Jim:
Insulated wire is more durable than bare in radial applications. The
soil pH is kept away from the (presumed) copper wire inside the insulation
so the wire will last longer in all soil types than will bare wire.
Insulated wire is also more resistant to mechanical nicks that occur due to
frost heave moving rocks against the wire.
As for the velocity factor thing, forget it. Once the wire, bare or
otherwise, is in contact with earth, the capacitance of the wire to earth
swamps out any transmission line features of the wire. So you can even
shorten the radials and add more of them. The amount of earth you cover
with wire is the key to planting a successful radial garden on Topband. Of
course, if you have that much wire available, then by all means use long
radials.
73 de
Gene Smar AD3F
----- Original Message -----
From: "Jim Hoge" <knowkode@sbcglobal.net>
To: "topband reflector" <topband@contesting.com>
Sent: Wednesday, December 02, 2009 11:08 AM
Subject: Topband: insulated vs:bare radial wires
Greetings,
Can I expect any noticable difference using an insulated wire for radials?
Theoretically, the velocity factor of the insulation will make the physical
length shorter but is a tuned 1/4 wave radial length that important when it
is buried or laid on ground? The plan is to use 18ga awb, of which I have
some 30k feet at my disposal.
tnx,
Jim W5QM
_______________________________________________
160 meters is a serious band, it should be treated with respect. - TF4M
_______________________________________________
160 meters is a serious band, it should be treated with respect. - TF4M
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