The developer of the G5RV basically states that it is optimized for 20M,
thus typically having a low SWR of 1.8:1 on that band. Other bands the G5RV
will have a higher SWR in the range of 5:1. Thus on some frequencies the
G5RV may be too reactive for the limited range of many internal tuners.
Interesting enough, the length of the G5RV is 51 ft on each side of center
for a total of 102 ft. overall. Then add the 31 ft of 450 ohm ladder line.
Looking at the configuration we see it is basically two inverted L's
oriented back to back with the long portion of the L being the flat top 51
ft sections and the short part of the L being each side of the 30 ft of
ladder line. To sum it up, a dipole with reverse drooping ends for a total
length of 133 ft. Just the right length of most 80M antennas. However with
the feedline length of 31 ft, considering velocity factor, it is
approximately 1/2 wave on 20M. Thus the flat top ends each become 3/4
wavelength on 20M for 1.5 wavelengths overall. The impedance at the center
feedpoint is ~90 ohms, depending on height above ground. With a 1/2
wavelength transmission line being fed from a 1:1 current balun this load is
seen by the transmitter with the SWR on the coaxial segment being
approximately 1.8:1.
While some claim that the G5RV is an all band antenna, we find in reality it
is a non resonant dipole fed with a section of ladder line from a 1:1
current balun. Thus a wide range tuner is required to match this antenna on
all HF bands where the antenna is approaching 1/2 wavelength or more.
You are correct, the configuration you have is certainly not a G5RV by any
degree of imagination.
73
Bob, K4TAX
----- Original Message -----
From: "Wade Staggs" <tvman1954@gmail.com>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Sunday, September 14, 2014 9:09 PM
Subject: Re: [TenTec] Antenna names
*Running 126 feet of wire... 63 feet in each direction... Center fed with
450 ohm Window Line. It is most assuredly Not a G5RV. But my friends keep
wanting to call it a G5RV. We can work 80 thru 6 meters with a good manual
tuner. Is it the best antenna in the World? Of course not...... But at
this
Rental Property with some restrictions, we can talk and hear about the
same
as others using Fan Dipoles and Dedicated to the Single Band Dipoles.
Everything in life is a compromise. Can I unbalance the antenna and offset
the Window Line an inch from the dead center and call it a Windom? This
would clear up everyone's insistence that my antenna is a G5RV..... Just
Joking Folks....*
*
73 from Wade/KJ4WS*
On Sun, Sep 14, 2014 at 2:41 PM, Ken Brown <ken.d.brown@hawaiiantel.net>
wrote:
The Zepp was a one sided antenna, with a quarter wavelength openwire
feedline to a halfwave wire. ....
Hams are funny about naming antennas. For example, a Zepp antenna may
have
been clearly defined as above, but then people make modifications that
diverge so much from the original meaning of the name it makes no sense
to
keep using that name. Make it into a dipole, and call it a "Double Zepp."
There is no way a Double Zepp could ever be used the way a "real Zepp"
was
used on a Zeppelin....
Or make the horizontal wire longer, and call it an "Extended Zepp." But
then it is not the length it needs to be a normal Zepp. So why keep
calling
it a Zepp?
Then there is the G5RV antenna. The "inventor" G5RV said there is no such
thing. He built a dipole and experimented with various lengths of ladder
line and coax, to try to find a combination that worked good on multiple
bands. He said it was just a dipole, but the ham community called it a
G5RV. Now there are hams who claim that a specific length dipole, with
specific lengths of ladder line and coax feeding it are "genuine G5RV
antennas" and the anything else is not. Other hams think that any dipole
fed with ladder line is a G5RV.
DE N6KB
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