Date: Fri, 23 Dec 2016 07:54:06 -0600
From: Patrick Greenlee <patrick_g@windstream.net>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Double Coax Runs to Reduce Loss
The skin effect will not force all the current to flow in a corroded
surface layer with good copper below it. Current density will be
distributed proportional to the impedance presented by the different
depths. This includes the skin effect's redistribution of impedance.
If a simple application of irrefutable skin effect phenomena were
applied, the insulation over copper wire would be the current carrying
medium at RF freqs rendering insulated wire unusable in most applications.
Except as specifically noted above I mostly agree with the post
reproduced below.
It might be interesting to put a watt meter first at one end of the DIY
twisted pair and then at the other end and see what the efficiency is.
Why debate the number of angels dancing on the head of a pin when we can
use a loupe and count the little buggers?
Patrick
## I dont get it. As long as the wire is terminated correctly, any
deterioration of the
THNN insulation should not enter into the equation. Copper tubing, used in 144
mhz,
2 kw tube amps can turn GREEN..and or black,and zero redux in po....as long as
the tubing is terminated
correctly.
## IF the terminations are done right.... and the thnn insulation turns
crumbly, the RF current should travel along
the inner layers of cu wire, just below the top later of cu.
## It might be a case where the bad THNN insulation has somehow migrated into
the termination, dunno.
## f12 used 12 ga THNN wire...home depot stuff, to wind the coils in their
ssb – cw switch boxes. But
they used nema boxes, and the coils lasted a long time..so no UV. I initially
replaced em with 8 ga polyimide
magnet wire, then later on with silver plated 1 inch wide cu strap.
Jim VE7RF
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