pvc seemed to be a reasonable
amount of work to get a super-low loss feedline, but now that the chart is
in question, I'm not so sure. I guess if it was a really good thing,
everybody would already be doing it.
Mark, N1LO
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