PVC tubing to stand off the line from the tower at the top, bottom and a few
places in between seems to work. 12" spacing should be sufficient for 600
Ohm open-wire, a bit less should suffice for ladder line, which will have
closer conductor spacing. I've used stainless steel screw-eyes threaded
into the PVC tubing, and spaced apart the same distance as the conductors in
the open wire, to let the line "slip" up and down a bit, rather than be held
rigidly in place, so the line can bob a bit in the wind, but never come
close to touching the tower.
(I've also used "nothing" to stand off 450 Ohm well-insulated ladder line,
for years, with no measurable ill effects at all. The line normally hangs a
few inches away from the tower, but in the wind, can bang into the tower --
doesn't seem to matter much. Even running 1500W through it when this
occurs, I've never had it "flash" through the insulation, and never note any
large changes in match.)
"If everything seems under control, you're just not going fast enough." -
> -----Original Message-----
> From: firstname.lastname@example.org [SMTP:email@example.com]
> Sent: Friday, August 23, 2002 10:12 AM
> To: firstname.lastname@example.org
> Subject: [Towertalk] Ladderline near tower
> I'm thinking of trying a dipole fed with old-
> fashioned 600-ohm ladderline.
> It occurs to me that, because the dipole will be
> center-hung from my tower, that I might ought to pay
> more attention to interaction possibilities with this
> feedline than when feeding a wire antenna with coax.
> Any advice/warnings about how to approach a tower-
> hung dipole with open-wire feeders?
> Mike, KØMYW
> Self Supporting Towers, Wireless Weather Stations, see web site:
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