this whole topic/conversation shows a pretty good reason to have
professionals install subpanels.
All the advice, recommendations involving SPG and so on sound great and i
won't argue with them as they are correct, but whenever professionals start
advising hams on grounding, protection, and so on, they often overlook one
major thing--hams usually have stations in homes. Homes are almost never
constructed to be telecommunications sites. So all the wonderful advice
the professional is giving, where in his mind, he is picturing cable trays,
backhoes and ditch witches digging trenches everywhere, with gravel all over
the ground and the power company coming in with a bucket and three hard hats
to put the 3-phase line just where you want it--and when he's done talking
the ham says thanks and goes home and unplugs everything and that's the end
of that. I mean, i'd like a little more realistic advice for some guy in a
house who can't move the service drop around back where the tower is, and
can't dig a 4' deep trench all the way around the house and cadweld
everything to a 4" strap.
costs: i once added up the cost of all the polyphasor stuff to do the job
right and came up with around $2K. This is nothing for a guy with $20K in
this hobby, but some guy with 2 grand in it will probably balk at that.
why do hams not spend the money on gas discharge devices and all the other
gear? there's a cost/fun price point somewhere in there where a lot of us
make spending decisions that aren't always logical or rational--we'd rather
blow our money on the fun stuff and take our chances, because that's what a
hobby is about, having fun. I'm not saying that's always okay; i'm just
saying that's how it is.
one final comment: an all out professional protection job doesn't guarantee
you will always be protected--if you don't believe me ask a broadcast
station CE. i know of one A1 station near me that took a direct hit on
their 190 degree tower (probably a positive strike) and lost their nice,
fairly new s.s. tx--had to get a new one.
rob/k5uj
<<<Can you really HAVE a single point ground? Even if the RF and power
service
entrances were immediately adjacent, and tied together with 3" strap...the
drop circuits from each will follow different paths, and may have induced
current on them from the primary strike...with different potentials due to
their geometries. I still disconnect everything in the main shack.
In a 24/7 broadcast installation, or amateur repeater, you clearly can't do
that. You take reasonable precautions, and hope for the best.>>>
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