Topband: Spark gaps

[Tom W8JI]

> Man, I don't know, Dave. How long have they been selling those carbon 
> balls
> for that purpose?

I've never seen a carbon ball in a lightning gap application. I'd have to 
see a few after being in action a long time before trusting them.

Broadcast stations use hard metallic balls, as do electrical substations and 
other applications where the peak voltage is near gap voltage. Polished 
round gaps have more consistent breakdown.

If there is a great deal of headroom between operating and breakover 
threshold, a pointed gap works OK.