Vertical Half-Rhombic
The vertical half-rhombic antenna is
used as a field expedient antenna. It is effective at lower frequencies,
however it's peak performance comes at higher frequencies.
To construct
a vertical half-rhombic you will need the following:
- 200 feet of WD-1/TT or WD-1A/TT
- Electrical Tape
- 400-600 ohms terminating resistor
- Insulators or material to construct field expedient insulators
- Radio set
- Knife
- Suspension line
- Measuring device
- Compass
- Signal Operating Instructions (SOI) with frequency and call signs
- Large open area
To erect the antenna follow these steps:
- Determine azimuth from the transmitting radio to the receiving radio.
- Measure 100 feet of wire.
- Bend the wire in half to find the apex point for the connection of the insulator.
- Connect insulator at the apex point and at both ends of the wire.
- Tie a halyard to the insulator at the apex point. the suspend the apex between 20 and 30 feet above the ground.
(This can be achieved using a tree, camouflage poles, or whatever is handy)- Separate the two ends of the wire, ensuring that you keep them on line with the desired transmission azimuth.
- Connect a wire to the ground side of the insulators at both ends of the wire, and stake them down to the ground.
- Install a counterpoise.
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- Run a wire from the ground side of the insulators at the ends of the antenna wire.
(Ensure that the counterpoise wire is directly under the antenna and one foot off the ground.)- Attach another piece of wire from the near end ground stake to a screw on the radio set case.
(For a uni-directional antenna attach a 600 ohm, 1 or 2 watt resistor across the far end insulator. for a bi-directional antenna leave the resistor off.)
- Split the WD-1 at the near end, attach one piece to the bottom end of a whip antenna and screw it into the antenna connector on the RT. Connect the piece to a screw on the RT case for a ground.
