[Top] [All Lists]

Re: [TowerTalk] 3000' feedline...can I make it work?

To: "Jim Lux" <>, "Paul" <>,<>
Subject: Re: [TowerTalk] 3000' feedline...can I make it work?
From: "Tom Rauch" <>
Reply-to: Tom Rauch <>
Date: Sun, 2 May 2004 17:55:05 -0400
List-post: <>
I assume this is like typical drop wire for secondary power
feeds or LV drops that "self supports". That type of wire
has almost a straight lay in the direction of the conductor.
Current flow in a wire with minor twisting like that is just
in parallel with the wire direction and not from strand to

Current primarily flows on the outside edges of each stand,
not in the core or even on the inside areas of each strand
unless the stand diameter is comparable to skin depth.

Of course if the stranding is woven or twisted at a pretty
good pitch it becomes a problem, but I don't think that is
the case with large diameter semi-rigid wires. The only
thing that will make a substantial difference is large
diameter stranding causes a surface with gaps or valleys
between stands where little or no current flows, reducing
current carrying surface area (or increasing current density
in the outher areas of each strand that do carry current).

If it were my installation, I'd probably just install a few
hundred feet and measure loss. I doubt it will be all that
bad, but almost certainly it will be a bit worse than solid
copper. Hey, who cares if the loss doubles or quadruples if
it is almost zero to start with?

73 Tom


See:  for "Self Supporting Towers", "Wireless Weather 
Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any questions 
and ask for Sherman, W2FLA.

TowerTalk mailing list

<Prev in Thread] Current Thread [Next in Thread>