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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