[Elecraft] G5RV

[George, W5YR]

Actually, Don and Bill, the G5RV is 1.5 wavelengths long on 20 meters, not
the 1.25 wave length of an EDZ. Varney designed it for 20 meters only and
used that length to (a) get some gain and pattern from the added wire and
(b) give the antenna about a 70 ohm driving point impedance as with a simple
half-wave dipole.

The twinlead is an electrical halfwave at the center of the 20 meter band so
it repeats the ~70 ohm impedance and makes for convenient connection to 75
ohm coax. That both reduces the length of coax required - expensive and
heavy on those immediate postwar days in England - and reduces the weight
the antenna had to carry at the center. Varney later suggested using
twinlead all the way from the antenna to the tuner - whatever length was
needed.

The antenna does not have the gain of an EDZ since it is a bit too long. If
Varney had used 88 ft instead of 102 ft, he would have had an EDZ but with
an awkward driving point impedance to deal with.

The G5RV performs as any 102 ft length of wire. There is nothing magic about
that length other than on 20 meters where it is 1.5 wavelengths and presents
the pattern and input impedance Varney desired. Don is very much right on
that score. A lot has been made of the "magic" of the G5RV that is
undeserved. Nowadays any antenna 102 ft long is christened a "G5RV" and the
marketers make much of its alleged properties.

And that is all *I* will say on that subject!  [g]

73, George W5YR
Fairview, TX
w5yr@att.net
http://www.w5yr.com


----- Original Message ----- 
From: "Don Wilhelm" <w3fpr@isp.com>
To: <Able2fly@aol.com>; <elecraft@mailman.qth.net>
Sent: Thursday, March 25, 2004 3:53 PM
Subject: Re: [Elecraft] G5RV


> Bill,
> The G5RV as originally designed is a double extended Zepp cut for 20
meters.
> The 300 ohm feedline was cut to a length where the impedance was at 50 (or
> is it 75? - no real matter) ohms, and the rest of the run was made with
> coax.  A great antenna for 20 meters.
>
> Now somewhere someone discovered that this antenna can tune multiple
bands -
> guess what? any length antenna can tune multiple bands too.  The modern
day
> 'G5RV' being sold is a far cry extension of the original - the only thing
> left is the length of the flattop and there is no real magic in that
length
> IMHO.
>
> And that is all I will say on that subject.  Check L B Cebik's website
> www.cebik.com for a detailed analysis.  Like all antennas, they have their
> beleivers and non-believers.
>
> 73,
> Don W3FPR