The International Telecommunications Union has amended the VHF maritime radio channel numbering scheme which will affect 18 channels used in the U.S. New VHF radios will eventually begin using this scheme. Changes to U.S. channel numbers are shown on our U.S. VHF Channels page.
I don't know exactly when the USCG posted that. Their website notes the most recent update was October 6, 2016. I believe that the recommended changes will take place on January 1, 2017.
The changes appear to affect 18 channels which were formerly assigned as split channels for duplex or semi-duplex operation between ship stations and shore stations, mostly for public correspondence and coast guard use. The reassignment appears to end the use of the lower-frequency of the pair, and creates new simplex channels using those frequencies. Several of these channels were already in use in the USA as simplex on the lower frequency pair, designated by the old channel number with an "A" appended. The changed channels and their new numbering scheme are described below:
CH TX-MHz RX-MHz Notes
1001 156.050 156.050 Lower frequency of duplex CH-1, was 01A
1005 156.250 156.250 Lower frequency of duplex CH-5, was 05A
1007 156.350 156.350 Lower frequency of duplex CH-7, was 07A
1018 156.900 156.900 Lower frequency of duplex CH-18, was 18A
1019 156.950 156.950 Lower frequency of duplex CH-19
1020 157.000 157/000 Lower frequency of duplex CH-20
1021 157.050 156.050 Lower frequency of duplex CH-21, was 21A
1022 157.100 157.100 Lower frequency of duplex CH-22, was 22A
1023 157.150 157.150 Lower frequency of duplex CH-23, was 23A
1063 156.175 157.175 Lower frequency of duplex CH-63, was 63A
1065 156.275 157.275 Lower frequency of duplex CH-65, was 65A
1066 156.387 157.375 Lower frequency of duplex CH-66, was 66A
1078 156.935 156.925 Lower frequency of duplex CH-78
1079 156.975 156.975 Lower frequency of duplex CH-79
1080 157.025 157.025 Lower frequency of duplex CH-80, was 80A
1081 157.075 157.075 Lower frequency of duplex CH-81, was 81A
1082 157.125 157.125 Lower frequency of duplex CH-82, was 82A
1083 157.175 157.175 Lower frequency of duplex CH-83, was 83A
The Coast Guard Navigation Center page continues to list a second 1020 as a split channel, but I suspect that is perhaps a mistake on the web presentation. [Update; that error has been corrected on the USCG website--jimh] It is hard to have one channel number be designated to two different uses of the channel. The Navigation Page for channel assignments also gives the permitted uses of all the channels, including these new ones. See http://www.navcen.uscg.gov/?pageName=mtVhf for more details.
The new channels that will be created by this change are really just the new lower frequency pair of old channels 19, 20, 79, and 80. The new channel numbers have been assigned uses as follows:
CH NEW USE
1001 Port Operations and Commercial, VTS. New Orleans/Lower Mississippi area
1005 Port Operations or VTS. Houston, New Orleans and Seattle areas
1007 Commercial. VHF Digital Small Message Services
1018 Commercial. VHF Digital Small Message Services
1019 Commercial. VHF Digital Small Message Services
1020 Port Operations
1021 U.S. Coast Guard only
1022 Coast Guard Liaison and Maritime Safety Information Broadcasts
1023 U.S. Coast Guard only
1063 Port Operations and Commercial, VTS. New Orleans/Lower Mississippi area
1065 Port Operations
1066 Port Operations
1078 Non-Commercial. VHF Digital Small Message Services
1079 Non-Commercial. VHF Digital Small Message Services
1080 Non-Commercial. VHF Digital Small Message Services
1081 U.S. Government only--Environmental protection operations
1082 U.S. Government only
1083 U.S. Government only
As you can see, most of the new channels have remained in their original use for vessel traffic services (VTS), for use by commercial ships, and for use by Coast Guard or other government users. Only new channels 1078, 1079, and 1080 are available for non-commercial use.
