[TowerTalk] ladder line spacers

Ted Leaf tleaf@hotmail.com
Sat, 20 May 2000 02:54:36 HST


Hi Guys,

I learned a trick from an old-timer.  If you want UV protection--paint it.  
Water based paint works fine.  BTW, I have no trouble sticking it to 
PVC--without primer.  Also, works great on protecting coax from UV.

73, Aloha
Ted Leaf, K6HI
Kona, Hawaii
<tleaf@hotmail.com>

------------------------------------------------------------------------
: Thu, 18 May 2000 02:43:09 EDT
From: K7GCO@aol.com
Subject: [TowerTalk] (no subject)

In a message dated 16.05.00 20:14:23 Pacific Daylight Time,
w9ol@dataflo.net
writes:<<
5, 10, or 20 dollar chips???

----- Original Message -----
From: "Jim Rhodes" <rhodes@willinet.net>
To: <towertalk@contesting.com>
Sent: Tuesday, May 16, 2000 10:03 PM
Subject: [TowerTalk] Ladder line insulators again
 >
 > I know that was 2 weeks ago, but I ran into an old friend
tonight which
 > brought up the memory of the time he needed to feed an
antenna WAY out in
 > the field, several hundred yard away from the house. Being
the thrifty
     type he didn't want to spring for hard line or even
commercial ladder
line.
     What he came up with was 2 rolls of copper coated electric
fence wire
     and a couple boxes of poker chips. He made up a jig to hold
the 2
strands of
    wire the right distance apart, heated the wire with a torch
and melted
the wire
 > right into the poker chips. Quite colorful what with the red,
white & blue
 > poker chips.  No, I don't know the dielectric properties of
poker chips ;-)
 > Jim Rhodes KC0XU
 > >>

     In regard to all the substitutes for open wire spacers,
this one has a
humorous slant to it.  But from a practical standpoint I
seriously doubt the
longevity of them.  The chips (as well as tung depressors) will
have high
wind resistance, the dielectric is unknown and very close
spacing that gives
about 400 ohms Zo.  If the spacing is say 6" the dielectric
properties can be
on the poor side and still be a good spacer.  With say 1.25"
spacing, carbon
paths can formed easily at the high voltage points with a
coating of dust or
smoke type impurities.

There are times when one has to bite the bullet and buy the good
spacer
material like Delrin so the damn open wire line will last.  I
have some with
ceramic spacers that is 60 years with enameled #12 wire.  Now
that is value
received for the cost and time invested.  This open wire line
probably has
carried more RF than any other ham transmission line in use to
day with the
same very loss it had 60 years ago and for the least cost.  No
other
transmission line can make that statement.  Using all these
Mickey Mouse
short cuts and spacer substitutes to save a few bucks is just
not very smart.
Ceramic and even 3/8 or 1/2" Delrin spacers properly attached
to the wire
will eliminate a lot of repeated maintenance.

The plastic used in the coat hangers now appears to be fairly
strong.  It's
small in diameter and will have low wind resistance.  I have no
dielectric
constant info but I'd even try 6" spacers using it.  I saw an ad
for these
hangers for 12 of them and the price was right.  One could make
about 4-6
spacers from each one.  One could even use the curved ends as
long as the
spacing is maintained.  In actual practice the spacing can vary.
It all
comes out in the wash at the end.  If the tuner matches the Z
there, 100%
transfer of the energy occurs to the antenna less the feedline
and tuner
losses which are lower than any other system.  K7GCO

------------------------------



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