Acom 1200S - Page 17

User's Manual | ACOM 1200S | 1.8-54 MHz Linear Power Amplifier
August 2021
S e c t i o n INSTALLATION | Page
17
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60
a) GND stud
First, connect the wing-nut grounding stud of the amplifier (on the rear panel, marked GND) to the station's
grounding system (see Figure 2-2 Rear panel - Connections, Pos. (a)).
WARNING
Note that the grounding system may have to withstand currents over 15 A with
insignificant voltage drop on it. Therefore, it may be necessary to improve it
considerably, i.e., to become less resistive, with heavier leads and lower-resistive ground
path. The grounding leads should be at least 4 mm² (AWG 11 or SWG 13).
For details and recommendations on the grounding and RF counterpoise system concerning the
electromagnetic compatibility see also Section 3.6.f) Elimination of electromagnetic compatibility (EMC)
problems.
b) KEY-IN socket
This is the amplifier's input for receive/transmit control from the transceiver.
The transceiver controls the amplifier from receive mode into transmit mode (RX/TX) by grounding of the
KEY-IN input.
Run a shielded cable from the "ground on transmit" socket or terminal on your transceiver to the amplifier
rear panel KEY-IN socket (see Figure 2-2 Rear panel - Connections, Pos. (b)). The KEY-IN socket uses a standard
RCA phono plug.
The switching voltage presented from amplifier KEY-IN socket to the transceiver
"ground on transmit" output does not exceed 12 V (positive to the ground). The closed-
circuit current is below 6 mA (see Section 8.1.j) Receive / transmit control).
Your amplifier will not work if KEY-IN input is not connected properly.
Transceiver producers give different names to this output and they are for instance
TX-GND, SEND, T/R-LINE, PTT, etc. Some transceivers require that "ground on transmit"
is implemented via a software command, or by changing the setting of a switch on the
rear panel, or interior of the transceiver. Check your transceiver's manual.
c) KEY-OUT socket
This is the amplifier's transmit-enabling control output to the transceiver.
The KEY-OUT socket on the rear panel provides an extra control signal from the amplifier to the
transceiver. This can be used for improving the receive/transmit (RX/TX) switching safety.