THE ZZ "WAVE NET" ANTENNA BY
VE6VIS
A DUAL LOOP
- 80 AND 40 METER HF WIRE ANTENNA
PROJECT
When you
can't go out, you've gotta go up!
Updated
Sept, 2006 with new information
Do
you want a full wave loop for 80 and 40 meters but have only a city
lot?
Got a 64 foot tower or equivilant support with enough space
at the top to add some insulators and a little time plus some
wire? Got some 16 foot supports for each end? Want a great
signal on both bands?
Then try this antenna project submitted by
Mike Wigle, VE6VIS and prepare for loads of
fun!
This antenna is the
result of many hours of thinking and tweeking and trial and error
and starting again and again. It was worth all the effort as I have
come up with a very fine antenna that should make the lives of many
hams much better by using a loop antenna instead of the inverted V's
that so many of us use now.
The antenna is
basically a full wave 80 meter loop on top and a 40 meter loop on
the bottom all supported from a 64 foot center support, namely my
tower. They are both fed from the
center feed point with one length of 50 ohm coax. No tuner is
required. Use the standard formula: 1005/freqmhz, (your center
frequency), for total length of each "loop". Adjust for best swr by
raising or lowering feed point from top of antenna. It requires the
64 foot center support (tower or mast) and 2, 16 foot end supports.
VE6VIS
Editors
note:
Another way of
looking at this project is that two Delta loops, one for each band
and squashed to fit the space on the tower and your lot are
paralleled and fed with one length of
coax.
The ZZ Wave Net is a revolutionary
new design in HF
antenna's.
The ZZ Wave Net starts with
the same principal as a
dipole
antenna bent into an inverted V.

Next, the ZZ is a folded dipole bent
into an inverted V
loop!!!

Next we pull the ends of the folded dipole and
separate
the middle as in the drawing above.
This allows us
to install the antenna in a city lot and still
keep the overall
performance of a full wave loop antenna!
Then we add the 40 meter ZZ loop under the 80 and
we have the ZZ Wave Net, a dual 40 & 80 meter full wave loop
antenna!
Below is how it looks installed on a 64 foot
tower with 16 foot
end supports on your city
lot.


Dimensions:
(80 meter on
top, 40 meter on bottom)
80
meter apex to end 70
feet
80 meter end to feedpoint 65 feet
40 meter
feedpoint to end 36 feet
40 meter end to
bottom 34 feet
Apex to
feedpoint 24 feet
Feedpoint
to bottom 12 feet
Feedpoint is 4:1 balun
Both
loops feed from this point
End support to end
support 105
feet
Construction:
Measure wire and lay out at base
of tower.
Attach 1 litre bottle half full of water to the bottom
wire about 12 feet from the ends on both sides of antenna.This is so
the wires don't twist and so the antenna will have greater tuning
range.
Attach apex of antenna to top of tower on a standoff and
preferably with a rope and pulley system.
Pull feedpoint up to 24
feet below apex.
Pull ends out to look like the
picture.
Tuning
Instructions
The wire length is the first thing to get
right.
Use the usual method of (low longer) ie: if the swr is
higher on the low freq then make the antenna longer and if the swr
is higher on the high side then make the antenna shorter.
Then
the next step is the distance between the wires.
The distance
between the feed point and the apex is 24 feet @ 80 meters.
The
final tuning is done by tightening the wires from the
ends.

Loose ZZ

Tight ZZ
So you get the
antenna pulled out to look like the
picture above, then you
can adjust the swr by tightening and
loosening the wires. You
will see a great range of
tuning here which is why this antenna
design is so
easy to tune.
The best way to do this is to
mark the place where the
rope meets the tie off point. ( this is
the trick for
tuning this antenna) So, if for instance you have
the
rope tied off to a tree. You mark the point where the
rope
meets the tree by tying a piece of string onto the rope.
This is
your marker.
Check the swr. Then loosen the rope so the
marker is
about a foot from the tree, Then check the match again.
You
will notice that it has changed. Now you can tune to
a
point where the match is lowest.
Shorten and lengthen the
wire to provide the lowest swr
within the range that you
can loosen and tighten the wires
for lowest swr and you will
find that this antenna will
match right down flat at the
operating freq of your choice :)
Also you may find that the
antenna wants to be shorter
than the normal calculation.This
depends on a number of factors
like reflections and hieght above
ground.
Tune the 80 meter length first and then the
40.
This antenna also works as an 80 and 20 or 80 stand
alone,
40 stand alone, 40 and 20 etc.
Have fun :) Mike
Wigle, VE6VIS
Russian Translation here
by
UA3TJC