Hello to all,
Once again I'd like to add some clarifying information.
Due to my efforts to promote HF-DSC, I unfortunately went too far and inadvertently caused some confusion....please ignore and forget my comments specifically dealing with "routine" HF-DSC signaling (you can skip that video, as well), unless you have some unique/specific need to investigate / learn about "routine" signaling....
Please just stick with the "Distress" (MayDay) signaling and "Safety" (Securite`) signaling (for weather,
navigation, communications testing).
Those of us on private yachts, with the Icom M-802, etc., will mostly be using MF/HF-DSC for "Distress" signaling (MayDay) or "Safety" signaling (for weather,
navigation / communications testing, etc.)....and that's probably it...
And, you're going to be using one of the six Int'l GMDSS DSC "Safety" / "Calling" frequencies
[2187.5khz; 4207.5khz; 6312.0khz; 8414.5khz; 12577.0khz; 16804.5khz]
Although, I already mentioned that the USCG offers "automated DSC Testing" on 4207.5khz, from 3 of their locations, if you are beyond 4mhz comms range, they do accept DSC "Safety" calls for testing / verifying proper HF-DSC system operation, as long as you don't do this often (typically once per year / once per season, or only prior to an ocean passage).
Some additional supporting info for this:
From US FCC Part 80 Rules & Regs (Maritime Mobile Service):
80.359 Frequencies for digital selective calling (DSC).
(b) Distress and safety calling. The frequencies 2187.5 kHz, 4207.5 kHz, 6312.0 kHz, 8414.5 kHz, 12577.0 kHz, 16804.5 kHz and 156.525 MHz may be used for DSC by coast and ship stations on a simplex basis for distress and safety purposes, and may also be used for routine ship-to-ship communications provided that priority is accorded to distress and safety communications. The provisions and procedures for distress and safety calling are contained in ITU-R M.541-9 (incorporated by reference, see § 80.7), and § 80.103(c).
And, some further info (primarily dealing with the
equipment and crew familiarity):
Quote from US Gov't Pub 117:
Use of GMDSS Equipment for Routine Telecommunications; GMDSS telecommunications equipment should not be reserved for emergency use only.
The IMO has issued COMSAR/Circ.17 (dated 9 March 1998) which recommends and encourages mariners to use that equipment for routine as well as safety telecommunications. The following recommendation is extracted from Circ.17:
Use of GMDSS equipment for transmission of general radiocommunications is one of the functional requirements specified in SOLAS chapter IV, regulation 4.
Regular use of GMDSS equipment helps to develop operator competency and ensure equipment availability. If ships use other radio communication systems for the bulk of their business communications, they should adopt a regular program of sending selected traffic or test messages via GMDSS equipment to ensure operator competency and equipment availability and to help reduce the incidence of false alerts.
This policy extends to all GMDSS equipment suites including Digital Selective Calling (DSC) on VHF, MF and HF, to the Inmarsat systems, and to any duplicated VHF and long-range communications facilities.
{Over the years, I've attempted to be a bit less USA-centric, trying to point to the international uses of the GMDSS.....and I've mentioned some sailors recommendations for using MF/HF-DSC in ocean rallies, etc., as well as encouraging the use of "regional MMSI's" for regional-group calling... but these are rather specialized / niche uses, and I now realize that those interested in them will either already be aware or will be smart enough to ask/learn....so, no need for me to be rambling on about them... }
Without going into the weeds of the original GMDSS plan, nor specifically Digital Selective Calling (DSC), please remember that this system was originally designed/planned in the late 1980's / early 1990's, and implemented starting in 1992....so, much has changed....not the least of which most "public correspondence" (ship-to-shore
phone calls) is handled via sat comm, as are most "data comms" that aren't being handled privately via
PACTOR....
While the MF/HF-DSC system (as well as the VHF-DSC system) is an integral part of the GMDSS (Global Maritime Distress and Safety System), the main use these days is the "Distress" signaling and "Safety" signaling, not the "Routine" signaling that was intended to be used for both ship-to-shore and shore-to-ship signaling, by both "public coast stations" (for "public correspondence" and ship's/fleet's business) and "private coast stations" (usually for ship's/fleet's business, using SITOR/FSK)...
So, while we can continue to rely on the GMDSS to be there when we need it [406mhz EPIRB's; NAVTEX; VHF-DSC-FM; MF/HF-DSC-SSB; SafetyNET broadcasts; INMARSAT-C (and now / soon-to-be INMARSAT FB and
Iridium Certus); SART's (AIS-SART's or SART-X's)], we should remember
(or rather I should accept?) that most sailors/cruisers (except those using NAVTEX...mostly in
Europe or Asia), these days only use the GMDSS in times of "Distress"....so...
So, perhaps we could learn something from the IMO (International Maritime Organization) that started the whole SOLAS (Safety-Of-Life-At-Sea) idea, and came up with the GMDSS in the first place?
Maybe we should heed their
advice?
Have a look again at what their
advice / recommendations are:
Use of GMDSS equipment for transmission of general radiocommunications is one of the functional requirements specified in SOLAS chapter IV, regulation 4.
Regular use of GMDSS equipment helps to develop operator competency and ensure equipment availability. If ships use other radio communication systems for the bulk of their business communications, they should adopt a regular program of sending selected traffic or test messages via GMDSS equipment to ensure operator competency and equipment availability and to help reduce the incidence of false alerts.
This policy extends to all GMDSS equipment suites including Digital Selective Calling (DSC) on VHF, MF and HF, to the Inmarsat systems, and to any duplicated VHF and long-range communications facilities.
Perhaps this is simply what I should have recommended from the beginning, some ~ 17 years ago, when I first started touting "HF-DSC"? But, whatever the case, that's what I recommending today!
I do hope this info is helpful to you all.
Fair winds.
John
P.S. Don't forget the "stickies" here, on Maritime HF Comms
Marine SSB Stuff (how-to better use / properly-install SSB, & troubleshoot RFI, etc.)
https://www.cruisersforum.com/forums/f13/marine-ssb-stuff-how-to-better-use-properly-install-ssb-and-troubleshoot-rfi-etc-133496.html
HF-SSB Radio, Proper Installation Tips/Techniques, etc.
https://www.cruisersforum.com/forums...tc-198305.html
And, for those looking for the easy-peasy link to a free video series / Playlists, have a look here:
HF-DSC Comms
https://www.youtube.com/playlist?list=PLnN6ygtZ3h2n3z5nlv-ga2zYuPozhUXZX
VHF-DSC Comms
https://www.youtube.com/playlist?list=PLnN6ygtZ3h2m-IejYg7J6QugtO2epizxF
Generic Maritime HF comms
https://www.youtube.com/playlist?list=PLnN6ygtZ3h2nPNdApNsZDo_Jk3NB_Bt1y
Offshore Weather
https://www.youtube.com/playlist?list=PLnN6ygtZ3h2mPZAx2vWzdjTJjHlChruyY
Icom M-802 Instruction Videos
https://www.youtube.com/playlist?list=PLnN6ygtZ3h2npivDjoFrC-8QKVyMb4tVr
Offshore Sailing
https://www.youtube.com/playlist?list=PLnN6ygtZ3h2nbwAGh5DKgTCj15iyl6qoY