VDSMS or VHF Digital Small Message Services
The VHF Digital Small Message Services (VDSMS) is a new use that permits transmission of short digital messages in accordance with RTCM Standard 12301.1. I am sure most boaters have never heard of this standard, so here is a brief summary of it:
Source: http://nebula.wsimg.com/08ac6f768a2ba3f85f01b41f5e19d1bc?AccessKeyId=2D3610E97C8E55B553AE&disposition=0&alloworigin=1RTCM 12301.1, Standard for VHF-FM Digital Small Message Services,
This 4-page standard specifies the minimum functional and technical requirements for VHF-FM Digital Small Message Services (VDSMS). VDSMS are designed to be embodied within an item of equipment capable of receiving and transmitting VHF communication. This is not an equipment standard. VDSMS are intended to provide for short messaging from ship-to-ship, shore-to-ship and ship-to-shore.
VDSMS are intended to operate on frequencies in the international VHF Marine Band defined in Appendix 18 of the International Radio Regulations (RR Ap 18), unless otherwise restricted by regulation. VDSMS may share channels with other services (e.g. voice services) on a non-interference basis. The VHF Data Link (VDL) access method for VDSMS is intended to ensure that a call in progress is not disrupted. VDSMS transmissions have a limited duration and a limited duty cycle to ensure the availability of the channel for other users. VDSMS transmitter emissions masking is intended to protect the users of the adjacent channels.
The body of this standard includes general requirements for VDSMS. Requirements for specific technology implementations will be contained in future separate Annexes that will include packet data structure, message types, error detection/correction and other technical details associated with each technology.
This sounds like the same sort of text messaging as the SMS service used on cellular telephones. Note that the three new channels available to non-commercial users also permit use of VDSMS transmission. Perhaps soon boaters can send short text messages to other boaters. Won't that make life grand?
An astute reader might now ask, "What will happen to the upper-frequency pair of all those duplex channels?" That is a good question. I believe the ITU recommendation includes creating new simplex channels from those higher-frequency pairs, and the naming convention would prefix "20" to the old channel number. There would thus be a bunch of new higher-frequency simplex channels in the VHF Marine Band. For example, the old duplex CH-1 had the ship station transmitting on 156.050 and the shore station transmitting on 160.650. When CH-1 was dissolved into 1001 for simplex at 156.050, that left 160.650 available for simplex, too. That channel would be designated 2001. (A Space Odyssey channel?) The big frequency jump is a problem with using this for ships. Formerly ship transmit channels were all grouped at the very low end of the band, and the typical ship antenna is tuned for that range. Most ship antennas do not have wide VSWR bandwidth, and if you try to transmit into a ship antenna tuned for the low end now at a frequency of 160.650 the VSWR is likely to be above 2:1. It is typical a recreational grade VHF radio will try to shut down transmitter power output if it sees a high VSWR.
For even more details about the new frequencies and the possibilities of even more channels sometime in the future, enjoy reading these two documents:
Interim solutions for improved efficiency
in the use of the band 156-174 MHz by
stations in the maritime mobile service
Characteristics of VHF radio systems and equipment for
the exchange of data and electronic mail in the maritime
mobile service RR Appendix 18 channels
Finally, in case you were wondering if the FCC was interested in your opinion on any of this, you missed the boat. A notice of requests for comments was published in April 2016. See
WIRELESS TELECOMMUNICATIONS BUREAU SEEKS COMMENT ON RADIO
TECHNICAL COMMISSION FOR MARITIME SERVICES PETITION FOR RULEMAKING
TO UPDATE PART 80 OF THE COMMISSION’S RULES
The request for comments concerns changes proposed to PART 80 of the commission's rules (Maritime Radio Services) by the Radio Technical Commission for Maritime Services (RTCM) that were included in their petition to the FCC, "Petition for rulemaking to rewrite Part 80 of the Commission’s rules for Stations in the Maritime Services," filed in February 2016. You can obtain a copy of their petition from
Summary of petition
Full petition with complete details of all proposed changes
RTCM explained their reason for their petition to change the Part 80 rules:
Since the last FCC revision of Part 80 of the rules, these standards and relevant maritime radio technologies have undergone additional changes, revisions and advances. This Petition for Rulemaking is intended to revise Part 80 in response to these changes.
By this Petition, changes have been proposed throughout Part 80 to simplify regulations and to eliminate equipment and procedures which are no longer used.
Searching for any news about RM-11765, I found that many interested parties had filed comments, including:
--Steve Spitzer (of the NMEA)
You can read their comments (and more comments from others) by downloading them from the FCC website at