[time-nuts] Loran, GPS, Lightning, Timing

Bill Hawkins bill at iaxs.net
Wed Jun 25 19:47:36 EDT 2014


A couple of other things about dealing with lightning:

There is a cone of protection starting at the highest grounded point
around for about 100 feet.
These were developed to protect explosives bunkers from direct hits.
The angle of the cone (between a vertical line to the tip and the edge
of the cone) is 30 to 45 degrees.
Exceptions have been reported, of course. That should save you from most
direct hits.

Then you have to deal with the electric field that builds up from
passing charged clouds.
Some kind of high-value resistor in parallel with a small glass sealed
spark gap from antenna to ground would help.
It doesn't have to deal with a direct hit, just keep the grid from
arcing in the tube.
Some of the sealed spark gaps also contain inert gas. You don't want a
triggered spark gap, just a surge suppressor.

Old radios with octal sockets had tubes in the RF and IF amplifiers with
grid caps, like the 6K7.
Should be a lot more available than the Boonton 535-A.

Bill Hawkins



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