Ah, some more interesting comments. My needs are quite immediate as I am
working on the system daily. I will have about 100 radials per vertical,
plus 200 or more connections out in the radial field where the radials
intersect and of course not all the pieces of wire will be long enough so
there will also be a multitude of splices. So my interest in connections is
very high! For the 300 or so radials that come up at the base of the
radiators, I can see the possibility of using water resistant wire nuts.
They are simple and can be checked easily. The standard technique is to use
a clip-on current meter and look for anomalous currents (or more likely the
lack thereof). For the 200-300 connections out in the field things are not
so easy however. The idea of silver soldering or similar high temperature
work on 300+ connections does not thrill me but would rather get it right in
the beginning. Working with oxidized wire or corroded connections is ten
times worse than getting it right the first time!
For wire I have started by buying 10,000' of #12 THHN from Home Depot. Cost
me $80 for a 2,500' roll - 3.2 cents/foot. I will use this for the backbone
of the radial system but don't want to continue spending that kind of money
for radial wire since I need a lot more. I think I will pursue some of the
leads suggested by all of you and really do appreciate it.
The basis for believing that radial wire size is not a significant factor
begins with the Brown, Lewis, Epstein, 1937 IRE paper. In figure 15 they
showed a graph of current versus distance along a radial for a 15 radial
system and it is obvious that wire size has little effect. The graph is for
wire sizes from #2 through #14. The equation behind this graph is given in
the paper. The equation was derived from both analytical and empirical
considerations and was experimentally verified. It is not exact but is
thought to be pretty close to reality. That sets a fairly authoritative
precedent so eyebrows are raised when data contradicting this appears. That
doesn't mean that BLE and the broadcast industry couldn't be wrong but you
would have to make a pretty good case to change minds.
Keep in mind that compared to almost any reasonable conductor, most ground
is a truly terrible conductor. The idea is to keep the current from flowing
in the highly resistive soil.
Thanks again, 73, Rudy N6LF
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