Repeater Operation; Transmitter Offsets; Reverse Function; Tone Operation - Kenwood TM-721A Instruction Manual

4-4. REPEATER OPERATION
4-4-1. TRANSMITTER OFFSETS
All amateur radio repeaters utilize a separate receiver and
transmitter section. The receiver frequency may be either
above or below the transmitter frequency.
For most repeaters offsets are as follows:
Band 144 MHz 430/440 MHz
Model TM-721A TM-721A TM-721€
Displ TM-721E European U.K.
isplay version version
+ +600 kHz +5 Miz +1.6 MHz
_ —600 kHz -—5 MHz —1.6 MHz —1.6 MHz
- - ' —7.6 MHz
@ Offset Direction
To select the desired transmitter offset direction press the
SHIFT key. Each time you press the key the transceiver will
advance from one offset to the other, i.e. + to —
(- to —- — with European version) to no offset
(simplex).
The transceiver allows you to store the frequency, and off-
set In memory, or you can select these functions directly
from the keyboard.
20
4-4-2. REVERSE FUNCTION
Some repeaters utilize a ''Reverse pair'', i.e. the transmit/
receive frequencies are exactly the reverse of another
repeater. For example repeater A uses 146.000 for a
transmit frequency (OUTPUT) and 146.600 for receive
(INPUT). Repeater B uses 146.000 for its receive and
146.600 for its transmit frequency. It would be inconve-
nient to have to reprogram the transceiver each time if you
were in range of both repeaters.
The REV key allows you to reverse the transmit and receive
frequencies. To use the REVERSE function press the REV
key. The offset indicator ( + or — / — or —
— } will flash OFF and ON in the display to remind you
that you are working a reverse repeater pair.
To return to normal offsets press the REV key again. This
function is also useful to check the input frequency of the
repeater, so that you can determine if you are within
SIMPLEX communications range.
4-4-3. TONE OPERATION
Some repeaters require the use of a control signal to ac-
tivate the repeater. Several versions are currently in use
worldwise.
In the United States sub-audible tones are sometimes used.
With the TH-721A, 38 different sub-audible tone frequen-
cy selections are possible.
With the use of the optional sub-audible tone en-
coder/decoder (TSU-6) also allows for CTCSS (Tone
Squelch) operations. When this option is activated the
squelch of the SUB band will only open when the proper
sub-audible tone is received.