Re: QCX - The Ultimate Walking Dead SHTF TXCVR? A not-so-serious, fun, thinking exercise

Arv Evans <arvid.evans@...>

Way back in the "bad old days" when nylon seat covers and nylon panties first
appeared in automobiles, many car owners installed a ground strap on their
cars that dropped to the ground at slow speeds.  This supposedly prevented
shocks when persons stepped out of the vehicle. 

I do not know if this actually worked or not because I have never worn
nylon panties!  8-)


On Sun, Aug 29, 2021 at 7:49 AM VK5EEE <vk5eee@...> wrote:
Oh yes indeed and it is an excellent example, so much sensitive gear in there and so many direct lightning hits. Of course it was my "humour" about air craft not being grounded, but it is something we don't all think of until it is pointed out and then it is so obvious! Another illustration of the visual/experiential context that is nigh impossible to unsee/forget. 

It was also interesting to learn why some Farday cages, i.e. those humans enter and exit from and could have a hit at that inopportune moment, are grounded. I actually have this amount of congitive recognition/fear when unscrewing a PL259 from gear when a storm is near. I think, with my bloody luck, the antenna may be struck while I'm holding this. If it were, I'd be an unfortunate path to ground. 

I suppose I should at least put down some kind of rubber mat there for those un-screwing operations, to prevent being royally screwed in such an event. I had a friend who was hit more by sheet lighting strike in a field, or a nearby strike, and he was a bit unwell for some days after. Come to think of it, I should probably use thick rubber gloves when disconnecting the antenna. But what are the chances! Never say no?!

On 29 Aug 2021, at 04:02, Julian N4JO <n4jo@...> wrote:

Thanks for the kind words, Lou :-)  I was not an intellectual student at school, I needed visual/experiential context in order to learn things. And as you say very eloquently, "once something is learned in that way it is difficult to forget". To use the visual approach in a metaphorical sense, it is good practice to "step back until you can see the big picture"; in other words, make sure that we are seeing all of the aspects of any situation. it's vey easy to make misleading assumptions, so stepping back to ask the questions we think we know the answers to keeps the mind inquisitive and able to learn.

The reason for reminding us that aircraft are not grounded is that they are excellent examples of Faraday cages - preventing lightning discharge from affecting the delicate electronic equipment in an aircraft - and that as such they illustrate my claim that a Faraday doesn't need to be grounded in order to be effective. Grounding is to prevent electric shock injury to those in contact with the ground.
Julian, N4JO.

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