10-9 Operating procedures
10-9.1 Radio operations. VHF/FM commercial marine radio (Figure 10-4) operates in the 156.250-162.550 MHz
frequency range, develops up to 25 watts of radio frequency (RF) power, receives 50 channels for operational and
environmental announcements, and transmits on 46 channels. The workboat commercial marine radio is identical to the
marine radio installed on the barge and described in Chapter 5 of this TM. When workboat is deployed in U.S. coastal
waters and marine radio is not being used for two-way communications, monitor channel 16. The following operational
procedures (Chapter 5) should be observed.
When using the radios for two-way communications, observe secure transmission procedures as specified in unit
Communication Electronics Operation Instructions.
Perform the following to turn on the marine radio:
Verify that antenna lead and power lead are properly attached to radio set.
On marine radio power supply, set power switch to ON.
On marine radio (Figure 5-5), turn VOLUME control clockwise to mid-position on dial.
Perform the following to receive from a remote radio station:
On marine radio, turn CHANNEL selector switch to the desired channel in accordance with Table 5-2 in
Chapter 5 of this TM. In most instances, channel 16 is used to establish initial contact and for DISTRESS
and SAFETY communications. Once contact is made on channel 16, the appropriate working channel is
selected and set.
Selection of channel 15 or channel 17 automatically reduces radio output power to
1 watt, In compliance with US FCC regulations.
Select/set the desired HI/LO power setting.
Turn SQUELCH control clockwise until background noise just disappears. Do not adjust control beyond
this point or the marine radio receiver sensitivity will be reduced.
When message is received, adjust VOLUME control to obtain desired listening level.
Perform the following to transmit to a remote radio station.
Do not transmit on frequencies assigned to other radio sets. Refer to Table 5-2,
Chapter 5, for a general listing of channel assignments and the purpose for which
these channels are to be used.
Turn HI-LO POWER selector switch to desired setting.
HI-LO POWER selector switch should Initially be set In LO position (1 watt RF
output power) for near stations (1-2 miles). Use HI position (25 watt RF output
power) when contact cannot be made using low power (LO position) or for distant
stations (over 2 miles).
Turn CHANNEL selector switch to obtain desired channel, normally channel 16, to establish initial contact.
(Channels 16 and 22 are always monitored by the USCG.)