Amateur Radio WB3GCK The Twinlead J-Pole
Craig LaBarge, WB3GCK

In an emergency situation, it is often necessary to squeeze every bit of performance possible out of a 2 meter HT. One way to do that is to replace that little rubber duck antenna with the ever-popular Twinlead J-Pole. This simple antenna lends itself well to emergency use or as a portable antenna for hotel room operations while traveling.

There are several features which make the ubiquitous Twinlead J-Pole antenna a good addition to your emergency grab-n-go kit. When rolled up, it is an extremely compact, pocket-sized antenna. In use, it makes for a very effective antenna and provides about 3 db of gain with a low take-off angle. In fact, when used on your HT, it will dramatically out-perform your rubber duckie. And finally, it can be built in no time flat for a few dollars of readily available materials.

Technically-speaking, the J-Pole is an end-fed, halfwave antenna with a quarterwave matching section to allow feeding with 50-ohm coax. Being a halfwave antenna, it is not dependent on a ground or radials for proper performance. That's also a plus for portable operation.

Here's what you'll need to build one for the 2 meter band:

Here's how you build it:

Figure 1

That's about all there is to it. To facilitate hanging, punch a small hole in the top of the antenna. Use monofilament fishing line or other non-conductive line through the hole for hanging. The J-Pole is very broad-banded, so it shouldn't require any tuning. (An SWR check, however, is recommended.) Just unroll it, hang it up, and communicate.


© 1998 Craig A. LaBarge

Back to Homepage