Lynn makes a good point. Our club station helper grounded every rig
negative and every chassis to earth bus. Of course there was coax to the
VHF/UHF rig. The lightning surge came down the shield of the coax from the
tower, into the radio on coax connector and back to AC ground thru the DC
negative copper of the circuit board, (until that vaporized). We had
created a ground loop. In this particular hit, the AC ground looked lower
impedance than the bronze strap bus,and its connection to cold water pipe
just outside the wall. (2 foot of braid to it).
How you treat grounds can be a damaging situation.
Total disconnection of the coaxes at entry to building when not in use would
have make a bigger spark gap for the current to cross than the circuit board
did.
We had survived a direct hit on the power pole 100 feet across the parking
lot some years before. The 65 foot tower usually discharges the
surroundings to its earth rods.
Stuart
K5KVH
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|