In a message dated 6/18/01 6:33:17 PM Pacific Daylight Time, w5kp@swbell.net
writes:<<
Copper roofing is all the rage for commercial buildings and some high-end
private residences, so my local scrap metal dealer always has a bunch of
leftover pieces on hand from the commercial roofers, who sell him all their
copper roofing scraps. I buy it for $1 a pound, and 5 pounds is a lot of
copper roofing, in pieces 6"-12" wide and 3 to 4 feet long. Cutting it with
tin snips works fine, but will leave an edge you could shave with, so
getting it roller-cut into 1" strips or whatever at a sheetmetal shop might
be a good idea. I just clamped the strips between two pieces of wood in a
vise and cleaned the dangerous edges up with a file. Took a few minutes, but
no big deal. That was one of the several times I wished I had a power
nibbler. I saw a 100' roll of 2" at HamCom in Dallas, the guy wanted $150
for it. Sheesh.
73, Jerry W5KP
>>
A local radio store here called Supertronics has copper sheet 6" wide on a
roll fairly cheap. This would good to lay right on the radio table then run
outside--into the ground without any connections. Take a post hole digger
and dig a hole say 6-8' deep. Run this foil into the hole and pack the dirt
in around it. You will have 6 sq ft of area in contact with the ground. With
a ground rod you have only about 1 sq ft. It's easy to solder any other wires
to it also and there is no change of inductance. This foil in the ground
would be a great way to make a ground for a tower also.
In the 30's it can be seen in old ARRL Antenna Handbooks where they used
copper broilers they used for boiling cloths in for buried grounds. There
was at least 15 sq ft of copper area--on both sides. That's what I call a
"MAGNUM GROUND."
I used to buy copper sheet 3' wide 35' long from Alaska Copper and Brass here
in Seattle also. I'd cut strips of copper that I coated with contact cement
and the element and wrapped it around the elements to eliminate joints and
increase conductivity. I rotated it slowly in the lathe and wrapped it with
plastic tape. Shrink on tubing is too expensive. It's a "Higher Q Permanent
Element." It lowered the Z of the beam. Someday I'll "Silver Plate" the
copper sheet and lower the RF resistance even more. k7gco
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