User's Manual

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
achieve equal balance and deviation may differ. One can actually modify the calculated deviation and
balance values per channel by entering values in the boxes, but this requires the services of a very qualified
technician and the proper test equipment. The radio has been properly aligned at the factory and should not
need to be adjusted. Details on how to perform these adjustments are found in the Alignment section.
TX Low Power and TX High Power-Sets the global power level for the transmitter in watts for the two
positions of the CSN input. A logic high on the CSN input would cause the radio to use the TX High Power
setting while a logic low on the CSN would cause the radio to use the TX Low Power setting. Note that the
names Low and High Power are purely arbitrary and that the Low Power value can actually be set to be
higher than the High Power value if desired. If it is desired that the power levels be set different values for
different channels, the desired power levels can be inserted into the box at the bottom of the page. Note,
however, if a change is made in the TX Low Power and/or TX High Power values in the slide bar area, it
will affect all channels equally.
Instructions for using the alignment page can be found in section 13 of this manual.
6.5.4 SUMMARY
The summary page summarizes the information shown on the other three pages and, in addition, includes
the model and serial number of the unit.
6.5.5 RESTORE EEPROM