About Ham Radio Antennas

Since the early 1900s, ham radio operators have been around furthering both radio technology through personal innovation as well as providing public service transmissions and serving as qualified operators for the military in time of war. As technology has progressed, the ham operator's equipment from the transceiver to radio antenna has evolved to keep pace.

History

Ham radio is the nickname for amateur radio enthusiasts worldwide. Ham radio operators use a number of types of communications gear to pass communications to other operators for public service announcements, training and other not-for-profit reasons. As technology has evolved, so has the ham radio operators equipment to include the types of antenna used based on the radio frequency being broadcast.

Function

A ham radio shack consists of a number of pieces of equipment to include: the transceiver; a computer; mobile/base transceiver or handheld radio; microphones, keys and headphones; antennas; and cables and feed lines. Even with today's technology, most ham radio operators will require several antennas dependent on the radio frequencies transmitted. Depending on the the type of antenna, the ham radio antenna can be used for signal receipt or transmission.

Types

There are a number of types of antenna for the ham radio operator to use dependent on range and type of communication desired. For short-range, line-of-sight communications, the VHF (very high frequency) and UHF (ultra high frequency) spectrum's have proven to be more appropriate for use, whereas for longer range the HF (high frequency) is more appropriate. Ham radio antennas can either transmit or receive electromagnetic waves depending on the type of system they are designed for use.

Features

Ham radio antenna performance is measured by three antenna properties: polarization, feed point impedance and directivity, efficiency and gain. An antenna's polarization is equal to that of its electric field in the vector toward the strongest signal strength. Polarization is measured in two means: horizontal and vertical. Antenna feed point impedance is equivalent to that of the alternating current (AC) resistance and much match that generated by the radio. Gain of an antenna is equal to the power supplied to the antenna less power loss while directivity is the strength of greater radiation of the antenna in one direction over another.

Potential

The future of ham radio lies in the experimentation and adoption of advanced computer software for greater application ideas for ham radio operators. Two areas of current research that pose great potential are increased research into advanced networking and broadcast protocols through the use of the TCP/IP protocol over the ham radio waves as well as spread spectrum transmission and receiving technology. Although there will also be a place for the HF transmission of Morse code for the ham enthusiast, the future of the field lies with greater adoption of technology.

Resources

• Ham Radio History and Prognosis
• Ham Radio Catalog of Antennas and Antenna Kits