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Re: Topband: Soldering radials?

To: "topband@contesting.com" <topband@contesting.com>
Subject: Re: Topband: Soldering radials?
From: Donald Chester <k4kyv@hotmail.com>
Date: Sat, 22 Oct 2016 05:45:58 +0000
List-post: <topband@contesting.com">mailto:topband@contesting.com>
I installed my buried radial system in 1983, using #12 bare soft-drawn copper 
and it is still in near-perfect condition.  The radials were soldered to the 
common  point at the base of the tower, a copper ribbon laid around the 
circumference of the base of the vertical, using a 15% silver alloy purchased 
from a plumbing supplier.  It comes in flat sticks, 18" long and about 1/8" 
wide. I use a Mapp Gas brazing torch; a regular propane torch won't get the 
copper hot enough. No flux is necessary. Copper soaks the stuff up like a 
sponge soaks up water.  Just brush off any scaly crud from the copper and the 
heat from the torch  will burn off the rest.  The copper is heated to a barely 
perceptible dull red. Be careful not to overheat the copper; I accidentally 
melted the ends of a couple of radials into a blob but fortunately had enough 
slack in the wire to pull it tight and retrieve enough length to make the 
connections having to splice anything.  After 33 years those brazed connec
 tions are just as good as the day I installed them.  The soil here is PH 
neutral and pretty benign to copper; after all these years the radials show 
very little deterioration.

Decades ago before I knew better,  I had used regular lead/tin solder with my 
first radial system, but the minerals in the soil turned the solder into a 
white powder in just a few weeks and the connections would literally fall 
apart.  I ended up having to routinely re-solder the radials about once a month 
throughout the radio season.  It is against code to use lead solder in plumbing 
for two reasons: the lead may react with minerals and leach into drinking 
water, plus this eventually causes the soldered connection to deteriorate and 
pipes to leak.

Commercial communications and broadcast systems DO NOT overlap radials in a 
multi-tower array.  A straight line is drawn between the bases of the towers, 
and a second straight line is drawn perpendicular, at the mid-point of the line 
between the bases of the towers. A copper conductor is laid out along that 
perpendicular line.  The radials to each tower are terminated and soldered to 
that perpendicular conductor, with no overlap between the two radial systems.

Don k4kyv
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