ALTERNATE MICROPHONES AND INSTALLATION
For best results, the user should select a low-impedance dynamic type
microphone or a transistorized microphone. Transistorized type microphones
have low output impedance characteristics. The microphones must be
provided with a four-lead cable. The audio conductor and its shielded lead
comprise two of the leads. The third lead is for transmit control and the
fourth is for receiving control.
The microphone should provide the functions shown in schematic below.
4 WIRE MIC CABLE
Pin Number
Mic Cable Lead
1 Audio
Shield
2 Audio
Lead
3 Transmit
Control
4 Receive
Control
Fig. 1
Your transceiver microphone schematic.
If the microphone to be used is provided with precut leads, they must be
revised as follows.
1. Cut leads so that they extend 7/16" beyond the plastic insulating jacket of
the microphone cable.
2. All leads should be cut to the same length. Strip the ends of each wire
1/8" and tin the exposed wire.
Before beginning the actual wiring, read carefully the circuit and wiring
information provided with the microphone you select. Use the minimum heat
required in soldering the connections. Keep the exposed wire lengths to a
minimum to avoid shorting when the microphone plug is reassembled.
Fig. 2
Microphone plug wiring
To wire the microphone cable to the plug provided, proceed as follows :
1. Remove the retaining screw.
2. Unscrew the housing from the pin receptacle body.
3. Loosen the two cable clamp retainer screws.
4. Feed the microphone cable through the housing, knurled ring and washer
as shown Figure 2.
- 15 -
- 16 -
