Chapter 5 FM repeaters
Background
Repeaters are special transceivers that receive on one frequency (the input) and automatically re-transmit the received signal on another output frequency. The retransmitted signal is often sent with higher power, from an antenna with good gain, and from a high-up location that has many line-of-sight paths to surrounding locations.
Equipment
HTs
A handi-talkie or HT is often a new ham’s first radio transceiver.
HTs can be operated by hand, with usually a single press of the thumb on the PTT button to transmit.
Most HTs today are FM-only devices even though the original HTs invented for use in World War II were AM transceivers.
Most HTs operate at 4-5W and are perfect for short-distance communication with repeaters or directly with other hams.
Some HTs operate on a single band, most often 2m. But reasonably affordable dual-band HTs that operate on 2m and 70cm are also popular. A small number of HTs are multi-band, supporting communication on 2m, 1.25m, and 70cm, for example.
HTs usually come with a short, flexible “rubber duck” antenna that works reasonably well outside. But these “ducky” antennas are not especially efficient nor work well inside a vehicle or building. T9A04; T9A07.
Some HTs can even communicate with the APRS network. See the APRS Quest for an APRS-related activity and the section on APRS in the chapter on digital mode operations.
Mobile rigs
A mobile radio offers higher transmit power (50W or more), a bigger screen, and other useful features. These radios can be mounted in a vehicle or used indoors. In both cases, the radios must be connected via coax to a suitable antenna that is matched to the band or bands of operation. Single band (2m or 70cm) and dual band (2m and 70cm) radios are common.