The following instructions will enable you to build a quarter-wave ground plane antenna with which you will be able to receive and send radio signals better than you can with the "rubber-ducky" or telescopic whip antennas usually supplied with scanners and other low cost receivers.

This antenna is tuned for the 2-meter ham band (144-148 MHz) but will give very good results for other similar frequencies.

You will need:

• 5 conductors, each 19 inches long. Stiff copper or steel wire, or even coat hangers will do the job.
• 1 SO-239 chassis mount coax connector from Radio Shack or your neighborhood electronics store (actually a female BNC connector would be even better).
• 1 length (no more than 50 feet) of RG-58U coax cable.
• 4 nuts, bolts and solder tags.

Construction

• The SO-239 connector has four mounting holes for bolting it to a chassis. Using the four nuts and bolts, mount the solder tags on these holes.
• Solder four of the pieces of wire to the four solder tags. The four wires will spread out perpendicular to each other to form a horizontal "ground plane". To improve performance, you can bend these wires down at 45 degrees to the horizontal. If you are using steel conductors you may have difficulty soldering directly to the tags. If so, bind the steel conductor to the solder tag using copper wire and, using a high power soldering iron, seal the joint with solder.
• Solder the fourth wire to the central conductor tag of the SO-239 connector so that it projects vertically with respect to the other wires.
• Connect the RG-58U coax to the SO-239 connector and to your radio, and mount the antenna as high as possible - preferably outdoors.