User's Manual

Table Of Contents

Technical Manual Appendices

13 TX DC-FM INPUT OR WIDE BAND INPUT. Select the internal jumper

JMP8 to configure this input as either the DC-FM input or Wide Band input.

Remove jumper if not used.

DC-FM input (JMP8 in position 1-2)

Audio or data may be connected to this point. In order to conform to

transmitter bandwidth emissions limits, this input is hard limited to the peak

deviation and Bessel filtered -3dB @ 3400Hz for minimum group delay

distortion. Input impedance is >10KΩ. Input sensitivity is nominally 1Vp-p but

depends upon RV2 adjustment. If this input is not used then jumper # JMP8 on

the Micro Controller board should be removed to avoid any pickup of stray

signals, or alternatively do not connect any wires to this pin. Avoid the use of

ribbon cables longer than 30-50cm as this may result in excess coupling or

crosstalk.

WIDEBAND input: (JMP8 in position 2-3)

Wide band audio or data may be connected to this point. WARNING: In order

to conform to transmitter bandwidth emissions limits, the signal MUST be pre-

filtered and level controlled, failure to do this WILL result in non-compliance

of the TX emission spectrum. This input mode is not normally used except in

special cases.

CTCSS Input: (JMP27 in positions 1-2)

TX Subtone audio may be injected into this connection point. Input sensitivity

is Fixed at 1Vp-p. AC coupled

14 RX MUTE / SQUELCH MONITOR. The RF mute status may be monitored

by reading this voltage. +5volt logic signal indicates mute status. This output is

not CTCSS dependent. Output impedance approx 100Ω. The polarity is

selectable via the internal jumper JMP17.

RECEIVER AUDIO 600Ω. Receiver audio output from op-amp. Default

nominal line level is set to -10dBm. Unbalanced output with common return to

analog Earth.

Table 7-2 CN1 Connections