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 Post subject: Mothballed solid state receivers in lightning prone areas
PostPosted: Sep Sat 11, 2021 5:10 pm 
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Joined: Jan Sat 18, 2020 4:37 pm
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Would shorting the antenna input to the receivers chassis gnd be of any benefit from nearby lightning strike effects (say, to prevent desensitization), and and/or should the short involve a resistor of any particular low/high value to that same end?


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 Post subject: Re: Mothballed solid state receivers in lightning prone area
PostPosted: Sep Sat 11, 2021 5:20 pm 
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Luvfrg wrote:
Would shorting the antenna input to the receivers chassis gnd be of any benefit from nearby lightning strike effects (say, to prevent desensitization), and and/or should the short involve a resistor of any particular low/high value to that same end?
Shorting the antenna connections directly wouldn't hurt, but is probably unnecessary. The short wires internal to the radio won't normally pick up enough of the electrostatic field from nearby lightning strike to amount to anything.

Now if the radio was attached to an outside antenna that would be a whole different story. I've seen a disconnected outside antenna produce 1/4" sparks from center terminal to shield on a coax connector WITHOUT an actual lightning strike (thunderstorm in the area). I've also had an outside antenna partially vaporized along with completely vaporizing 100 ft of RG58/U coax (all that was left was black soot) from a direct strike (radio equipment had some damage but survived).

Also, EMP would cause a problem with a radio even without an antenna. However, under those circumstances one would generally be more worried about the cause of the EMP and survival than whether a radio got damaged.

Curtis Eickerman

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 Post subject: Re: Mothballed solid state receivers in lightning prone area
PostPosted: Sep Sat 11, 2021 5:26 pm 
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Put radio in gasketed ammo can w/silica gel packet. Mark "Radio" so not to confuse with real ammo in emergency.

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 Post subject: Re: Mothballed solid state receivers in lightning prone area
PostPosted: Sep Sat 11, 2021 6:21 pm 
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When I leave my cabin in the mountains, I disconnect the antenna from the house and coil up the wire away from any grounds (wire fence). A good antenna distribution switch for changing radios inside the station shorts the unused radio positions to ground.

Norm

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 Post subject: Re: Mothballed solid state receivers in lightning prone area
PostPosted: Sep Sat 11, 2021 8:11 pm 
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Joined: Jan Sat 18, 2020 4:37 pm
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I guess that I got the resistor idea from the discharging of electrolytic capacitors...
one can maintain a DC charge just by laying around dormant (kinda like lightning??).
If one wants to discharge electrolytics while maintaining its health, a resistor is often recommended.
In the case of lightning, however, I guess it's on an opposite (disconnected?) end. Besides, if it's
ever THAT close, then I would probably have much MORE to worry about :shock:

Here in FL, I use SO-239 bulkhead connectors through spray-painted wood paneling,
and pulled quick-disconnects (for my active units).

...And microwave ovens converted into Faraday Cages :wink: How's that, Chas? :D
...in the case of EMP, Curtis can be a Wise Man/Sage/Yoda of radio ("I remember when...") :)
...you, too, Norm...shall we start with galena rocks and cat whiskers? :lol:


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 Post subject: Re: Mothballed solid state receivers in lightning prone area
PostPosted: Sep Mon 13, 2021 7:34 pm 
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 Post subject: Re: Mothballed solid state receivers in lightning prone area
PostPosted: Sep Tue 14, 2021 3:36 am 
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Joined: Dec Sun 25, 2016 5:53 am
Posts: 402
Luvfrg wrote:
I guess that I got the resistor idea from the discharging of electrolytic capacitors...
one can maintain a DC charge just by laying around dormant (kinda like lightning??).
If one wants to discharge electrolytics while maintaining its health, a resistor is often recommended.
In the case of lightning, however, I guess it's on an opposite (disconnected?) end. Besides, if it's
ever THAT close, then I would probably have much MORE to worry about :shock:

Here in FL, I use SO-239 bulkhead connectors through spray-painted wood paneling,
and pulled quick-disconnects (for my active units).

...And microwave ovens converted into Faraday Cages :wink: How's that, Chas? :D
...in the case of EMP, Curtis can be a Wise Man/Sage/Yoda of radio ("I remember when...") :)
...you, too, Norm...shall we start with galena rocks and cat whiskers? :lol:

My best Faraday Cage is the one made by Amana. One feature I like about it is that it can be quickly repurposed and used for heating foodstuffs.

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