[Rover] RE: WA5VJB Cheap Yagis ? ? ?

[Phil Lefever]

At 04:02 PM 9/5/02, you wrote:
>From: "Phil Lefever" <plefever@isd.net>
>
> > I'd recommend against using Stainless Steel for antenna elements! The
> > RF resistance is too high and it will cause a measurable loss of antenna
> > gain.
>
>
>
>Mike wrote
>
>Now wait a minute ... my six meter mono-band whip on the car is stainless,
>the whip portion of my Larsen, NMO270 is stainless, most mobile antennas I
>know of are stainless.
>
>What's the difference?

Many of the Larsen antennas use what they call KULROD plated whips
which is a stainless steel whip but it is plated with copper under
the black finish. Other mobile antennas that do have non plated
stainless whips just aren't worried about the couple db loss that
the RF resistance causes. We use beam antennas for weak signal
work because every DB counts so why choose a material that is known
to cause loss. A mobile antennas primary goal isn't to maximize
gain/efficiency.

Another issue is that mobile antennas have to deal with elements
(like road salt) that beams never usually see.

I would also venture a guess that high RF resistance in the parasitic
elements of a beam will degrade performance more then a simple vertical
due to issues with damaging the "Q" of the system. There are also more
elements and the loss is cumulative to a degree. How many commercial
beam antennas are made with either steel or stainless steel elements?

73

Phil
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Phil Lefever - KB=D8NES			Twin Cities Repeater Club
kb0nes@tcrc.org			Tech Team Co-Chairman
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