On Wed, 2009-04-08 at 18:20 -0500, Stuart Rohre wrote:
> If you have a tower 150 feet from the shack, you should not rely on
> either coax shield or an added copper wire to house, for bonding the
> tower to earth. Use earth rods at the tower, preferably one on each leg
> to spread out any charge. Bring off the feeders underground if possible
> in PVC conduit if you can't afford metal.
> Have provisions for disconnection of feedlines and coax at the entry
> earthing plate outside the shack when not in use and preferably ground
> those feeders. Disconnect electric power from all devices inside the
> shack when it is not in use. Don't operate when lightning storms are
> within 10 miles. It is common for lightning to travel 10 miles and the
> direction is not always vertically. Besides as a storm approaches, wind
> static builds up charges on antennas that can harm rig inputs. Such
> charges have been measured at Field Days on large wire antennas to
> exceed 600 volts. This was from a 10mph or less wind!
> -Stuart Rohre
And make those disconnects give at least a couple feet of air gap EVERY
TIME. My shack has been damaged twice when the gap was small. A switch
won't cut it, unless its made to hold off more than 100 KV.
73, Jerry, K0CQ
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