Amateur Radio Antennas

There are two aspects of amateur radio that are most important in having other hams copy our signals. These aspects are the amount of power output from the transmitter and the antenna used to send the signals into the air. This page briefly describes VHF and UHF antennas that might be used during emergency conditions. For larger views of the pictures shown below, click the pictures.

Rubber Ducks

Handheld transmitters (HT) come with antennas that are colloquially known as rubber ducks. These antennas are not very efficient, because they are short and don't have good grounding systems. It may be possible to replace the rubber duck that came with the HT with one that is longer and more efficient. HTs are frequently used for portable operations in which the person is walking or is inside buildings.

MagMounts

MagMount antennas have a powerful magnet fastened to the end of the antenna and can thus be mounted on top of a vehicle for mobile operation or on metal surfaces such as serving trays for fixed operation (for maximum efficiency, the metal surface should extend at least 1/4 wavelength in all directions from the antenna). These antennas are more efficient than rubber ducks.

I'm using a Larsen LM-MM mag mount and the Larsen LM-150 5/8 wavelength wire that I bought about 40 years ago. It has about a 3 db gain in the vertical plane over a 1/4 wavelength antenna. My antenna has a PL-259 UHF male connector. The antenna connects to the UHF connector on my mobile rig, and  and I use a UHF-BNC adapter to connect the antenna to my HT. CB World carries this antenna, and other ham radio stores may carry it, too.

 

Emergency Twin-Lead Antenna

An emergency antenna can quickly be made from twin-lead TV wire. It can be rolled into a small package that can easily be carried in your automobile glove compartment or in your emergency back pack. The following instructions, taken from http://www.qsl.net/wb3gck/jpole.htm, tell how to make a portable J-pole antenna for 2m.