[TenTec] TWINCOM feedline ?????????????

[geraldj@isunet.net (Dr. Gerald N. Johnson, electrical engineer)]

The wider the space the more the feed line radiates. The thin spacers of
the TWINWIRE compared to the plastic ladder lines means its less
affected by wind, and maybe by ice. I've used flat lines for decades but
found when hanging 50 or 60 feet from the antenna to the ground anchor
(I try to keep them under tension) that they have too effective an
airfoil and a bit of normal Iowa wind will break them. I've used 1"
spaced #18 copperweld with plastic spacers more recently with better
results except when there's a breeze and its coated with ice it breaks
into several pieces.

There is no advantage to 700 ohms over 450 or 600 ohms, but there is
advantage at the tuner end for any of those impedances over coax when
the antenna is a full wave long and the feed line is an odd multiple of
a quarter wave long.

73, Jerry, K0CQ

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Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.