[TowerTalk] Power ground
Tom Rauch
w8ji at contesting.com
Wed May 26 14:49:43 EDT 2004
> Additional radials will always help. No detriment to this.
However using
> brazed water pipes is not recommended. The brazed
connections represent a
> seriously weak electrical joint and may fail prematurely
under thermal
> stress of high currents.
I'd normally agree if the joint was with two pieces laid
together, but with pipe inside pipe even solder sure seems
to hold fine. My primary ground for my shop is copper
flashing along the walls, and it feeds out via 3/4" copper
water pipe with an elbow downturn and an elbow out-turn. My
primary tower ground has a similar system in a repeater shed
and tower ground at the tower base.
Even though my recent "big hit" melted shields on 7/8th
heliax, melted some 3" wide flashing, and blew connectors
apart (and a few F-11 and copper shielded underground telco
cables 1/4 mile away from the tower!) all my pipe joints
remain solid. This is true both at my shop entrance and at
the tower.
Has anyone on this reflector honestly ever seen a large
diameter properly soldered water pipe joint fail in
lightning hits? I've never seen it fail anywhere, not even
in AM BC systems that take hit after hit. I can't imagine a
braised overlapped joint failing.
73 Tom
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