[TowerTalk] (no subject)

[K7GCO@aol.com]

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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