A SIMPLE ANTENNA SOLUTION FOR 20-METER FIELD OPERATIONS

An antenna I have had success using for QRP field operations is a simple 20 meter quarter wave vertical using number 18 wire.

The supporting pole is a 20-foot fiberglass unit that I bought from Worldradio for $20. The weight of the pole is 1.7 pounds and the weight of the antenna is 1.28 pounds with six radials. That doesn’t include the feedline.

The weight of the antenna could be reduced slightly by using a BNC connector, smaller alligator clips and smaller wire. The radials are approximately a quarter wave long and connected by alligator clips to the shield side of the coax connector.

These are just stretched out on the ground. The efficiency of a vertical antenna is mostly dependent on the amount of ground resistance.

Vertical antennas can be notoriously inefficient when working against a poor ground. Efficiency is defined as radiated power divided by the amount of power applied.

Ground resistance is reduced by having a good ground plane for the antenna. The more radials you have the more efficient the antenna will be.

I placed a tight loop on one end of the wire and a SO-239 connector on the other. The loop is placed on the top of the fiberglass pole and the wire hangs down the pole when extended.

On the shield side of the SO-239 I placed a loop of wire that keeps the wire from flapping around and also lets the radials be connected using the alligator clips. I used insulated wire because it is easier to untangle.

As you can see, there is nothing original about the antenna. It is very important that the antenna have a good ground plane.
A one wire ground plane is not very efficient. For QRP work, the antenna should have as many radials as one can tolerate.

With six radials and running two watts, this antenna seems to work well.

If this is too much antenna for backpacking, one might try a dipole antenna. But then the radiation pattern will be different.
I feel like I am preaching to the choir, but this antenna is easy for me to carry on my bicycle.

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Jim Varner, AE6N, is a QRPer, outdoorsman and bicyclist living in Lake Havasu City, AZ. He has been a radio amateur since 1947.