Antenna: Description and Operation

CIRCUIT OPERATION

Up Operation
When the Radio is turned "ON", the Radio chassis applies battery voltage through circuit 143 to energize the Antenna Relay. With the Antenna Relay energized, the relay contacts close connecting relay terminals C1/A and C2/B. The closed contacts allow voltage from Fuse D7 to be applied to the Antenna Motor through the DK GRN wire.

The Antenna Motor now runs to raise the antenna mast since the motor is now grounded by G401. The motors ground path to G401 passes through the Antenna Motor's up switch, the GRY wire and the energized Antenna Relay. Once the mast is fully extended the up switch in the Antenna Motor opens. The Antenna Motor now stops since it is no longer grounded.

Down Operation
When the radio is turned "OFF", voltage from the Radio chassis is no longer applied to the Antenna Relay's coil causing the relay to de-energize.

With the relay de-energized the relay contacts close to connect relay terminals C1/A and C2/C to each other. These closed relay contacts now allow voltage from Fuse D7 to be applied to the Antenna Motor through the Antenna Motor's down switch. The motor is grounded through the DK ORN wire and the Antenna Relay. The motor now runs in the opposite direction because the polarity of the motor terminals has changed.

The Antenna Mast will now be pulled down until it is fully retracted. At that point, the down switch contacts open, turning "OFF" the Antenna Motor.