I've recently moved to north-central Florida and want to get a couple of
multi-band antennas going this fall. The plan is to install a 43-foot
vertical and a 135-foot doublet fed with ladder line. In both cases I'll
place a remote matching network at ground level, and run coax and control
lines for the matching network from there into my shack in a shallow-ish
trench (possibly with conduit) and through an entrance panel. I will run a
ground wire in each trench with the coax, and will install ground rods at
both ends of each trench and at intervals along the way. The entrance
panel will contain a grounding plate on which lightning arrestors are
located, and I'll run a ground wire (or a wide copper strap) from the
grounding plate to that ground system, and to my electrical service ground
rod. I'm looking for an acceptable way to bond the ground wire and copper
strap to the ground rods. I've seen the term "cadweld" used, and I watched
a utility crew use an exothermic weld technique to connect a ground wire
to a ground rod at the base of a utility pole on my property. I have no
direct experience with the process.
Looking at on-line catalogs I see reusable molds for various
configurations, clamping "handles" and welding powder all sold a-la-carte.
I have not seen a mold that would work to connect wide copper strap to a
ground rod.
The utility crew didn't use a reusable mold, it was what looked like a
ceramic cylinder that they placed over the connection and left in place
when the weld was complete.
I imagine that the single-shot mold might be faster to use but more
expensive than a reusable mold. If each trench run is 100 feet and I use
10-foot ground rods spaced at 20 feet, that's a total of 12 ground rods to
bond to including the existing electrical service ground. So its probably
going to make sense to buy reusable molds and a clamping handle. Are there
tradeoffs other than cost that I should consider? Does it really make
sense to buy two different molds, one for "T" connections and another for
a dead-end connection, or can I use the "T" mold for everything with just
a stub of wire on the second port? Is there such a thing as a mold
(one-shot or reusable) for bonding wide copper strap to a ground rod?
I'm looking for advice and opinions as well as information. Is my plan
reasonable? Suggested reading and sources for the molds, etc. would be
appreciated.
TIA.
--
Art Greenberg
WA2LLN
art@artg.tv
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