> > Think about it this way. If you made a dipole, would you
> > cut one side 5% longer than the other?
>
> Maybe, if you had a reason for offset feed... but most offset
> Dipoles are not 5% different. I thought the subject was about
> 1/4 wave ground planes and not dipoles... they are not the
> same animal.
That's my point. If there was a specific reason for making one side of the
dipole exactly 5% longer (based on some pre-determination such as a computer
model), then fine. But to generically say that all dipoles need to be cut
with one side 5% longer than the other carries no more engineering support
than saying that's how you should cut the radials on all groundplane
antennas.
I wasn't saying that there's never a reason to un-balance a balanced
antenna. I was saying that a generic rule like "make one side 5% longer in
all cases" lacks merit.
Kinda along the same lines as "always make the cable from the connector on
the transmitter to the connector on the duplexer an even half-wave".
As far as an elevated groundplane with a small number of radials, it does,
in fact, behave more like a dipole than a ground-mounted ("earthed")
antenna, which is why I used the dipole as a simile in my rhetorical
question.
> > Why not make the vertical radiator 5% longer, and leave
> > the radials exactly a quarter-wave, thereby saving on
> > materials?
>
> Because a quarter wave ground plane doesn't work well with a
> beta match that way.
Don't necessarily need a beta match for a groundplane. It can be regular
series-fed, gamma, shunt, whatever.
> I'll email you direct...
> cheers,
> skipp
I'll be on pins and needles! :-)
Later.
--- Jeff WN3A
