I see someone has taken the time to read
and understand Roger Block's book. BTW,
the 3d edition will be out soon. It was revised
and some new stuff put in by Ken Rand who is
PolyPhaser's current resident expert. As some
of you may know, Smith Industries (owns Times
Micorwave) based in the UK bought Poly a number
of years ago and instituted a number of ham-unfriendly
policies and then laid off most of the technical support
staff who knew anything technical and replaced them
with people with some technical background (although
not necessarily in RF and associated specialties) but
who were primarily sales oriented. I was one of those
let go, by the way. For a number of reasons, that is as
far as I want to go about that particular issue.
Anyway, a Ufer should NOT be used as your sole ground
system. The concrete base will not crack if a Ufer is used
and connected to a proper grounding system (as discussed
in the Poly book). In fact, not employing a Ufer could cause
problems in that regard. (Think about it before responding.)
However, the rebar and connecting cables in the Ufer should
not be closer than 3" to the surfaces or, yes, there could be
cracking. This is probably what happened in the few cases
most people cite about concrete cracking.
I would suggest that folks get a copy of Rofer's "Grounds" book.
DavisRF has 'em. You can also try Ron Block, Roger's brother,
who is in southern NJ. I've lost his tel #s, but he's in Clarksboro
if memory serves. He can assist with technical questions and is
also a ham and understands where we are coming from. The
factory is 800 325 7170 but I don't know what their policies on
individuals wanting to buy from the factory direct are anymore.
I believe AES carries the book too. Read the book at least three
or four times. Roger's style of writing leaves something to be
desired and Ken has taken pains to put things in order. BTW, Ken
is also a ham.
73,
Bob AA0CY
ex-PolyPhaser Senior Applications Engineer
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