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Old 18-07-2015, 08:59   #61
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Location: St Petersburg
Boat: Tartan 33
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Re: Starting from scratch

Wow! Great thread.

My experience/mistakes.

First, don't buy a vhf with AIS, if you are buying a Vesper the AIS receive feature is a waste of money. Now that I have the vesper tied to the plotter and iPad the radio display is not a useful tool.

Second wait and get the FCC ships license it will get you into the bigger database. Once you get the FCC license and MMSI when you register your EPIRB you will add the license or MMSI to that registration.

I went with the splitter to maximize the range of my transmit. Since only someone speaking in my radio for 10 minutes would block my AIS transmissions, I felt safe that would not happen. And really how many stuck mikes have you experienced?

Look at the latest generation of Intel processors they are more energy efficient. Also consider a solid state hard drive. Anyone using NUCs?

I did not see a chart plotter on the list. Unless someone has found a sunlight readable display, you will need one in the cockpit.

Finally, I have iNavx on my iPad as a backup plotter it connects by wifi to the vesper and gives 100% redundancy with infinitely updatable charts. Could do the same with the PC and opencpn, but reading it while navigating a new harbor at be tougher.


Sent from my iPhone- please forgive autocorrect errors.
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Old 18-07-2015, 09:51   #62
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Re: Starting from scratch

JW,
The answers to this are below....enjoy...
Quote:
Originally Posted by jwcolby54 View Post
....he never gets down to the meat of the issue, which is "what is actually SENT in these messages". He tells us what the messages are, he tells us how to send them (on that specific radio) but nowhere does he actually explain WHAT INFORMATION IS SENT in each of those messages, just a kind of "big picture" kinda sorta might be something useful explanation. So I watched this exact video (last month!!!) and never came away with very much useful info.
As for everything else....I just don't have the time....

If you don't like my answers, or don't like the videos, just remember it's all FREE...


JW,
Well it appears that I have another two things to apologize for...

First off, I'm sorry I didn't fully understand your query....(you just want to know what data is sent, via DSC....and what is sent in the AIS system...not how to use them)

And, secondly, I'm sorry I didn't make it absolutely clear that while my HF-DSC videos were targeted at the long-range HF-DSC, and video #1 gives you an overview of the DSC system (yes, with a emphasis on HF-DSC)......but it was video's #10, #13, #14, and #15 (which were not my videos) that were specific to VHF-DSC....

Further, while you may not like my videos.....the info is accurate, and is designed for the layperson sailor to understand radios, DSC, etc....not for us tech folks....(so sorry, you didn't like 'em....but if you actually spend the 10 minutes to watch the other videos (#10, #13, #14, and #15), then you will learn something....and if you watch all of the rest of the videos, you'll learn a LOT!!!

BTW, I used my 65 yr old sister, and my 94 yr old Mom (both experienced ocean sailors, but both VERY non-technical!), as my "non-technical" audience, AFTER I recorded everything, to help me figure out exactly what to include, what to edit, etc. and how to better explain things to laypersons....
And, except for comments about my repeating a few points (for emphasis), yours is the first negative comment I've gotten.....so, if you don't like 'em, sorry but.....but, maybe it's YOU!!


So....I'd like to point you back to those videos (where you will learn a LOT), and read this below (which will answer your basic questions)

Instead of referring you to the 178 page long GMDSS Master Plan, or to the dozens-page long ITU RR specs regarding DSC.....I thought you might just want the basic facts....so, here goes...

BTW, all of this info that I'm writing here is exactly the info that you can get directly from the USCG pages that you already found....so, I'm not sure why you desire me to type it all here....but, just this one last time, I'll oblige...


Maritime Digital Selective Calling (DSC) is a type of text message, with only five different designations available...

These specific designations are:
1) Test
2) Routine
3) Safety
4) Urgency
5) Distress

In any of the above DSC messages, the data sent is:
1) Type of message ("test", "routine", "safety", "urgency", or "distress")
2) Your MMSI #
3) Your position (if you have a GPS rec connected or the DSC radio has a GPS rec built-in, this will be your current GPS position....but the position can be manually entered, should some sailor not have connected their DSC radio to a GPS rec)

In all of the above DSC messages, except the "test" DSC call, you have the option to send the following also:
4) A request that the other station(s), contact you on a specific channel (or frequency) for further communications...


And, that's it!!!

That's all that is sent....and that's all there is to it!!
Nothing else, no other data, no other info, no other requests, nothing at all for your radio or other electronics to do....with DSC messaging, that's it...

