and initial contact. Allow at least one minute under Working Frequencies, may be used for
for a response before switching channels. traffic. The working channels are also used
Once initial contact is established, the for voice weather broadcasts, navigation
Coast Guard HF working channels, listed warnings, and medical communications.
Transmit Receive Boston, MA Norfolk, VA Miami, FL New Orleans, LA
kHz kHz (NMF) (NMN) (NMA) (NMG)
4125 4125 2300-1100GMT 2300-1100GMT 2300-1100GMT 2300-1100GMT
6215 6215 24 HRS 24 HRS 24 HRS 24 HRS
8291 8291 24 HRS 24 HRS 24 HRS 24 HRS
12290 12290 1100-2300GMT 1100-2300GMT 1100-2300GMT 1100-2300GMT
GMDSS Channels DO wait 3 minutes for an acknowledgment
These simplex frequencies are designated
from a coast station before sending a relay of
under the Global Maritime Distress & Safety
a received distress call. If the call remains un-
System for distress and safety communications
acknowledged, and there is no distress traffic
and (except for 2182 kHz) are not normally
on the associated frequency, relay the call to
the nearest coast station and attempt to con-
adio
guarded.
tact the distressed vessel by radiotelephone.
DSC calls addressed MMSI 003669999 will
2182 kHz 8291 kHz
be received by all DSC-equipped USCG coast
4125 12,290
b
and R
stations within radio range.
6215 16,420
DO NOT relay a distress alert to all ships, ide
unless a known distress situation requires
Digital Selective Calling
such a relay. le-S
Certain DSC radios permit relays of both
USCG Coast Stations will acknowledge MF
distress acknowledgments and of other re-
DSC test calls if requested. Work is underway
S
ing
lays, or they may transpose the MMSI of the
on a massive upgrade to the Coast Guard’s
ship in distress when constructing a relay.
VHF distress system, which will include DSC
DO NOT routinely relay these messages, and
capability. In the meantime, the Coast Guard
be certain the MMSI in your relay matches
cannot reliably receive DSC calls on VHF.
the MMSI of the ship in distress before
transmitting.
DSC Frequencies (kHz):
In addition, if your radio is not connected
omms
2187.5; 4207.5; 6312; 8414.5; 12577; 16804.5
to a navigation receiver, delete old position
C
Station MMSI
information stored in the radio.
Chesapeake VA 003669995
Mariners who transmit a false DSC distress
Boston MA 003669991
alert are required to immediately cancel the
Miami FL 003669997
alert.
Belle Chase LA 003669998
If You Inadvertently Transmit
The advent of DSC-equipped SSB radios
A DSC Distress Alert
immediately led to a staggering number Reset the equipment immediately.
of automatically relayed false alarms that Tune for radiotelephony on the associated
threatened to cripple the U.S. Coast Guard’s distress and safety frequency in each band in
response system. Follow these guidelines for which a false distress alert was transmitted.
DSC alerts: Transmit a broadcast message to “All Sta-
If You Receive A DSC Distress Alert
tions” giving the ship’s name, call sign, time
the alert was transmitted and MMSI; and
DO NOT relay a distress alert known to
cancel the false alert on the distress and safe-
have been acknowledged unless you have
ty frequency in each band in which the false
personally determined that further help to
distress alert was transmitted.
the ship in distress is necessary.
The USCG also urges all operators to be-
come GMDSS certified before using HF DSC
equipment.
821