Antenna efficiency is reduced by power lost to heat radiation, either
from conductor resistance or dielectric loss in nonconducting
components of the antenna.
Antenna SYSTEM efficiency, as read, needs to be defined for the stated
figure, as the diminishing might include coax loss, ground loss, or
even radiation/scattering in unwanted directions.
73, Guy.
----- Original Message -----
From: "Jon Ogden" <na9d@speakeasy.net>
To: "Pete Smith" <n4zr@contesting.com>; <towertalk@contesting.com>
Sent: Thursday, January 23, 2003 8:04 PM
Subject: Re: [Towertalk] Efficiency of antennas
> I'd agree with that.
>
> It may also depend on how they define the terms. Every antenna has
a figure
> for "radiation" resistance. Could they be basing it on that? Or is
it the
> power lost in the loaded coils.....
>
> Figures lie and liars figure!
>
> 73,
>
> Jon
> NA9D
>
> on 1/23/03 4:45 PM, Pete Smith at n4zr@contesting.com wrote:
>
> > I've seen some fairly interesting claims recently for the
efficiency of
> > yagis with coil loading. I'm not quite sure what efficiency means
in this
> > context -- is it simply the percentage of the driving power that
is
> > actually available to be coupled to what we used to call the
ether? If so,
> > is it just another way of expressing the amount of loss in loading
> > coils? If an antenna manufacturer claims 90 percent efficiency,
is that
> > just another way of saying that 1/10 of the applied power is being
> > dissipated in heat?
>
> -------------------------------------
> Jon Ogden
> NA9D (ex: KE9NA)
>
> Citizen of the People's Democratic Republik of Illinois
>
> Life Member: ARRL, NRA
> Member: AMSAT, DXCC
>
> http://www.qsl.net/na9d <- Updated on 1/22/03!!!
>
> "A life lived in fear is a life half lived."
>
>
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