3.7.4 Warning Tones.
a. A steady warning tone will be heard in the headset
when the AJ mode is selected and TOD, or a valid WOD,
has not been entered.
b. A pulsating warning tone will be heard in the head-
set when an invalid operating net is selected.
3.7.5 Conference Capability.
Conference communication is not possible
when operating in the secure voice mode.
In the AJ mode, the radio can receive and process two si-
multaneous transmissions on the same net. This confer-
ence capability is available by selecting 00, 50, or 75 with
frequency selector 5 and then operating in the AJ mode.
Conferencing is not possible when the net number ends in
In a conference net, the second transmitting radio will au-
tomatically shift its transmission frequency by 25 kHz
when it monitors a transmission on the primary net fre-
quency. The wide band receiver will read both transmis-
sions without the interference normally associated with
two radios transmitting on the same frequency simulta-
neously. Three simultaneous transmission will result in
3.7.6 Guard Operation.
If the guard frequency is being jammed with
the mode selector switch in the BOTH posi-
tion and the radio in the AJ or normal mode,
set the mode selector switch to MAIN.
The guard receiver is not affected by AJ mode operation.
The guard frequency may be monitored regardless of
mode as long as the mode selector switch is set to BOTH.
The BOTH position turns on the main transceiver and
guard receiver. The guard receiver will remain tuned to
243.000 MHz regardless of manual or preset frequencies
selected. When the function selector switch is set to
GUARD, the AJ mode is removed, the guard receiver is
turned off and the main transceiver is set at 243.00 MHz,
making it possible to transmit and receive on the guard
3.7.7 Secure Communication.
The HQ radio has a se-
cure (cipher) communication capability. In either the nor-
mal or AJ mode, the radio can perform cipher mode op-
eration. The effectiveness of communications in the AJ
cipher mode depends on the frequency hop rate. It is rec-
ommended that the slowest hop rate (channel 20 WOD
set at 00) be used during AJ cipher mode operation.
3.7.8 Normal Mode Operating Procedures.
a. Loading Preset Channels.
1. Mode selector switch MAIN or BOTH.
2. Frequency selectors Select frequency to be
set in memory.
3. Function selector switch PRESET.
For HQ radios, do not select channel 20.
4. Preset channel selector Set to channel to be
5. Open the switching unit cover.
6. PRESET button Press. The frequency is now
loaded into memory.
7. Repeat steps 2, 3, 4 and 6 to complete preset-
8. Close and latch switching unit cover.
b. Transmit/Receive (MAIN) Operating Proce-
1. Mode selector switch MAIN.
2. Function selector switch MANUAL.
3. To manually select a frequency, set the five MHz
selector switches until desired frequency is dis-
played in indicator windows.
4. To select a preset channel, rotate preset chan-
nel selector until desired channel is displayed in
CHAN indicator window.
c. Transmit/Receive/Guard Monitor Operating
1. Mode selector switch BOTH.
If reception on the selected frequency inter-
feres with guard frequency reception, de-
tune the radio set by selecting an open fre-
quency or set function selector switch to