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Notch Tuning and Notch Outphase Control
Notch tuning and notch outphasing has been
factory-adjusted and sealed for the best
2175-Hz notch. Adjustment is not required.
Auxiliary Audio Input and PTT
Auxiliary audio signals connected to TB1-1,2
should be externally level-adjusted after all
line-drive controls have been set. When a
line-drive control has been set for a 0-dBm
function tone, –2 dBm into the auxiliary input
will drive the line at about 0 dBm. An external
switch connected to the AUX PTT input
TB1-3,2 causes tone burst, PTT tone, and
auxiliary audio line drive, but microphone
audio is disabled.
Footswitch PTT
An external switch connected to TB1-12,2 has
exactly the same effect as pressing a PTT
switch.
Tone-Burst Frequency Programming
Console tone frequencies are factory-programmed
by diodes to 2175 Hz (PTT/guard) and to 2050 Hz
(monitor), and DIP-switched programmed to 1950
Hz (F1), 1850 Hz (F2), 1750 Hz (F3), and 1650 Hz
(F4). Refer to Chart 3 to program F1, F2, F3, and
F4 to other frequencies.
Paired F1-F2 and F3-F4 Operational Mode
To change frequency-select mode of operation
from 1-of-N to paired mode, change PAIR
MODE jumper plug P2 to B. In this mode, one
of the F1-F2 pair remains latched on and one of
the F3-F4 remains latched on. F1 and F2 tone
bursts occur from PTT, F1, or F2 switch
operation, while "F3" or "F4" tone bursts occur
only from "F3" or "F4" switch operation. A
typical use of this paired mode is F1 and F2 for
frequency control and F3 and F4 for scan up
and scan down of the remote radio.
Defeat F2, F3, and/or F4
Any of the frequency-select switches may be
defeated by reprogramming the unwanted-frequency
switch to the same frequency as one of the other
frequency switches.
Special Uses for F2, F3, F4
One of the many possible uses for F2, F3, and
F4 with single-frequency radios is selective
control of up to four base-station radios on a
single leased line. The four radios could all be
at the same site or 50 miles apart. In a
three-station system on the same line, one
frequency can be used for simulcast.
Headphones
A stereo headphone jack has been provided so
that selected audio is heard in one ear and
unselected audio in the other. Use of this jack
automatically disconnects the console speakers.
Headphone audio level adjustment is obtained
from the front-panel volume controls. NOTE:
Monaural headphones are not recommended,
because only selected audio is heard; a
monaural plug shorts the output of the
unselected-audio amplifier to ground (through
a resistor).
External Speakers
Normally, if used, a pair of 8-ohm external
speakers is connected to TB1-6,7 and
TB1-9,10. This connection drives the external
speakers with power equal to the internal
speakers. The connection of a single 8-ohm
external speaker to TB1-6,9 drives the external
speaker at a –6-dB level from the selected audio
channel and a –6-dB level from the selected
audio channel. It should be noted that local
audio from or intercom will not be heard from
the external speakers.
Battery Backup or DC Supply Operation.
A 12-volt (13.8-V nominal) vehicular-style
battery connected to TB1-5,4 will provide
backup in case of power failure.
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