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Performing a VHF Marine Radio Check

Sea Tow Automated Radio Check System no longer available:

For several years, Sea Tow operated an Automated Radio Check System available on VHF-FM CH 24 and CH 28 for the benefit of mariners in over 130 locations. This was discontinued on October 2nd, 2020.

How to test a VHF Radio using Rescue 21 on VHF-FM Channel 70:

For DSC radios equipped with a Test Call feature, the U.S. Coast Guard (USCG) continues to offer an automated DSC Test Call capability from each of its Rescue 21 coastal stations on VHF-FM CH 70 (156.525MHZ). (All fixed mount marine radios certified by the Federal Communications Commission since 1999 are required to have a DSC capability. All such radios sold since 2011 must also have a DSC test call capability.) Marine radios transmitting and successfully receiving a response from a DSC test call can be expected to operate acceptably in the voice mode as well. Test transmissions can be made to another vessel by using a routine individual call to the other radio’s Maritime Mobile Service Identity (MMSI). Please consult your radio manufacturer’s manual to determine proper operation.

To perform a DSC Test Call with the USCG, enter the coast station group identity “003669999” into the radio’s DSC memory. Once stored, a DSC test call can be made by executing the following three steps:

(1) Select “Test Call” from the radio’s DSC menu, (2) Select the USCG number entered into memory, and (3) Transmit the call.

The radio display should indicate when that test call is acknowledged and display the acknowledging station’s nine-digit identity. That identity may be different than the group identity previously entered into memory.

Under no circumstances should a DSC Distress Alert be sent to test your radio.

Voice Radio Checks:

For radio checks by voice with other boaters, please use VHF-FM CH 09 (156.45MHz). The USCG does not monitor CH 09. Please refrain from using VHF-FM CH 16 (156.8MHz).

Please send questions concerning this notice to USCG Spectrum Management and Communications Policy Division (CG-672) at HQS-SMB-CG-672@USCG.MIL or to the Coast Guard Navigation Center’s “Contact Us” page by selecting ”Maritime Telecommunications” as the subject. More information is available at www//


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