6
The relay’s actuation circuit is designed to operate with a typical transceiver’s “KEY” signal. The
power inserter has internal DIP switches that can be programmed to harmonize relay actuation with
the proper state of the transceiver’s KEY signal.
The default setting is such that when the KEY output is “low” (less than 0.7 VDC) the relay turns
on and disconnects the preamplifier’s power and the connection to your receiver is grounded
through a resistor. If the KEY signal is “high” or greater than 1.2 VDC the relay is not actuated and
power is applied to the preamplifier and connection is made to your receiver. If the KEY input to
the power inserter is left open or disconnected, then power is always applied to the preamplifier. If
your transceiver has a “KEY” output that goes high on transmit, then you can reverse the polarity of
the power inserter relay actuation by removing the power inserter’s base plate and programming the
DIP switches on the PC board in accordance with the table shown.
KEY INPUT
Switch 1 Switch 2
20 VDC ANTENNA POWER
Low
Off
On
Off
Factory Default
Setting
High
Off
On
On
Low
On
Off
On
High
On
Off
Off
A simplified schematic of the relay
interface circuit is shown. Note that the
KEY input is pulled up internally via a
10K ohm resistor to the “high” state.
