[Elecraft] static charges
Dale Putnam
daleputnam at hotmail.com
Thu Apr 21 23:05:51 EDT 2011
Hi Scott,
I've drawn an arc from an 80m dipole at 30 feet on a dry sunny day, with the dry south wind blowing, that is over a half inch long... and it is repetitive. That is enough voltage and current to cook most any solid state device.. ... and will do damage if left to its own accord. What I get from my antennas now, that are 360 foot long and at 50 feet, is absolutely astounding, when observed in a dark room, from the open line feeders.
What to do? Simple, and it works right easy too. Provide a straight... no.. really straight line to ground from the feedline.
If you are using coax, then a gas tube discharge will work, and ground it with a very straight to ground path. No bends. And at the shack end, put a connector.. or coax T in the line, and solder a 1 meg resistor across the bottom of the T, from center to ground.
That eliminates the static. Yes, you'll still need to disconnect when not using.. but it will allow you to use the antennas when the wind blows and the lightening isn't.
Now for open lines.. it is even easier. when the line gets close to entry, take a gas tube discharge on each line.. and put the 1 meg resistor from each side of the feedline to the case or shell of the discharge. Keep them in a sheltered from rain case... that works well with a sealed like a Glad or Rubbermaid container.. with slits cut for the feedline to go through.
Now you're safer from all the tracks of loose and unguided electrons that are of a mind for wanton distruction.
good luck, and remember.. disconnect is always best.. IF it is a long ways away from anything else.
--... ...-- Dale - WC7S in Wy
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