Digital Marine Radio Service

Marine radios, which are typically installed on boats, operate on the Very High Frequency (VHF) Marine band. These radios play an indispensable role in maritime safety, greatly contributing to emergency rescue operations and general navigation on the water. They allow for essential communication between vessels and with shore stations, providing up-to-date weather reports, distress signal broadcasts, and a means for vessels to keep in touch with one another. However, while these radios are a critical component of boating safety, they are not without their associated shortcomings. Their performance is greatly influenced by a range of factors; the most critical of these is line of sight. Essentially, for a radio signal to be received, the transmitting and receiving antennas must be within sight of each other. This is often a limiting factor for these radios. Despite the vast expanses of open waters devoid of typical obstructions such as buildings or mountain ranges, another natural obstacle comes into play. This obstacle is the curvature of the earth itself. The earth’s curvature and the closer-than-perceived horizon significantly limit the range of the marine radio. Radio waves will go about 10% beyond the visual horizon. For most power boats, the marine radio has an effective operational range of about 14 miles from boat to boat. This is insufficient to even reach from Los Angeles to Catalina Island. This is because the radio waves travel in a straight path, and beyond certain distances, they simply move past the receiver due to the Earth’s curved surface. Hence, the 14-mile range is essentially a function of the height of the boat’s antenna above the waterline. However, sailboats often have the advantage in this scenario. They usually mount their antennas at the top of their high masts, elevating them above the typical antenna height on power boats. As a result, sailboats can extend the range of their radios to approximately 28 miles from sailboat to sailboat, effectively doubling the communication range of their power boat counterparts. To overcome the limitations of marine VHF radios, services like the Coast Guard, Marine Exchange, and Vessel Assist often utilize strategic locations for their base stations. These organizations typically set up their radio equipment at higher altitudes on land. By doing so, they achieve a significantly greater line of sight, enabling them to extend their communication range considerably further than the typical marine radio. This expanded reach is invaluable in ensuring the safety and efficiency of maritime operations.

Over the years, we have been developing radio systems to overcome the line-of-sight limitations intrinsic to terrestrial mobile and portable radios, commonly imposed by obstructions such as mountains, buildings, and the earth’s curvature. To circumvent these hindrances, we have forged a web of interconnected mountaintop sites. During the creation of this terrestrial network, we extended significant coverage into the Pacific Ocean. A multitude of these mountaintop sites now provide coverage roughly 70 miles seaward and stretch approximately 300 miles from north of Morro Bay to the south of the Mexican border. (We do not recommend using our network south of the Mexican border as we are not licensed to operate in Mexican waters.)

In addition to these advantages, our networked radios provide:
1. The capability to communicate on land, unlike marine radios which are restricted to specific marine entities.
2. Extended communication range into the ocean, beyond the scope of cell phone coverage.
3. Access to private channels, offering a clear line without the need to filter through unrelated stations or handle interference.
4. Conversation encryption to ensure privacy and prevent unauthorized monitoring.
5. GPS tracking for both marine and land based stations.
6. A tailored emergency alert function.
7. The capacity to manage commercial or personal communications without monopolizing a marine frequency.

MRA Channel List

1	Calling Channel	General calls to other vessels
2	Vessel Assist
3	Coast Guard	Non-emergency calls
4	Yacht club 1	Communication directly with clubs
5	Yacht club 2
6	Yacht club 3
7	Yacht club 4
8	Yacht club 5
9	Yacht club 6
10	Yacht club 7
11	Yacht club 8
12	Yacht club 9
13	Yacht club 10
14	Commercial 1	General purpose commercial traffic
15	Commercial 2
16	Commercial 3
17	Commercial 4
18	Commercial 5
19	Commercial 6
20	Commercial 7
21	Commercial 8
22	Commercial 9
23	Commercial 10
24	Talk group 1	General conversations
25	Talk group 2
26	Talk group 3
27	Talk group 4
28	Talk group 5
29	Talk group 6
30	Talk group 7
31	Talk group 8
32	Talk group 9
33	Talk group 10
34	Marina 1	Communications with Marinas
35	Marina 2
36	Marina 3
37	Marina 4
38	Marina 5
39	Marina 6
40	Marina 7
41	Marina 8
42	Marina 9
43	Marina 10
44	Private 1	Private channels can be configured for exclusive use of a group. Encryption is also available.
45	Private 2
46	Private 3
47	Event 1	Channel for a particular event.
48	Event 2
49	Event 3
50	Event 4

Signal Level Map

Mobile and Portable Coverage Map

Google Earth Maps

The maps below can be viewed in Google Earth. These maps contain greater detail than those above.

