I would expect the shorter antenna to have a higher current
maximum due to a lower radiation resistance. The longer
antenna should have a lower current maximum, but the current
will be distributed over a larger area. Thus I would expect the
longer antenna to have slightly higher directivity and probably
higher efficiency due to the higher radiation resistance (lower
average I -> lower I^2*R losses). These differences in gain and
efficiency between the 88' antenna and the 100' antenna should
be fairly small, however, provided that you can deliver power
efficiently to the feedpoint of the shorter antenna, which as
Gary, Tom, and others have pointed out can be no small
problem.
73 de Mike, W4EF.........................................
----- Original Message -----
From: "Gary Schafer" <garyschafer@comcast.net>
To: "Joe Subich, K4IK" <k4ik@subich.com>
>
> Joe Subich, K4IK wrote:
> >
> > I strongly disagree. L.B. bases his recommendation for the 88'
> > dipole on only one factor, the ability to maintain a broadside
> > lobe between 3.5 and 14.5 MHz. That's not the only thing to
> > consider.
> >
> > 1) The longer antenna will have a higher current, particularly
> > at the current maxima. Higher current => more radiation =>
> > more gain/higher efficiency.
> >
>
>
> A short antenna will radiate just as well as a long antenna. Its length
> makes no difference in the amount of power radiated.
>
> The only thing that changes the gain in a particular direction is
> changing the pattern of the antenna or changing its efficiency.
> Its efficiency isn't going to change very much by changing its length
> 10% or so.
> Getting power to the antenna can be a determining problem though.
>
> 73
> Gary K4FMX
>
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