Standard Horizon HX-300 - Manual (Page 36)

HX300 Page 36
9. VHF MARINE CHANNEL ASSIGNMENTS
Tables on the following columns list the VHF Marine Channel assignments
for USA. and International use. Below are listed some data about the charts.
1. VTS. Where indicated, these channels are part of the U.S. Coast Guard’s
Vessel Traffic System.
2. Alpha channel numbers, that is, channel numbers followed by the letter A
(such as Channel 07 A) are simplex channels on the USA. or Canadian
channel assignments whose counterparts in the International assign-
ments are duplex channels. International channels do not use “alpha”
numbers. If you call the Coast Guard on Channel 16, they will sometimes
ask you to “go to channel 22 Alpha.” This is a channel assigned to USA,
and Canadian Coast Guards for handling distress and other calls. If your
radio is set for International operation you will go to Channel 22 instead
of 22 A, and will not be able to communicate with the Coast Guard. To
use Channel 22 A, your radio must be set for USA or Canada operation,
usually by a U/I/C (USA/International/Canada) control or combination of
controls. Channel 22 (without an “A”) is an International duplex channel
for port operations. Some radios indicate an “A” adjacent to the alpha
channels on the display; on others “alpha” is not indicated but the proper
channel is selected based on the U/I/C setting.
3. Bridge-to-Bridge channels (for example, Channel 13) are for use by
bridge operators on inter-coastal waterways and rivers. It is also used by
marine vessels in the vicinity of these bridges for navigation and for com-
municating with the bridge operators. Note that a limit of 1 Watt is speci-
fied for these channels.
4. The S/D column on the chart indicates either S (simplex) or D (duplex).
Simplex means transmitting and receiving on the same frequency. Only
one party at a time can talk, unlike a telephone. Be sure to say “over”
and release your microphone push-to-talk switch at the end of each
transmission. Duplex operation involves the use of one frequency for
transmitting and a separate frequency for receiving. On channels speci-
fied as duplex on the charts, correct mode of operation is established au-
tomatically by your radio when you select a channel; you cannot change
the mode. And you still must release the push-to-talk switch after each
transmission in order to listen to the radio.
5. Channels normally used by recreational boaters are those that include
the term “non-commercial” in the Channel Use column of the chart.
Some of these are shared with other users and some are used only in
certain geographic regions.