Super Antennas
By Vern Wright W6MMA
YAGI Portable Sys.
3EL. 6 Band YAGI
20, 15, 17, 12, 10, 6M
Model YP-3
Antenna Modeling
By Mike Staal of M2
THE SUPERANTENNA YP3 6
BAND
3 ELEMENT YAGI
by
Vern,
W6MMA
Congratulations. You have just received a light-weight, extremely flexible beam
antenna designed for field applications by the QRP operator and others. The antenna provides forward gain and directivity on all band 20M through 8M using and
ingenious combination
of
parts that you adjust
in
the field with almost no tools.
When placed on a common push-up or similar mast at least 20 feet tall, the antenna will provide the benefits
of
directional reception and transmission. Yet you
may carry the antenna
in
a 3 foot long bag with great ease as you move from
home to field and back again.
In
operation, the antenna expands to a maximum
side to side width
of
about 220 inches and a maximum length
of
less than 120
inches. The estimated power limit
of
the antenna is 500 Watts.
WHAT
IS
THE SUPERANTNENNA FIELD YAGI?
The field Yagi is a 3 element Yagi optimized within its design for use on a wide
range
of
frequencies. The Yagi 3 element design provides wide bandwidth
on
each band for each field adjustments. You only need to set and measure the ele-
ment lengths and coils according to the instructions for each band You may even
vary the recommended dimensions for special circumstances and the instructions
will provide you with some guidelines.
For 8 meter operation, the boom must be shortened and the elements greatly re-
duced
in
length but it is now a full size Yagi with good gain and FIB on the bottom
of
the band 50.0 to 50.5 mHz.
CW
operation is 50.0 to 50.100 normally. 50.110 is
the international SSB and
CW
calling frequency. 50.125 is the beginning
of
the
stateside phone band. Normally SSb contacts inside the USA are not done below
50.125. The 8m beacon band is 50.0 to 50.080.
On 10 meters you have a full size yagi that covers the bottom 1 mHz with one
setting. Boom length is set to maximum and no coils are required. Gain and FIB
are excellent.
On 17 and 12 meters mid element coils are used to resonate the elements and
the antenna will cover the full amateur band. You will experience good gain and
FIB on both bands.
20 and 15 meters are much wider bands, therefore the coil loaded element re-
quire two settings per band. The gain and FIB on 15m is close to that
of
a full
size Yagi. On 20m the reduced size
of
the antenna for portable work will provide
good directivity and FIB offering improved communications over a dipole at the
same height.
YP3 SUPERANTENNA ASSEMBLY DETAILS
9-9-08
TOOLS REQUIRED:
Measuring
tape, 1/2
nut
driver;
end
wrench
or
socket.
Prior
to
assembly
chose
the
band
you
intend
to
operate.
1.
Layout
the boom sections and assemble using the DIMENSION sheet as a
guide for position.
2.
Layout
the elements sections by length and position as shown the DIMENSION
sheet.
Now begin threading the element sections together. The large coils are used
only on 20M. Use a tape measure to set the exposed length
of
each element
section. TIP: If you plan on using the same band over and over, mark the
dimension with a permanent felt pen marker and note the band (20m) next to
the marks. This will really speed up reassembly at the next site.
3.
Continue assembling the sections until you get to the 1/4" diameter rod tips. Use
a tape measure and set each tip pair to the correct length.
4.
The Director element halves and the Reflector element halves simply screw into
the center mounting block at each end
of
the boom. Be careful to place the
reflector elements at the correct spacing to the driven element.
5.
The driven element Matching device is a HAIRPIN. Each 1/8" brass hairpin rod
has a 3/8' ring lug at one end. Insert the threaded butt of each Driven element
half through the ring lug and then screw it into the center feed block. Align the
rods parallel with the boom and install the shorting rod
on
the two hairpin rods.
Set it to the proper length for the band you have chosen.
6.
Plug
in
the banana jack to BNC adapter, attach your feed line and mount the
antenna on an appropriate mast as high as possible. If the antenna is placed
15 to 20 feet above ground, the best match should be very close to center
of
the
band or band segment you have chosen. Small adjustments to the driven
element tips should bring the match to the desired frequency.
7.
If large frequency shifts are required, find the frequency where the antenna is
working properly like 28.4 mHz. Divide that frequency by the new frequency.
28.4/29.4
= .966. Measure the element half length, say 98", and multiply
98x .966
= 94.668 (round off to 94.75) and adjust each element tip to achieve
the new element half length. Do this to all 3 elements. Make small
improvements
in
frequency and VSWR by adjusting the Driven Element tips
slightly.
Don't be too concerned about a VSWR
of
1.5:1 or less. Your radio should handle
this with ease and spend time on the air having fun
...
enjoy!
Loading...