WB3AYW WIRE COLLINEAR FOR 2
An Improved Version
(See older version
3 element = 7 dBd
5 element = 9.4
10 element = 13 dBd
These Collinear antennas are " 4 " Megs wide and "must
be supported" at the top by a yard arm or tree
Building instructions for
the NEW WB3AYW Collinear Antenna
for Two Meters only 02/11/2014
the other bands are
NEVER PUT AN ANTENNA UP NEAR POWER
NO MATTER HOW CAREFUL YOU ARE
Coil example (see
Get water pipe, (CPVC) for hot/cold water at
your building supply store, it is tannish / white and 5/8 inch outside
Cut to 6 inches long for all coils assemblies. See photo above. Measure in on each end 2 1/4
inches and mark.
Measure the spacing between these marks and make
sure they are 1 1/2 inches apart.
Drill a 1/8 inch hole through each
mark all the way through the CPVC pipe.
Measure out 3/8 inches from
each hole and drill the same as the first set of holes. These are not as
critical as for measurement as the first set of holes you drilled.
There will be a modification later to these holes.
Cut your #14
SOLID insulated, TNN wire 14 inches long, one for each coil. Bare wire 1
1/2 inches then bend first end slightly after inserting it through
the first inside hole, then bend over more. Only 3 turns in between wire
ends on coil. Wire ends will come out on the same side of the coil
There should be 8 = inches of wire plus the two end
wires through the tubing.
Wind 8 1/2 inches of #14 solid wire on
coil form tightly and stop. If using the correct tubing (as I use), the
number of turns are 3 1/2 with insulation.
Pull coil wire towards
the other end of the CPVC form.
Feed the second end through the
inside hole on the other end and PULL TIGHT with Pliers!
Bend over like
you did on the 1st end; this keeps the coils the correct length.
you do not pull the coil wire tight it will vary the length and vary the
frequency / phasing, with up tilt. If wires are too long or too
short = down tilt, or if holes too wide = Down tilt, less capacitance,
Trim the wire ends, to the length of the outside
Make up all of your coil assembly's, 2, 4, 9 or whatever you
want. It takes 4 coil assemblies for a 5 element design.
outer holes of the CPVC assemblies; re-drill the hole at a slope next to
the wire ends so your radiating wire will slide through from the inside
out. See photo above.
Bare 3 inches and make
a 1/2 inch loop with your #12 stranded wire and solder the loop good, this
will have all of the weight of the antenna on it.
Measure and cut
top element to 37 1/2 inches length, this element is the only one, with
END EFFECT on it.
Bare about 3/8 inchs of the top element
wire and feed through the center (inside) of the CPVC and out
through the modified hole, and solder securely to the coil
Cut all other (#12) wire elements to 38 1/2 inches
Bare the #12 stranded wires (3/8 inch) on both ends.
through the center of the CPVC and out through the modified hole that you
re-drilled, making sure that it goes to the inner hole and solder to the
coil wire while making sure the radiator wire goes to the inner hole
before soldering! Thus keeping the length of the radiators
Solder all connections as you go.
Do the same to all
Cut a piece of CPVC 26 inches long.
Slide the 26
inch piece of CPVC over the lower element.
The matching section is
made from 300 OHM Ladder Line. I use the Wireman's Ladder Line.
Ladder Line to 18 1/2 inches then bare and bend the bottom to short
it. Solder the ends shorting it.
Measure up, 3 1/4 inches from the
short and bare the 2 wires of the Ladder Line about 1/2 inch.
the 50 OHM feed point APROXIMATELY.
Use 3 or 4 feet of RG8X
for a pigtail section. It will fit inside of the CPVC tubing with the
ladder line soldered to it. Seal all connections after tune up to prevent
moisture and Bees! Yes I said BEES!
Prepare your RG8X coax and
solder to ladder line feed point at the 3 1/4 inch point you
The length of the Ladder Line needs trimming to a length 16
Slide 26 inch piece of CPVC up over the lower
Solder the bottom radiator to the side with the coax
CENTER attached on the matching section.
RECHECK! Make sure
the side of the ladder line connection to the element is
Put antenna up horizontally about 4 feet above ground and
check VSWR, you should be lower in frequency than you want to be. Or the
ladder line is too short!
If the frequency is low, then slide the
26 inch piece of CPVC up or down over the matching network or lower
element and trim opposite side (short side) of the 300 ohm ladder
Cut 1/8 inch at the time, to bring it up to frequency
while putting the ladder line sleeve back on each time you check
VSWR. The sleeve will change the frequency about 2 Megs, Be careful as you
cut only 1/8 th of an inch at a time. Then recheck SWR.
the short side should now be about 16 3/4 inches long.
Seal all open
wire connections from moisture and Bees.
Seal up top and bottom of all
elements sleeves. The bottom sleeve needs to be weather tight at the top
to keep moisture out of the matching section and your coax.
like to build nests, so seal on both ends of all other coil
Leave the 1/8 inch holes open at the top and bottom, on the
side of the coils for water drainage.
The gain of the 5
element is about 9.7 dBd's (not dBi's) per my antenna program.
any problems or questions call me, 8AM till 4PM EST. 770 893 1216.
thanks to KK1CW for the original spreadsheet; without him this program
would not be possible!
Also see KK1CW for more
Leonard Shick WB3AYW