Thanks!
From: Mike Waters [mailto:mikewate@gmail.com]
Sent: Saturday, June 27, 2015 6:20 PM
To: Charles Cunningham
Cc: topband
Subject: Re: Topband: A Bit Off Topic
EHam is back up; here it is:
www.eham.net/ehamforum/smf/index.php/topic,102393.msg834797.html#msg834797
It's a long post, but no one complained since there's so much good info in it.
John is a smart fellow.
73, Mike
www.w0btu.com
On Sat, Jun 27, 2015 at 5:14 PM, Mike Waters <mikewate@gmail.com> wrote:
Hi Charlie,
On Sat, Jun 27, 2015 at 4:06 PM, Charles Cu nningham
<charlie-cunningham@nc.rr.com> wrote:
Well, a few things to keep in mind, Mike:
· Each time an MOV breaks down, Its breakdown voltage decreases a
little, taking its break down voltage closer to the peak voltage of the line
cycles.
Understood.
That Sycom meter base surge suppressor has been replaced three times at my
request. The last time, I made sure that it was a brand-new unit for the very
reason that you state. Still, it didn't work like I thought it should.
Regarding ground rods – if the ground rods take lightning strikes, the soil
around the ground rod can “glassify” become glass from the heat of the
lightning surges. As the soil glassifies, the rod is then surrounded by an
INSULATOR – making it rather ineffective. It can be a pain, but it’s worth
checking ground rods from time-to-time for degradation.
WOW! That's something that never occurred to me.
Here's a class-act company that specializes in very low resistance grounding
systems for as-good-as-it-gets lightning protection.
http://www.lyncole.com
A local friend of mine (W0PM, Rayfield Communications) has successfully
Lyncole's products on several tall commercial towers. They use a special ground
rod along with a thick layer of a powdered(?) chemical mix that surround it.
John is quite knowledgeable about this. If eHam were up, I'd send you a link to
something he said there.
In keeping with Tom’s remarks, the meter-base suppressors ARE common-mode
suppressors that sit directly across the 240 volt line phases with a direct
common-mode ground return.
I cannot think of a way of (or reason for) wiring a 240 volt 3- wire surge
suppressor so that there is only common mode protection but no differential
mode protection. How could that be the case? If there are two 130 VAC MOVs from
each leg to ground, wouldn't both of them conduct if a HV spike was present
across both legs?
73, Mike
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