PRC1077-MSOP
A-1
APPENDIX A
RADIO RELAY AND REPEATERS
Introduction
The PRC1077 Radio Set is typically limited by line-of-sight range. In flat
country, the typical range is five miles (eight kilometers), however, if the
transceivers are located on elevated sites with line-of-sight, ranges of 20 or 30
miles are easily achievable. Unfortunately, locating transceivers on elevated
sites is not always possible. A relay system uses two PRC1077 positioned on
elevated sites to relay signals. The two transceivers are connected using the
MK-456/GRC Retransmission Cable Kit.
The PRC1077 can also operate in semi-duplex mode through a repeater, which
offers the advantage of a wider area of coverage with greater flexibility over the
relay system.
Radio Relay Operation
An easy way to demonstrate radio relay operation is to examine a manually
operated system. A transceiver and operator (station A) are located at an
elevated site in line of sight range of the two stations (station B and station C)
that want to communicate. Stations B and C cannot communicate directly
because of obstructions in the line-of-sight path between each other. As an
alternative, station B can get a message to station C, using station A as a relay.
Station B transmits a message to station A, who writes down the message, then
transmits the message to station C. This process can be reversed to get a
response back to station B.
This process can be automated using two transceivers connected together with
the retransmission cable kit so that the audio output of the first transceiver is
directly connected to the microphone input of the second transceiver. The
second transceiver is assigned a different frequency from the first transceiver so
it will not interfere with reception. The retransmission cable is 50 feet long
providing adequate distance between the two transceivers to prevent
overloading.
This relay system is effective in extending the communications range between
two transceivers. It is not a suitable system for operating a network of stations
because different frequencies must be used by stations at each end of the relay.
