[Elecraft] Prevent Snow/Dirt Static damage to KPA100 after upgrade

[Ron D'Eau Claire]

You suggest a great technique to keep the charge at a safe level, Ken. 

Some people advocate using an RF choke from the feeder to ground. That works
FB too if the impedance of the choke is 10 or 20 times greater than the
feeder impedance. The problem is that RF choke are series resonant at some
frequency. When that happens it becomes an RF short. First most of the RF
power gets burned up as heat in the choke. If close enough to resonance the
choke literally "smokes" and self-destructs. 

Been knocked on my behind from the static charge on a disconnected 100-ft
end fed wire antenna when I unthinkingly touched it. 

I always *ground* the antenna feeder any time it's not hooked to the rig.

Ron AC7AC

-----Original Message-----

40 years ago we had a windy dust storm in Bismarck ND and I lost the RF 
amplifier in my new solid state Heathkit receiver three times that day 
before I realized the dirt and high winds were putting a static charge 
on my antenna. I found there was a capacitor between the antenna and the 
RF amp and the static would arc across the capacitor  and burn out the 
RF amp. Of course tube type receivers did not have this problem. I found 
out a 100K resistor from the antenna to ground would prevent this and 
not load down the antenna...

Ken  W0CZ