RSSI

(when

fitted)

Figure 3

RV1

PL2

IC4

Location of

RSSI pin

when fitted

C15

L8

Figure 4

CONNECTION

The type of radio antenna connector (via RF) is determined by the letter designator as

follows:

S -

SMB miniature coaxial

connector

A -

flying lead with a BNC

connector

P -

PTFE (bush) feedthrough

The audio output (AF), squelch output (SQ) and DC supply (+V) connections are made

via feedthrough pins. These pins incorporate RF filtering, thus ensuring compliance

with the spurious radiation levels required by MPT1329 and similar specifications. The

squelch output (SQ) is an NPN open collector transistor driver. Connecting the anode

of a LED to the input supply rail and the cathode to the squelch output, via a suitable

current-limiting resistor, will provide an LED that is illuminated when no RF signal is

present.

RSSI Option

An ‘S’ meter output is always available for set-up purposes on the internal test point

TP1.

Depending on the version specified this signal may be wired to an extra

feedthrough pin, or it may replace the SQ output (the squelch mute will still operate in

this instance)