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Hello Wolf,
Regarding steel wire losses depend highly on the kind of steel and
on the kind of antenna (resonant or not). Magnetic steel should be avoided
because its µrel is unknown and
changes over frequency.
On shortwave I've measured a factor of
~13 steel vs copper for *rf* losses of a 2mm
steel antenna litz
wire, manufactured by a former German antenna producer (Fritzel).
This closely matches with numbers found in Gerd Janzen's book "Kurze
Antennen".
Therefore the efficiency for a half wave dipole is about 89%
(0,5dB)
and 84% (0,76dB) for a fullwave loop made of this type of
steel.
Losses of steel antenna wire really become detrimental if you use
short antennas because of
the low radiation resistance.
So for MW/LW,where most of us have extremely short antenas in terms of
wavelength
steel wire is not advisable for antennas.
Losses of feeders made of steel,with reasonable
diameter (say 2mm) are in the same range
as with resonant dipoles or resonant loops,i.e. neglectable for our
purposes.
73
Clemens
DL4RAJ
----- Original Message -----
Sent: Saturday, November 07, 2009 8:23
AM
Subject: LF: Stainless steel versus
copper
Hi !
Is there any experience around
about using stainless steel wires for toploads or feeders versus copper
?
As to my knowledge there is a
certain amount of rf current penetrating into the conductor at 137/500 kHz.
Losses are expected to be high in lesser conductive materials at those
frequencies. Any ideas about the order of magnitude in current fed antennas
?
73 de wolf df2py /
di2bj
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