[Elecraft] OT: Ground rods and concrete

[Matt Zilmer]

Time to update that list of frequently misspelled words. It is very 
long, but also distinguished.

How about it's versus its?  The first is a contraction, and the second 
is a possessive.  I think, from experience, that this is the single most 
common spelling error that I see from English-first writers.

/me ducks.  I'm SURE this is off topic.

73,

matt W6NIA


On 4/18/2017 5:03 PM, Randy Lake wrote:
> This has been bugging me for a while and I am now in a mindframe to comment.
> Lightening:
> light·en·ing
> ˈlītniNG/
> *noun*
>
>     1. a drop in the level of the uterus during the last weeks of pregnancy
>     as the head of the fetus engages in the pelvis.
>
> Come on !!
>
> Randy
> N1KWF
>
>
> On Tue, Apr 18, 2017 at 7:39 PM, Ken G Kopp <kengkopp at gmail.com> wrote:
>
>> I was the first to use the term "exploding tower base" in this discussion.
>> The term "exploding" was probably not correct.  As several others have
>> phrased it, an instant expansion of steam is more correct.  Concrete is
>> never totally "dry" in the context of this conversation.
>>
>> I witnessed lightening blowing apart the two tower bases I spoke of in
>> person, directly, and in real-time. It happened in the mid-sixties at the
>> St. Petersburg, FL Coast Guard base.  As someone else has mentioned;
>> the Tampa Bay region has the highest incidence of lightening in the
>> Western Hemisphere.  To the one of you who accused my of lying ...
>> I was there ... you weren't.
>>
>> At the time I was an ET aboard the USC&GS (Now NOAA) Oceanographic
>> Survey ship Hydrographer/WTEI and we were in the area deliberately
>> attracting lightening with balloon-hoisted cables.  I -do- know something
>> about the infinite uncertainty of lightning.
>>
>> I'm a retired electric power company two-way radio tech and have probably
>> dealt with more types of towers than most of you.  Large electric
>> transmission
>> line towers are almost always set on four concrete piers, and are grounded
>> with (usually) copper straps cad-welded to each tower leg and connected to
>> ground rods a bit away from the cement.  Each of us can search long enough
>> to find "facts" that support our various positons, especially on today's
>> Internet.
>>
>> Here in the mountains of the West ... as well other regions ... finding and
>> maintaining a "good" ground at a radio site atop a mountain can be a
>> "challenge".  It's almost never done with ground rods.  My power company
>> employer has several hundred mountain-top microwave and/or radio sites.
>> Been there, done that, as they say.
>>
>> One responder spoke of fitting a copper pipe with a garden hose fitting and
>> "flushing" it into the ground.  That works very well, and is how some of my
>> 14 grounds are installed.  It helps if the downward end is partly
>> flattened, BTW.
>>
>> A much bigger problem overall than lightening is water collecting in tower
>> legs,
>> especially in climates where it can rust (undetected) from the inside and /
>> or
>> freeze and split one or more legs.  There's an accepted way to avoid this.
>>
>> 73!
>>
>> Ken Kopp - K0PP
>>
>>
>> On Apr 18, 2017 at 4:30 PM, <w5sum at comcast.net> wrote:
>>
>>> some 40 years ago, maybe longer I put up a 50' rohn 25G tower. Dug the
>>> hole
>>      and set the tower base in it alone with a 12' 3/4" ground rod and
>> poured the
>>      cement, left about 6" of ground rod protruding. I bonded to that rod
>> and grounded
>>      the tower. 3 years later I had a huge lightning strike on my tower and
>> yes.. it cracked
>>      that base.
>>
>>      never again
>>
>>      Ronnie W5SUM
>>
>>> ______________________________________________________________
>>>
>>>
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>
>

-- 
"A delay is better than a disaster."
-- unknonwn

Matt Zilmer, W6NIA
[Shiraz]