TM 1-1520-238-10
Change 3
3-18.1
3. TONE button – Press momentarily.
4. A-3-2-T switch – Release.
5. Return to designated frequency or channel.
a. Transmitting TOD from Net Control Helicopter.
NOTE
TOD transmission and reception is normally
performed before flight, but it can be per-
formed in flight.
1. Mode selector switch – MAIN or BOTH, as de-
sired.
2. Function selector switch – MANUAL or PRE-
SET as desired.
3. Frequency selectors – Select predesignated fre-
quency.
or
Preset channel selector – Set to predesignated
channel.
4. Call other helicopter(s) to send time.
5. TONE button – Press momentarily to send TOD.
Listen for 1,020 Hz tone.
b. Receiving TOD.
NOTE
After power-up and WOD transfer, the ra-
dio automatically accepts the first TOD
message received.
To receive TOD in normal mode, after
setting A-3-2-T switch to T, set the radio
to the frequency being used.
1. Mode selector switch – MAIN.
2. Function selector switch – MANUAL or PRE-
SET, as desired.
3. Frequency selectors – Select predesignated fre-
quency for reception of TOD.
or
Preset channel selector – Set to predesignated
channel.
4. Listen for net control helicopter state STANDBY
FOR TIME.
5. A-3-2-T switch – Momentarily to T, then back to
A. Listen for momentary two-tone signal fol-
lowed by a single tone.
c. Entering Net Number.
NOTE
Setting the A-3-2-T switch to A overrides
the hundredths digit in both manual and pre-
set functions, puts the radio in AJ mode and
programs the radio to use the net number in
the three digits following the A.
1. Function selector switch – MANUAL or PRE-
SET, as desired.
2. Frequency selectors – Set second, third and
fourth switches to the desired net number.
or
Preset channel selector – Set to a preset chan-
nel containing the desired net number in its sec-
ond, third and fourth digits.
3. A-3-2-T switch – A.
3.7A RADIO SET RT-1518/ARC-164 HAVEQUICK II
(HQ II) RADIO
The HQ II system consists of a modification to AN/
ARC–164 airborne, (UHF), (AM), radio transmitter-receiv-
er (transceiver) set providing a frequency hopping or anti–
jamming capability. Frequency hopping is a technique
where the designated preset frequency being used for
communication on a given link is automatically frequen-
cy–hopped many times per second. The purpose of this is
to make it difficult for an adversary to jam the link since
they cannot determine which channel is being used. By
the time determination is made as to which frequency is
being used, the communication link has changed to
another frequency.
The frequency–hopping scheme is implemented in the
equipment by storing or initializing every radio with a Word
of Day (WOD), Time of Day (TOD), and a net number. The
WOD programs the frequency–hopping rate and frequen-
cy–hopping pattern. The radio cannot function in the anti–
jamming mode without a valid WOD. Up to six WODs may
be entered at one time. The procedure for storing multiple
WODs is called Multiple
