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Old 11-11-2011, 14:48   #16
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Re: DSC Position Request from Handheld with Boat's MMSI

One digit (I think maybe the last one) signifies the group. They will differ so you can have more than one MMSI coded devices - one on ship, one in tender, etc.. They will all be coded with your assigned MMSI though.

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Old 11-11-2011, 15:13   #17
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Re: DSC Position Request from Handheld with Boat's MMSI

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Iv'e never heard of this and frankly, don't believe it for a second. Do you have any documented proof of this function?
There probably a lot of things you've never heard of, and many more that you'd not believe. Documentation, how about the USCG? However, you'll need to watch this:
VHF Marine Radio - DSC Radio USCG- Pt. 1
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VHF Marine Radio - DSC Radio USCG- Pt. 2

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VHF Marine Radio - DSC Radio USCG- Pt. 3


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Old 11-11-2011, 16:03   #18
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Re: DSC Position Request from Handheld with Boat's MMSI

I like to keep my GX2150 on whenever I am on the boat however it doesn't like it when I dont have my gps on. It goes into alarm when it doesnt know where it is. My GPS is outside and when at anchor or the dock I take it down below, my vhf is down below and I have a RAM mic by the GPS at the helm.
Not to hijack but does anyone else have this problem? I think it is important to keep it on to be used as a repeater.....
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Old 11-11-2011, 16:25   #19
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Re: DSC Position Request from Handheld with Boat's MMSI

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Originally Posted by fairbank56 View Post
The radio sending the request won't respond as it won't receive the position request because it can't receive while sending.

Eric
err yes it does see class D. all proper DSC radios have a seperate DSC receiver. However youre confusing the issue, a radio sending a position polling does not respond to itself as the software is so arranged

Dave
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Old 11-11-2011, 16:32   #20
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Re: DSC Position Request from Handheld with Boat's MMSI

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Originally Posted by ShaunJ View Post
I like to keep my GX2150 on whenever I am on the boat however it doesn't like it when I dont have my gps on. It goes into alarm when it doesnt know where it is. My GPS is outside and when at anchor or the dock I take it down below, my vhf is down below and I have a RAM mic by the GPS at the helm.
Not to hijack but does anyone else have this problem? I think it is important to keep it on to be used as a repeater.....
All valid issues encountered without the GPS. The DSC REQUIRES the GPS signal. We have ours connected to our chartplotter and a separate GPS that comes on with the radio.
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Old 11-11-2011, 16:39   #21
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Re: DSC Position Request from Handheld with Boat's MMSI

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Originally Posted by Seahunter View Post
There probably a lot of things you've never heard of, and many more that you'd not believe. Documentation, how about the USCG? However, you'll need to watch this:
VHF Marine Radio - DSC Radio USCG- Pt. 1
+
VHF Marine Radio - DSC Radio USCG- Pt. 2

+
VHF Marine Radio - DSC Radio USCG- Pt. 3


This cant be a serious video, the guy hasnt a clue. he confuses GMDSS with SOLAS, he doesnt know the correct term for MMSI.

And then the nonsense. DSC Distress alerts are NOT relayed automatically from boat to boat. In fact ITU specifically forbids it. The operator uses a verbal DSC routine all ships call, Mayday relay to forward on the distress BY VOICE,

Any CLass A DSC radio ( as carried by ships) can acknowledge a DSC and cause the auto broadcast to stop,

Jeez where did they get that clown.

Dave
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Old 11-11-2011, 16:41   #22
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Re: DSC Position Request from Handheld with Boat's MMSI

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All valid issues encountered without the GPS. The DSC REQUIRES the GPS signal. We have ours connected to our chartplotter and a separate GPS that comes on with the radio.
DSC does not require a GPS, under ITU regulations you have a facility to manually enter your position.


I can see how far the US is behind in its understanding of DSC....
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Old 11-11-2011, 16:42   #23
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Re: DSC Position Request from Handheld with Boat's MMSI

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There probably a lot of things you've never heard of, and many more that you'd not believe. Documentation, how about the USCG?
As a professional marine electronics service technician, Iv'e heard a lot. In the video, he was talking about class A DSC. Recreational users like us are using class D units which do not do distress relay transmissions. Class D units do 6 types of DSC transmissions while class A do 16 if memory serves my correctly.

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Old 11-11-2011, 16:45   #24
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Re: DSC Position Request from Handheld with Boat's MMSI

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This cant be a serious video, the guy hasnt a clue. he confuses GMDSS with SOLAS, he doesnt know the correct term for MMSI.
I caught that as well and he also says not to transmit on channel 70 as it should be used for DSC only. By design, with a DSC radio, you can't transmit on channel 70 other than by DSC.

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Old 11-11-2011, 16:50   #25
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Re: DSC Position Request from Handheld with Boat's MMSI

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Originally Posted by goboatingnow View Post
err yes it does see class D. all proper DSC radios have a seperate DSC receiver. However youre confusing the issue, a radio sending a position polling does not respond to itself as the software is so arranged

Dave
Yes, it has a separate receiver, but it cannot receive while the radio is transmitting. The radio sending the position request does not receive it's own transmission.

Eric
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Old 11-11-2011, 16:54   #26
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Re: DSC Position Request from Handheld with Boat's MMSI

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Originally Posted by fairbank56 View Post
As a professional marine electronics service technician, Iv'e heard a lot. In the video, he was talking about class A DSC. Recreational users like us are using class D units which do not do distress relay transmissions. Class D units do 6 types of DSC transmissions while class A do 16 if memory serves my correctly.

Eric

NO DSC radio , class A,B,D or H does auto DSC relay. ITU regs forbid it. Class A has a seperate dsc antenna and seperate DSC TX and RX, It also can acknowledge DSC Distress alerts and cancel them.

Dave
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Old 11-11-2011, 17:02   #27
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Re: DSC Position Request from Handheld with Boat's MMSI

While DSC radios offer "Ship to Ship" communications, the "RED" button sends out and seeks a land based response. A ship who hears a mayday on DSC can communicate with the stricken boat, but this has nothing to do with the automated signal. I'm appalled at the ignorance here on the use of DSC and its operation.
USCG: Rescue 21
Digital Selective Calling
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Old 11-11-2011, 17:10   #28
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Re: DSC Position Request from Handheld with Boat's MMSI

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NO DSC radio , class A,B,D or H does auto DSC relay.
True, they don't do auto relay, but can do manual relays. If no ack is heard within 5 minutes of receiving a distress call, the operator has the option to do a relay and can also do a distress relay acknowledgment.

Eric
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Old 11-11-2011, 17:12   #29
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Re: DSC Position Request from Handheld with Boat's MMSI

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Originally Posted by Seahunter View Post
While DSC radios offer "Ship to Ship" communications, the "RED" button sends out and seeks a land based response. A ship who hears a mayday on DSC can communicate with the stricken boat, but this has nothing to do with the automated signal. I'm appalled at the ignorance here on the use of DSC and its operation.
USCG: Rescue 21
Digital Selective Calling
yes thats right, but what are you specifically giving out about
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Old 11-11-2011, 17:19   #30
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Re: DSC Position Request from Handheld with Boat's MMSI

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I'm appalled at the ignorance here on the use of DSC and its operation.
I'm afraid it's your ignorance and apparently some with the CG. Your statement, "With DSC, the signal repeats itself through other DSC radios in the area until it connects to somebody who actually cares" is incorrect. DSC radio's do not act as repeaters on a received distress or distress relay call, plain and simple. Operators of class A radio's can initiate a relay call but class D radio's can't even do that.

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