The picture
above is a diagram of the old standby CLASSIC antennas....the
horizontal Dipole and the Inverted Vee. They are shown 'together" in
the drawing for ease of viewing on this page.
Additional notes of interest:
The horizontal
dipole and inverted V are shown superimposed on each other in the
drawing and without the feed line for clarity. It is assumed that
you understand that we are talking about 2 separate antennas in the
drawing and not one antenna with 2 bands fed with coax.
Feed
line (usually 50 ohms) is connected at
feedpoints, center conductor to one side,
the shield to the other side of antenna. The blue line in the drawing is the
example of a horizontal dipole. The copper
colored line is the inverted vee configuration. The inverted
vee is is just a lazy dipole that can't hold it's arms up and is
about 4 to 5% shorter in its total length. Both antennas can be
constructed just about anywhere using any type of wire you may have
and can be used with 50-75 ohm coax or open wire ladder line and a
tuner. When fed with open wire type feed, it becomes a multiband
antenna using a tuner. The use of an rf choke is recommended when
using coax feed!
The inverted V antenna more closely matchs the
50 ohm coax than does the standard horizontal dipole, so your swr
may be lower compared to a horizontal dipole fed with the same 50
ohm coax.
You could use the calculator to build a 75 or
80 meter dipole and then calculate an inverted vee for other
bands higher in frequency, suspended
under it as shown in the drawing above, from the same support
and feed both with the same line to xmtr. This is usually called a
"fan" dipole and works well when tuned for lowest SWR.
A little
experimentation may be required for adjustment of the SWR, tuning
the 75 meter dipole first for lowest SWR and then the inverted Vee/s
under it in a test, cut, test, cut fashion.
Download the Ground Plane/Dipole/Inverted V
Calculator by N2IMF
Courtesy of and
designed by
N2IMF
Joseph R Mielko
This
downloadable calculator will provide you with good starting
measurements for a basic ground plane, Inverted V or standard Dipole
antenna.
The
graphics below are "screen shots" taken from it. Non
functioning!
Basic
Ground Plane Calculator screen shot.
Dipole and Inverted V screen shot of
calculator.
This is a very simple
program to use and has a handy "Print" function and nice graphics
showing the basic layout of each antenna.
All you have to do is
run the program and input your design frequency in the white window
top left. Click "Calculate" and the length results are shown in
your choice of feet or inches.
You may be surprised at how
fast it works!
Download
instructions:
Download the zip file here and unzip
it to a folder of your choice and name on your computer.
It
is not a large file and should download quickly for dialup
users.
After the file unzips, open up the folder and
look for the "N2IMF antenna.exe file...double click it and the
program comes up! Enjoy!
Again, this
calculator is courtesy of N2IMF...Thanks Joe!
Here is another fine
Dipole and Ground Plane Calculator
Submitted by KD0MDI,
Mike
It is similar to the above
calculator but with some refinements that are very
handy!
Screen shot, non functioning! Shows
a 2 Meter ground plane designed for 146Mhz
Screen shot, non functioning
Same calculator setup
for calculating a dipole for 7.250Mhz
Download
the executable file for it here.
Courtesy of Mike,
KD0MDI
Thanks
Mike!