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GMDSS tests question.

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  • GMDSS tests question.

    Got a question regarding the weekly GMDSS tests, one of the required weekly tests is telephone transmission from MF/HF.

    Now i assume this is done by sending a dsc routine request through the routine frequencies and set another frequency to talk to through radio telephone.

    So my question is, what frequencies would you use? Anything outside the ones already taken for distress/safety etc?

    And who would you call?? Unless you have some friend in some other ship you cant just hope someone will see the dsc and change the channel to talk to you, and even if they do im not sure whatever they say is reliable.

    Are there any good stations that could be used to test radiotelephony? Aka talk through the radio telephone, get a confirmation that they hear you in order to complete the "radio telephone transmission" weekly test.

  • #2
    When I'm doing my weekly test calls I will set my VHF or MF/HF set to the "Test" function and then pop in the MMSI of a CG station, for MF/HF I will use Lyngby CG if I'm off the UK coast and then for VHF I tend to use when ever CG station is within a 40ish mile radius of the vessel.


    • #3
      Ah yeah forgot to mention, talking about international voyages all around the world, for example im currently around 100nm south of madagascar and that test is weekly.

      So should try some nearby coastguard if any for this test?

      What frequencies do you use on MF/HF? Assume routine DSC to transmit the dsc request, but then you need 2 frequencies to talk to through RT


      • #4
        On international voyages it all depends on propagation with what frequency you should use. I would test out the BBC world service first on 6195, 9410, 12095 and see what you come up with then choose a frequency relative to that. ALRS Vol 1 should have a list of all the coast radio stations. Have a look and see what you can find close to you current pos'n.


        • #5
          On HF the general rule of thumb is that the further away you are/the nearer to noon local time you are the higher the frequency you need to use. On MF daytime range is usually around 150-250 miles (depending on your transmitter power) and 500-600 miles after dark. If you're close to the coast you'll get a lot of noise on MF which will reduce the range somewhat.
          io parlo morse


          • #6
            There are two types of tests . One with voice and other for DSC. Now remember that even if you get voice test all right, you definitely do need to send DSC test message and receive acknowledgement from a station. Lyngby/Willuna is a good option. I believe recently a UK college has started a MF HF station that only responds to DSC request. I cannot remember the name. I am sure you will find it in ADRS/ALRS . Now remember that DSC station acknowledgement is a weekly requirement and you need to prove it with print out preferably to PSC/Vetting Inspector. On the other hand voice ack does not need proof. Also many times I have tried and I have rarely managed to get voice ack on MF HF Frequencies. Even if you send a DSC Alert most Officers merely silences the alert. If you dont manage to get a DSC Acknowledgement from Coast Station, you are allowed occasionally to show DSC Test ack from nearby mobile station. Of course you would need to make appropriate log entry.


            • #7
              250 nm is what's taught but it's very conservative. I use valencia cg from the west coast of Scotland during the day in bad weather and get a response on mf regularly. That'd over a thousand miles.

              Remember it's not just about them receiving the message they have to be assed to answer too


              • #8
                Perhaps everyone could post the details of stations that respond to DSC test calls with an acknowledgement?

                RCC Australia (Wiluna/Charleville) MMSI 005030001 Reponds all HF DSC frequencies, coverage Oceanic area