[Elecraft] [OT] A dumb question about lightning

Fri Jul 28 18:51:29 EDT 2023

We're in accord on static.  Like lightning, give it someplace to go 
OUTSIDE, not via the shack/structure.  Not just for noise but the 
voltages can be astoundingly high with enough amperage to cause harm.

[A local puts his feeds in a glass jar then is amused at the glow of 
discharge, contained.  But that is FAR from the only wire exposed.

These are complex topics that few can translate well to low dollars 
(hams) and better understanding.

It would have been fun to draw on that lunch crowd discussion.

The only true axiom is that if you don't have enough shunting, lightning 
will be happy to show you what you missed.  (Antenna didn't fall over?  
It's not big enough!).

73 Bill,
Rick nk7i

On 7/28/2023 3:36 PM, Dr. William J. Schmidt wrote:
> I worked at Honeywell defense systems in the early 80's and I had two guys (Ph.D's from MIT) working in the office next to me that were experts in Meteorology... specifically the study of lightning.  I would eat lunch with them because they were "interesting" to say the least.  When they found out I was a ham and asking them about lightning protection they laughed hysterically.  Over their tenure they schooled me on my lack of knowledge in their area and beat into me immense gravity and consequences of a major lightning strike.  Imaginable voltages and currents.  You can prepare but you will never be sure.
>
> Static is something else.  All of the antennas I design and implement have GROUNDED elements or static chokes to ground to reduce static to a minimum.  You learn this with experience.
>
>
> Dr. William J. Schmidt - K9HZ J68HZ
>
>
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net <elecraft-bounces at mailman.qth.net> On Behalf Of Rick NK7I
> Sent: Friday, July 28, 2023 4:42 PM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] [OT] A dumb question about lightning
>
> Not often (enough) does a ham have a 100'+ tower either.  😉
>
> THE standard (of way so many to choose from) is from the cell phone industry (Motorola mostly).  It's insanely complex but if you're on a mountain top and need 100% reliability; ideal.  The costs, will be a second mortgage so some compromises will have to happen.
>
> Here is a better link to the current (newest edition) of the ARRL book; at least a good starting point for a baseline understanding.  Direct hits, no matter what system/s used, will always show what you missed or didn't do enough to mitigate.
>
> https://a.co/d/01vRC1W
>
> Another aspect is static reduction.  That comes from wind, rain, dust, snow, anything that passes by the structure.  Shunt all to ground OUTside the building is the best approach.  (Base of the tower/mast and again at structure entry; make EVERYTHING at the same ground potential, inside and out.  When you take a hit, that potential rises, equally if all is done well; it's the difference in potential that harms.)
>
> 73,
> Rick nk7i
>
> On 7/28/2023 2:31 PM, Dr. William J. Schmidt wrote:
>> Even the methods in that book are considered sub-standard by the broadcast industry...  The only think that is a sure bet is to completely disconnect your radio and put it back in the shipping box.
>>
>>
>> Dr. William J. Schmidt - K9HZ J68HZ
>>
>> email:  bill at wjschmidt.com
>>
>>
>> -----Original Message-----
>> From: elecraft-bounces at mailman.qth.net
>> <elecraft-bounces at mailman.qth.net>
>> Sent: Friday, July 28, 2023 4:14 PM
>> To: john at kk9a.com
>> Cc: Elecraft at mailman.qth.net
>> Subject: Re: [Elecraft] [OT] A dumb question about lightning
>>
>>
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>> Welcome to the Bible of grounding.   It’ll take several reads to grasp what you have to do.
>>
>> 73,
>> Rick NK7I
>>
>>
>>> On Jul 28, 2023, at 2:11 PM, john at kk9a.com wrote:
>>>
>>> I would recommend that you follow proper lightning bonding/grounding
>>> techniques, these are the only methods that work. My tower has taken
>>> a number of lighting strikes. You cannot prevent a lightning strike.
>>> Simply disconnecting your feedling will not prevent damage inside
>>> your house as the voltage from a strike will be induced into your home's electrical wires.
>>>
>>> John KK9A
>>>
>>>
>>> Al Lorona W6LX wrote:
>>>
>>>
>>> Please don't laugh at me; I'm a transplant from a region of the
>>> country with essentially no lightning to a region where you have to
>>> worry about it quite a bit.
>>>
>>> We had a doozy of a storm last night, with lots of lightning overhead.
>>> I felt like a sitting duck, even though I had grounded both sides of
>>> the balanced feedline of the antenna, switched the antenna switch to
>>> the middle
>>> (grounded) position, and even disconnected the coax leading to the
>>> K3's rear-panel antenna port.
>>>
>>> Whenever lightning happens, I always wonder if it really is in fact
>>> better to ground everything. Because, doesn't that essentially make a
>>> lightning rod of the antenna? If I simply disconnected the antenna
>>> and left it floating, wouldn't it be less likely to attract a lightning bolt?
>>>
>>> I'm of the belief that it's better to try to avoid a direct hit than
>>> to attract one and trust your grounding system to do its thing. I'm
>>> of the belief that no grounding system is perfectly effective.
>>>
>>> Al  W6LX/4
>>>
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> ______________________________________________________________
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