Posted by
N2EY on
May 17, 2007; 11:18am
URL: http://elecraft.85.s1.nabble.com/OT-G5RV-antenna-baluns-tp447606p447614.html
In a message dated 5/16/07 10:17:09 PM Eastern Daylight Time,
[hidden email]
writes:
> I have G5RV's original article introducing the antenna.
> He specifically states that it is a 20M antenna, and yet it's
> now somehow become a do-all-bands wonder ... an almost
> "cult" thing.
In all the G5RV articles I've read, including the original, it's a multiband
antenna. It was specifically designed that way by G5RV.
What's special about the G5RV is that if it is properly built and installed,
it will present a low (but not 1:1) SWR and good efficiency on the non-WARC
bands.
And it's simple.
> The same thing happened with the single-wire fed
> Windom years ago. EVERYONE had them.
>
That antenna goes back to the 1920s. The "Windoms" we have today are really
off-center-fed (OCF) dipoles.
> Why would one want to clobber up an open-wire fed dipole?
> The G5RV version requires a tuner when used on bands other
> than 20M, so why not bring the open-wire to the tuner and
> dispense with the open-wire-to-coax transition kludge hanging
> outside in the sky? It's a simple application made difficult.
No, it isn't.
The reason for the popularity of G5RVs and OCFs is this:
Properly made and installed, they are capable of low SWR (not unity) on
multiple bands, and they wind up with a coax feeder of random length coming into
the shack.
While a tuner may be needed to get 1:1 SWR at the rig, the tuner need not be
balanced, nor does it need to have a wide matching range. A simple, low cost
tuner can do the job of tuning out the relatively-small mismatch.
OTOH, if you simply put up the classic dipole-fed-with-ladder-line and don't
concern yourself too much with lengths of dipole and feeder, the result can be
a wide range of impedances at the shack end of the line. So you need a much
more expensive tuner to get the system to work efficiently.
All three systems will work well if done right. After all, they're all just
dipoles with different feed systems. The question is, what resources are
available?
73 de Jim, N2EY
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