...."Is it because of some overvoltage issue on the shield? Maybe
letting the coax be the sacrificial fuse (i.e. let it arc
through the jacket) might be a good approach?".....
That is exactly what you are trying to avoid by grounding the coax to
the tower. Replacing all the coax on a tower after a lightning strike
is a difficult way to implement a fuse. Pin holes in the coax jacket
means death of the coax shortly after due to water entrance.
Jerry, K4SAV
Jim Lux wrote:
>Larry DiGioia N8KU wrote:
>
>
>>Could someone please explain how you can ground a coax shield, on a
>>continuous run down a tower, without letting moisture and humidity get
>>into it? Thanks!
>>
>>Larry N8KU
>>
>>
>
>Waterproof N connectors, Female/Female Barrel/bulkhead feedthrough
>that's grounded?
>
>or
>
>Strip outer insulating jacket off, wrap clamp around, solder, cover
>thoroughly or pot it?
>
>
>However, I don't know of a way to do it without cutting something.
>
>Something else to think about...
>
>What's the goal here? Is it to provide a path from top to bottom of
>tower for lightning? I would think the tower is a better path. Is it to
> bleed off static type charges? The shield ground back at the shack
>will do that. Is it to provide a path for induced current on the shield
>from a nearby strike to get back to ground, without propagating to the
>shack? Given the fast rise time, maybe just wrapping the coax in a
>grounded sheath is sufficient, and capacitive coupling through the
>jacket will do the rest? Is it because of some overvoltage issue on the
>shield? Maybe letting the coax be the sacrificial fuse (i.e. let it arc
>through the jacket) might be a good approach?
>
>Just some things to think about...
>
>
>Jim, W6RMK
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