Signal Level Map

Mobile Coverage

Handheld Coverage

Portable/Mobile

VHF Marine Frequencies
New Channel Number	Old Channel Number	Ship Transmit MHz	Ship Receive MHz	Use
1001	01A	156.050	156.050	Port Operations and Commercial, VTS. Available only in New Orleans / Lower Mississippi area.
1005	05A	156.250	156.250	Port Operations or VTS in the Houston, New Orleans and Seattle areas.
06	06	156.300	156.300	Intership Safety
1007	07A	156.350	156.350	Commercial. VDSMS
08	08	156.400	156.400	Commercial (Intership only). VDSMS
09	09	156.450	156.450	Boater Calling. Commercial and Non-Commercial. VDSMS
10	10	156.500	156.500	Commercial. VDSMS
11	11	156.550	156.550	Commercial. VTS in selected areas. VDSMS
12	12	156.600	156.600	Port Operations. VTS in selected areas.
13	13	156.650	156.650	Intership Navigation Safety (Bridge-to-bridge). Ships >20m length maintain a listening watch on this channel in US waters.
14	14	156.700	156.700	Port Operations. VTS in selected areas.
15	15	—	156.750	Environmental (Receive only). Used by Class C EPIRBs.
16	16	156.800	156.800	International Distress, Safety and Calling. Ships required to carry radio, USCG, and most coast stations maintain a listening watch on this channel.
17	17	156.850	156.850	State & local govt maritime control
1018	18A	156.900	156.900	Commercial. VDSMS
1019	19A	156.950	156.950	Commercial. VDSMS
20	20	157.000	161.600	Port Operations (duplex)
1020	20A	157.000	157.000	Port Operations
1021	21A	157.050	157.050	U.S. Coast Guard only
1022	22A	157.100	157.100	Coast Guard Liaison and Maritime Safety Information Broadcasts. Broadcasts announced on channel 16.
1023	23A	157.150	157.150	U.S. Coast Guard only
24	24	157.200	161.800	Public Correspondence (Marine Operator). VDSMS
25	25	157.250	161.850	Public Correspondence (Marine Operator). VDSMS
26	26	157.300	161.900	Public Correspondence (Marine Operator). VDSMS
27	27	157.350	161.950	Public Correspondence (Marine Operator). VDSMS
28	28	157.400	162.000	Public Correspondence (Marine Operator). VDSMS
1063	63A	156.175	156.175	Port Operations and Commercial, VTS. Available only in New Orleans / Lower Mississippi area.
1065	65A	156.275	156.275	Port Operations
1066	66A	156.325	156.325	Port Operations
67	67	156.375	156.375	Commercial. Used for Bridge-to-bridge communications in lower Mississippi River. Intership only.
68	68	156.425	156.425	Non-Commercial. VDSMS
69	69	156.475	156.475	Non-Commercial. VDSMS
70	70	156.525	156.525	Digital Selective Calling (voice communications not allowed)
71	71	156.575	156.575	Non-Commercial. VDSMS
72	72	156.625	156.625	Non-Commercial (Intership only). VDSMS
73	73	156.675	156.675	Port Operations
74	74	156.725	156.725	Port Operations
77	77	156.875	156.875	Port Operations (Intership only)
1078	78A	156.925	156.925	Non-Commercial. VDSMS
1079	79A	156.975	156.975	Commercial. Non-Commercial in Great Lakes only. VDSMS
1080	80A	157.025	157.025	Commercial. Non-Commercial in Great Lakes only. VDSMS
1081	81A	157.075	157.075	U.S. Government only – Environmental protection operations.
1082	82A	157.125	157.125	U.S. Government only
1083	83A	157.175	157.175	U.S. Coast Guard only
84	84	157.225	161.825	Public Correspondence (Marine Operator). VDSMS
85	85	157.275	161.875	Public Correspondence (Marine Operator). VDSMS
86	86	157.325	161.925	Public Correspondence (Marine Operator). VDSMS
87	87	157.375	157.375	Public Correspondence (Marine Operator). VDSMS
88	88	157.425	157.425	Commercial, Intership only. VDSMS
AIS 1	AIS 1	161.975	161.975	Automatic Identification System (AIS)
AIS 2	AIS 2	162.025	162.025	Automatic Identification System (AIS)