How To Decode Maritime Distress Messages GMDSS DSC

[@SDR-DXobserver]

I always like your videos for getting people interested in utility transmissions. Just keep them coming. I'm monitoring these kind of transmissions for the past 40 years, with this may I give you an advice. When making instruction or informative videos it is important to bring the tech stuff exactly as it should as you, in this case, you are acting in a TEACHING capacity. In this video I noticed that you have the SDR setup in a bad way. The tuned frequency of the SDR must be right on spot. 2187.5 kHz is the real reception frequency and the passband filter has to be set exactly to the tones of the transmission, not tuning the frequency around to more or less where you expect the transmission will appear. The international agreement of DSC is a mark and space tone difference of 170Hz with the space tone at 1275 Hz. So the filter is set to start on 1075 Hz at the low side and1645 Hz at the high side. This offers you the exact passband with a 200 Hz extra below and above your target. This offers some flexibility from the skirts of the DSP to not attenuate the signals and at the same time keeping the signals free from unwanted signals that can make YADD tune away from its target when set on autotuning. The advantage is that setting the passband up this way all the DSC frequencies will be spot on in the future and this is important for monitoring a frequency that is only sporadicly transmitting. Also when monitoring all frequencies like scanning or making 9 receivers in SDRconsole all will be received correctly. Just a bit of advice from a dedicated listener. I have also learned this by falling and learning from my mistakes, hi hi. Nu pun intended! Keep up the good work!!!

[@TechMindsOfficial]

Thankyou for this information 🙏

[@chekfakarm2713]

Dear tech mind thank you very much everything on your channel is clear thank you again

[@TechMindsOfficial]

You’re very welcome, thank you for watching 🙏

[@FrugalRadio]

Cool - I've never tried decoding Maritime broadcasts. Could be fun!

[@morphuk1]

Brilliant, thanks for another informative video!

[@TechMindsOfficial]

You're welcome, thanks for watching :-)

[@JoanEA-SWL]

Thank you, very interesting information!

[@TechMindsOfficial]

You're welcome, thanks for watching :-)

[@TallTexasGMan]

Does this software solution work for the VHF Marine Radios as well? Trying to decode MMSI and Lat/Long for inland lakes for recreational maritime use.

[@matteofazio7845]

Steam and SWLing. Great!

[@seanchallenge]

Excellent video thank you from Sean ZS5X. Would like to find out if this can be done on a Raspberry Pi3

[@Solderwire]

Downloaded..set up..running a peach..Thanks

[@TechMindsOfficial]

Which frequency did you manage to get messages on?

[@Solderwire]

@@TechMindsOfficial so far best one is 2.182 it's a 20 meter long wire here.

[@raphaelbrandizi3715]

Do you know how to decod AIVDM frame like !AIVDM,1,1,A

[@maxwang2537]

Nice video. Thanks! That's very cool. What's the program behind YADD?

[@TechMindsOfficial]

Ummm I’ll check

[@richgoffinator]

can you do this with SDRsharp and sytaleC ?

[@drmisfit]

how do you get to hear the radio if vb cable ia selected ,great videos by the way

[@TechMindsOfficial]

You can configure the output to goto your speakers in your sound mixer on windows. Thanks

[@drmisfit]

Thank you very much

[@Zothaqqua]

As a small craft sailor, I'm still hoping that GMDSS does *not* cause ships to stop monitoring VHF channel 16, and I think they should still be required to do so. If you're in a small boat crossing the channel, and you see a ship bearing down on you, you can't find out its MMSI in order to ask its intentions. You might be able to pick up its MMSI from AIS transmissions, if you happen to have an AIS receiver and can use it in time to identify the ship from its position, but a ship can run you down in 15 minutes from the horizon. Long live reliable analogue systems!

[@explorer914]

Well since mariners still uses paper charts I don't think keeping watch on Channel 16 will go away.

[@mustaphacherkaoui970]

Nice video, very interesting,

[@MegaBmwdude]

Nice video, very interesting, cheers

[@TechMindsOfficial]

You’re welcome 🙏

[@altypeRR]

Could I correct a couple of things that are incorrect in the video? Or at least not entirely correct. Firstly the MMSI number, the 9 digits you mention, is the only identification transmitted as part of the message. I’d suggest the system is using some sort of look up database which unless it is regularly updated might not be correct. Secondly DSC is a part of GMDSS and dependant upon the sea area under it they operate in the may have VHF (which will be phase modulated) MF (as you identify using USB) or HF (again using USB). HF operates on 4-6 separate frequencies within the HF band to give global coverage.

[@TechMindsOfficial]

I didn’t go into too much history behind all the technicalities as it would just swamp the topic of the video, so I left the wiki page link for people to go ahead and read :) thanks for watching 🙏

[@Nick_G7IZR]

Shouldn't you have a disclaimer that it is an offence under the WTA to monitor marine transmissions that aren't meant for general reception. A mayday might be ok to monitor, but not general ship to ship or ship to shore. Even my ships licence doesn't allow me to monitor traffic not meant for me! But then I suppose the same applies to most transmissions apart from ham and commercial radio :)

[@TechMindsOfficial]

Well, something that I do not discuss on my channel is Ethics, I simply show you how to do things. It's up to the individual to check local laws etc on what they are doing. It's not my job to tell people to not do something because they want to learn. I will NEVER tell people to do something which is illegal, that's the choice of the individual :-) Thanks for watching though, and people must check local laws, always.. :-)

[@the80hdgaming]

In Canada, we can listen to ANY radio signal with the exception of decrypting encrypted traffic...As long it's not used for personal gain...

[@altypeRR]

GlenAbbey Farms sorry but that isn’t true. The ITU is an international body. They are who make the international radio laws. Interception of maritime radio signals which are not to your station is internationally illegal. You ARE breaking the law by doing so.

[@altypeRR]

Tech Minds but when it’s a criminal act then I think it stops being a matter of ethics. You need to put a disclaimer on how it is illegal internationally to do so.

[@PaulAnslow]

@@altypeRR it is not a criminal act to monitor in some counties.

[@cedric33114]

Hank my friends 73

[@mainsail4959]

2Khz?.....you are talking a bunch of crap!

[@TechMindsOfficial]

Wanna explain yourself with such a bold comment?

[@sk-xv9lt]

This accent is difficult to understand, can't watch it