While Im not in a high lightning area we do get some beauties plus Im on top
of an exposed hill. The #18 insulated and stranded used on the old Beverages
was fine when removed after 20 years and reused as were the same type that
were relocated for raised radials. It was all part of a pair of 5000' reels
I picked up at a hamfest in the late 80's for cheap since scrap was at the
bottom and radial material wasnt popular yet. Finding large reels at any
price these days at a hamfest is slim to none.
Carl
KM1H
----- Original Message -----
From: "Tom W8JI" <w8ji@w8ji.com>
To: "Bob Kupps" <n6bk@yahoo.com>; "topband" <topband@contesting.com>
Sent: Tuesday, September 18, 2012 7:59 AM
Subject: Re: Topband: intersecting ground radials
Hi I would like to place monopoles for 160 and 80m bands 30m apart
causing their ground radials to intersect. The radials are #20 bare
copperweld (since I happen to have 4000m) that would be laid out on top
of the soil before turf was placed on top. These antennas would be used
for transmitting only and never at the same time. Is it necessary to
solder the intersecting wires together where they cross for any reason
like they recommend for phased arrays? Naturally I hope not...>>>>
They either should be soldered together, or well separated. The last thing
any of us want is a poor connection. A poor connection can make RF noise
or rectify and mix signals, and a close spaced connection can arc and make
a heat source that literally can cause wires to blow apart in lightning
hits.
I hope you are not in an area of severe lightning if you are going to use
#20. While I get away with #16 without any issues at all in repeated
direct lighting hits, I would not risk #20. Maybe if you had many radials
#20 would work, but otherwise there is some danger you could reach the
fusing current limit.
Fusing current of #20 is 58 amperes, which is half of #16 and one quarter
of #12 AWG copper. I use a minimum of 30 long radials of number 16 and
have no problems with lighning melting wires **IF** they are not laying on
other conductors with poor connections.
I left a piece of guy strand laying on the ground below a tower, where it
crossed both a large heliax cable and a wide copper flashing. After a
strike or two I found it had melted the wide flashing and blown a hole
through the heliax jacket. I sure learened a lesson on "close but not
bonded" conductors!
My arc welders don't melt the very thin welding wire except at the arc
point. :-) My experience is this carries over to unintentional arcs.
73 Tom
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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