User's Manual

PTT/RTS Input Logic Level- Sets the polarity of the PTT/RTS input. Normally set for active low i.e.
transmitter is activated when this input is at the logic low state. Due to the internal pull-up resistor,
setting this to active high will cause activation of the transmitter when the PTT/RTS input is left
unconnected. The factory default is active low.
Green LED- Sets the operation of the green LED on the front of the radio. The choices are:
a. Off-The green LED is never on.
b. Power ON-The green LED is on whenever the radio is powered up.’
c. Carrier Detect-The green LED is on whenever a carrier is detected that is above the
programmed carrier detect on threshold.
d. RX Synthesizer Lock-The green LED is on whenever the frequency synthesizer is locked while
in receive mode. This is the factory default setting.
Red LED- Sets the operation of the red LED on the front of the radio. The choices are:
a. Off-The red LED is never on.
b. RX-The red LED is on whenever the radio is actually transmitting. This is the factory default
setting.
TX Timeout Timer- Allows for limits on the maximum time the transmitter may be continuously keyed.
When set, the maximum limit is set in the box. To prevent overheating and possible damage to the unit,
this is normally set on with a time of 60 seconds of less. See section 5.4 for limits on maximum key-down
times. The factory default is 60 seconds.
6.5.3 ALIGNMENT
The alignment page is used for setting the values of the digital gain settings which are used for aligning the
unit and setting the gains of the audio paths. The unit leaves the factory already aligned, but the user may
wish to change the values of some of the input and output gain settings. Different systems or modems may
require different input and output levels.
Audio Input (TX) Gain- This input allows adjustment of the signal level to be applied to the modulation
limiter and filter circuits from either the AUX IN or MIC IN inputs. At the maximum gain setting, the AUX
IN signal input can achieve 60% rated modulation with about 25 mv rms input signal while the MIC IN
signal can achieve the same modulation with 4 mv rms in the low gain position and 0.5 mv in the high gain
position. The setting can vary from 0 for muted input to 32 for maximum gain.
Aux Out (RX) Gain- Sets the audio level of the AUX OUT output and also affects the level of the AUDIO
OUTPUT, even though the AUDIO OUTPUT has its own level control (see Audio PA Gain below).
Carrier Detect On and Carrier Detect Off- Sets the carrier detect on and off values in dBm. For proper
operation, always set the carrier detect on value to a higher level than the carrier detect off value. Typical
values might be -100 dBm for carrier detect on and -114 dBm for carrier detect off. The difference between
the two values represents the squelch hysteresis and is used to prevent squelch chatter when the receive
signal is near the squelch setting values. Typical hysteresis would be between 2 and 4 dB.
TX Frequency Trim and RX Frequency Trim- These values allow the transmitter and receiver to be
trimmed on frequency. A typical adjustment range is about +/-2 kHz. This adjustment is set at the factory
and should not be changed except by trained service technicians with the proper equipment.
Audio PA Gain- Sets the audio level of the AUDIO OUT output. Note that the AUDIO OUT level is also
affected by the Aux Out(RX) Gain setting. Therefore, the Aux Out(RX) Gain should be set before setting
the Audio PA Gain, even if the AUX OUT output is not being used. If the AUX OUT output is not being
used, the Audio PA Gain should be set to .
Deviation and Balance- Set such that the maximum deviation will fall within the regulatory requirements
and that the transmit audio response has the correct characteristics. Deviation and Balance do not need to
be adjusted after a change in programmed frequency. New values are calculated by the radio when a
frequency is entered in the frequency menu. The values are shown in the box at the bottom of the page on a
per-channel basis. Note that even though the values may differ by channel, unless the values in the boxes
have been edited, the deviation and balance of the radio will be the same on all channels, just the values to