Two Meter Extended Double Zepp Antenna

Two Meter Extended Double Zepp Antenna

The materials list is as follows.

2 ea 10-foot (3.04m) lengths of 1/2 in. (1.27cm) electrical conduit.
1 ea 3 x 7 (7.62x17.78cm) sheet metal splice for 2x4 (5.08x10.16cm).
1 ea SO-239 chassis connector - open one mounting hole with a 5/32 (4mm) drill and solder in a 4 in (10.16cm) wire to center conductor.
3 ea #8 x 1/2" self-drilling sheet metal screws.
4 ea #8x 1/2" sheet metal screws
1 ea dowel 5/8" (63mm) diameter, 12" (30.48cm) long. Wood is ok, but fiberglass or plastic would be better. (I used PVC over the outside)
1 ea +/- 24in. (60.96cm) long wire, #8-12 wire size for phasing hairpin.

Putting A and B together
Force dowel C into A up to the mark. Measure 3/4inches (1.91cm.) from the end of the dowel and drill a 1/8inch (.32cm) hole. Screw in a #8-1/2 inch (1.27cm) sheet metal screw. Force the other end of the dowel up to the mark. Be sure that there is a 1/2-inch (1.27cm) space between A and B. Exactly opposite the screw in A measure 3/4inch (1.91cm.) up on B and drill another 1/8inch (.32cm) hole. Screw in another #8-1/2 inch (1.27cm) sheet metal screw. These two screws hold A and B together and provide for holding the hairpin in place.

My Modification,

Keep (A) as one complete 10’ piece

Once (B) is cut to the 48.75" length then cut the J-drive out of the remainder of (B)

I cut the J-drive 23.75" plus the length of your splice block. (I didn’t use the 3x7 I used a 2x4 metal electrical receptacle cover).

At the top of the J-drive I also used a piece of Plexiglas to maintain the spacing at the top. (If you use the 3x7 Splice block at the bottom, you may not need the top support).

For (C) I used a piece of pvc pipe that fit snugly over the ½" EMT conduit.

For the phasing hairpin I used #8 copper ground wire

For attaching to a mast pole the extra length on the bottom of (A) works real good to stabilize the antenna, usually you may only need 2-3 good heavy duty hose clamps to secure the whole antenna to the mast.

I used a 1" spacing between the elements. It doesn’t matter either way the important part is getting the hairpin in the right place.

SPECIFICATIONS

Frequency, MHz 135-160
SWR 1.2:1 Typical
2:1 Bandwidth, MHz >3
Gain, dB 7.0
Power Rating, Watts FM – 200+
Radiation Angle, Deg. - 7
Horizontal Radiation Pattern, Degrees - 360