Date: Sat, 28 Sep 1996 16:26:26 PST
From: wb2vuo@juno.com (William K Hibbert)
To: qrp-l@Lehigh.EDU
Subject: [644] The Wye, an Inverted Wire G.P.
Message-ID: <19960928.163230.4335.0.wb2vuo@juno.com>

        The "Wye", a 3-Wire Ground-Plane Antenna

So, here you sit. You just got a new radio, or the 
urge to run on a band that you haven't used your 
old radio on before. So you grab your "MEGA-RADIO" 
catalog, open it to the "ANTENNA" section, and just 
about CHOKE when you see the prices on the antlers 
for the band of interest...

So, what is the cheap, er-r-r, frugal Ham to do?  
How about a Ground-Plane antenna.  "Sure", you say, 
"Aluminum tubing just grows on the trees
around
here..." Maybe not, but good old #14 house wire is 
inexpensive, and readily available.  What you need to 
do is to simplify the Ground-Plane (GP) antenna.

Looking at the GP, it is basically a 1/4-wave radiator, 
working against a "ground-plane". the ground-plane is 
an elevated counterpoise, which provides an electrical 
"image" of the radiating element.  The simplest form of 
the GP would be a vertical element, with a 1/4-wave wire 
extending out at a 90-degree angle from the feedpoint.  
This used to be shown in the "Radio Amateur's Handbook" 
as the "30 Up & 30 Out".  It was a 30 foot vertical, 
mounted on the roof, with a single wire extending out 30 
feet, and was fed with 300-ohm ribbon, or ladder line.  
Despite the simplicity, this is an effective antler, and 
is still a viable one today.

The next step up is the "Wye", a 3-wire GP.  In this 
configuration, the radiating element is hung from the 
eaves, (if high enough), or a tree branch.  The radials 
consist of 2 wires connected to the braid on the coax 
cable, and pulled out & down, forming an upside-down "Y".  
In its simplest version, on VHF, the wires can be solid 
#10 or #12, with the wires soldered directly to a 
chassis-type coax connector.  Zack, KH6CP/1 had just such 
an antenna in "QST" in 1992 or 1993, but I can't find the 
exact month right now.  In "Ham Radio", back about 1985, 
W1JR had a 20 Meter version published, and Doug, W1FB has 
a 30 Meter version in his "Antenna Notebook".  Nothing 
really new, but a good idea is ALWAYS worth repeating.

                          CHARTS & FORMULAS

You can't have anything on antlers without a chart or 3, 
and formulas are needed to beef up the information,  so, 
here are some dimensions and formulas for the "Wye", for 
40 - 2 Meters:

        Radiator(ft) = 234/F(Mhz)       Radial(ft) = 246/F(Mhz)

        Frequency               Radiator                Radial
         7.1 Mhz                33'  0"                 34'  8"
        10.1 Mhz                23'  2"                 24'  5"
        14.2 Mhz                16'  6"                 17'  4"
        18.1 Mhz                12' 11"                 13'  7"
        21.2 Mhz                11'  0"                 11'  7"
        24.9 Mhz                 9'  5"                  9' 11"
        28.4 Mhz                 8'  4"                  8'  8"
        29.4 Mhz                 8'  0"                  8'  5"
        50.3 Mhz                  55.8"                   58.6"
        52.5 Mhz                  53.5"                   56.2"
       146.0 Mhz                  19.2"                   20.2"

72/73, Keith, WB2VUO, QRP-L #582
Trustee, KB2YTW/B 10 Mtr Beacon (28.2860 MHz)
"In the Depths of the Great Bergen Swamp...FN13ac"


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