SAC SA100, Manual

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SOUTHERN AVIONICS COMPANY
Model SA100 Dual 1-7 Introduction
1.3 General Description: SA Radiobeacon Control
System
The Southern Avionics Radiobeacon Control System indicates transmitter system status and
selects and controls the active transmitter. Control of the transmitter system can be exercised
through the Local Radiobeacon Control Panel located at the transmitter site or through one or
more optional Remote Radiobeacon Control Panels located at remote sites. Indication of
transmitter system status without control is available through the optional Remote Radiobeacon
Indicator Panel. Communications between the local and remote panels is through a single
bidirectional two-wire audio grade telephone-type channel. This can be implemented by 600
Ohm wire pair, microwave link, hf link, optical link, or similar circuit. Data transmission rate is
equivalent to approximately 300 baud, with data FSK encoded on U.S. Standard frequencies of
1270Hz, 1070Hz, 2225Hz, and 2025Hz. Transmission is by special protocol to ensure accurate
data transmission over noisy data channels. Data link update is indicated at each control and
indicator panel by LED's which flash with each data update. Transmitter system operation is not
affected by loss of the control channel. Control status in the Local Radiobeacon Control Panel is
maintained by latching control circuits to insure operation during loss of the control data link and
to insure automatic resumption of operation following power failures.