Automatic transmission system

An automatic transmission system (or occasionally automated transmission system, to avoid confusion with the automatic transmission of an automobile) is an automated system designed to keep a radio transmitter and antenna system running without direct human oversight or attention for long periods.

In the early days of radio, an operator, technician or electrical engineer was required to attend to a transmitter at any time it was operating or capable of operating. Any condition (such as distorted or off-frequency transmission) which could interfere with other radio services would require immediate manual intervention; facilities also had to be monitored for any fault conditions which could impair the transmitted signal or cause damage to the transmitting equipment.

As technology improved, transmitters became more reliable, and electromechanical means of checking and later correcting problems became commonplace. Regulations eventually caught up with these advances, and radio stations (both broadcast and non-broadcast, such as amateur radio repeaters) were allowed to run unattended provided that there was such an ATS installed.

The system monitors conditions such as voltage, current, and temperature within the transmitter cabinet or enclosure, and often has external sensors as well, particularly on the antenna. Some systems have remote monitoring points which report back to the main unit though telemetry links, particularly for lower radio frequencies like AM radio where propagation changes from day to night.

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