The stainless steel used in extendable whip antennas is typically
type 301 or 304, both of which have a relative permeability of 1.05
or less ... which means they are essentially non-magnetic and don't
have much more skin effect than copper or aluminum.? I just used
EZNEC Pro v7 with NEC5 (which does model skin effect) to model a
full size ground plane antenna for 20m using 3/8 inch diameter
tubing (similar to the 17 foot extendable whips) and the difference
in performance between stainless steel and copper taking into
account the difference in both resistivity and permeability is about
0.16 dB.? Even if the entire 17 foot whip was only 0.1 inches in
diameter the difference is only 0.4 dB.
So no ... it is not a big deal.? The additional loss is negligible.?
The loss in any of these short base loaded alternatives is FAR
greater.
By the way, I also generated a model as close to what I think an AX1
looks like as I could get.? With a 13 foot counterpoise wire EZNEC
said there is 16 times (!!) more radiated power from the
counterpoise wire than there is from the 4 foot whip.
Dave?? AB7E
On 3/26/2025 6:50 AM, kb1gmx via
groups.io wrote:
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?
Generally not a fan of stainless whips, the stainless is
strong but has
high resistance and losses at RF.? Depite that, they are
handy and I
have a few good ones from Buddypole.
?
--
Allison
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