[Amps] flash arcs

[Tom W8JI]

> According to Gossling's paper in the Journal of the IEE 
> (which means it was certainly peer reviewed!), flash arcs 
> is slightly affected by residual gas: the 'clean up' 
> effect of the arc can lower the flashing voltage. He 
> recommends series resistance in the anode supply (now 
> where have we seen that recommended!) but says that it 
> isn't generally pracitcable with valves over 10kW. He 
> comments that the 'most general visible after effect is 
> widespread tree like markings on the grid and filament 
> supports. The fine wires in the active part of the grid 
> are, however, never damaged.'

That's exactly the type of damage I have seen. As I posted 
earlier, 3-500z's generally mark the grid support cone at 
the bottom with very fine lines.

73 Tom