[Antennas] Re: putting up a vert

Wed Aug 31 12:15:38 EDT 2005

Recall the problems that the early Belden 9913 series had 
with this? ... and "higher SWR" was not always a clue to this.
Higher losses can result in LOWER SWR ... or the appearance
of such ... there's the questions ... is what we "see" on the
bridge in the shack ... really accurate? Well, aha ... ...
<Exceptions are ... exceptions!> B-)
73 Billy AA4NU
-----Original Message-----
From: Roy Koeppe <royanjoy at ncn.net>
Sent: Aug 31, 2005 11:36 AM
To: Antennas reflector <antennas at mailman.qth.net>
Subject: [Antennas] Re: putting up a vert
"Not sure that is a real objective measurement ... as in if the
losses of the coax were to go higher, will the SWR change much?"
Several of my friends have indeed experienced an immediate increase in
SWR even when just a portion of their coax got damp inside. My coax is
'poor man's helix' which is mostly air dielectric with a skinny spiral
of the normal insulator supporting the center conductor, a 9 gauge
stranded wire. At 1500 watts, I'd suspect any resistive losses would be
dissipated as heat, vaporizing the moisture and venting it into the
shack end. However, the outer jacket of good coax is very much water
proof. That is its main purpose! Pills come in thin plastic bottles to
protect them from moisture, etc. My gasoline can is made of
plastic--hasn't leaked yet.
73, Roy K6XK/0
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