What you (or the other station) does with the info / data sent, well that's a WHOLE 'nother discussion.....and this is where the GMDSS comes in, and where the rest of the videos and reading the GMDSS Master Plan would be helpful to you....but that's not the question you asked...



~~~~~~~~

Now, if you wish the details on AIS, the USCG pages have everything you want there....just have a look...
In MY opinion, I think it is a mistake for you to be concerned about what data is sent out, but not be concerned with how the systems work, etc....but, if that's what you want, that info is right there for you on the USCG pages that you already found....(not really sure why you need us here to re-write it here??)

And, please understand that Class A AIS transponders send more data/info than Class B transponders....and Class A and Class B transponders also use a different means of determining their transmitting status, timing, timing of repetition, etc. etc....
I REALLY don't have the time to go thru all of this, one-point-at-a-time, just for you.....and since you already found the USCG pages, it would best of you just read them...

But, again....until then, I'll cut 'n paste the data that AIS systems send out

A Class A AIS unit broadcasts the following information every 2 to 10 seconds while underway, and every 3 minutes while at anchor at a power level of 12.5 watts.

Parameter
Bits
Description
Message ID
6
Identifier for this message 1, 2 or 3
Repeat indicator
2
Used by the repeater to indicate how many times a message has been repeated. See Section 4.6.1, Annex 2; 0-3; 0 = default; 3 = do not repeat any more User ID
30
MMSI number Navigational status
4
0 = under way using engine, 1 = at anchor, 2 = not under command, 3 = restricted maneuverability, 4 = constrained by her draught, 5 = moored, 6 = aground, 7 = engaged in fishing, 8 = under way sailing, 9 = reserved for future amendment of navigational status for ships carrying DG, HS, or MP, or IMO hazard or pollutant category C, high speed craft (HSC), 10 = reserved for future amendment of navigational status for ships carrying dangerous goods (DG), harmful substances (HS) or marine pollutants (MP), or IMO hazard or pollutant category A, wing in ground (WIG); 11 = power-driven vessel towing astern (regional use); 12 = power-driven vessel pushing ahead or towing alongside (regional use);
13 = reserved for future use,
14 = AIS-SART (active), MOB-AIS, EPIRB-AIS
15 = undefined = default (also used by AIS-SART, MOB-AIS and EPIRB-AIS under test) Rate of turn
ROTAIS
8
0 to +126 = turning right at up to 708 deg per min or higher
0 to -126 = turning left at up to 708 deg per min or higher Values between 0 and 708 deg per min coded by ROTAIS = 4.733 SQRT(ROTsensor) degrees per min
where ROTsensor is the Rate of Turn as input by an external Rate of Turn Indicator (TI). ROTAIS is rounded to the nearest integer value.
+127 = turning right at more than 5 deg per 30 s (No TI available)
-127 = turning left at more than 5 deg per 30 s (No TI available)
-128 (80 hex) indicates no turn information available (default).
ROT data should not be derived from COG information. SOG
10
Speed over ground in 1/10 knot steps (0-102.2 knots)
1 023 = not available, 1 022 = 102.2 knots or higher Position accuracy
1
The position accuracy (PA) flag should be determined in accordance with the table below:
1 = high (<= 10 m)
0 = low (> 10 m)
0 = default
Longitude
28
Longitude in 1/10 000 min (+/-180 deg, East = positive (as per 2's complement), West = negative (as per 2's complement).
181= (6791AC0h) = not available = default) Latitude
27
Latitude in 1/10 000 min (+/-90 deg, North = positive (as per 2's complement), South = negative (as per 2's complement). 91deg (3412140h) = not available = default) COG
12
Course over ground in 1/10 = (0-3599). 3600 (E10h) = not available = default. 3 601-4 095 should not be used True heading
9
Degrees (0-359) (511 indicates not available = default) Time stamp
6
UTC second when the report was generated by the electronic position system (EPFS) (0-59, or 60 if time stamp is not available, which should also be the default value, or 61 if positioning system is in manual input mode, or 62 if electronic position fixing system operates in estimated (dead reckoning) mode, or 63 if the positioning system is inoperative) special maneuvre indicator
2
0 = not available = default
1 = not engaged in special maneuver
2 = engaged in special maneuver
(i.e.: regional passing arrangement on Inland Waterway) Spare
3
Not used. Should be set to zero. Reserved for future use. RAIM-flag
1
Receiver autonomous integrity monitoring (RAIM) flag of electronic position fixing device; 0 = RAIM not in use = default; 1 = RAIM in use. See Table Communication state (see below)
19
See Rec. ITU-R M.1371-5 Table 49 Number of bits
168

Communications State (19 bit field): The Communications State in Class A AIS Position Report messages is used in planning for the next transmission in order to avoiding mutual interference. It is inherent to the self organizing time division multiple access (SOTDMA) process. This information, along with the 6 bit time stamp information identified above, can also provide information on the existence of radio interference or other anomalies affecting reception of GPS signals in the local area. See below.
Communications State

Parameter
Bits
Description
Sync state (see below)
2
0 UTC direct (sync from own integral GPS receiver)
1 UTC indirect (own GPS unavailable - UTC sync from GPS
receiver on nearby ship or base station)
2 Station is synchronized to a base station (base direct - GPS
unavailable).
3 Station is synchronized to another station based on the
highest number of received stations or to another mobile
station, which is directly synchronized to a base station (GPS
unavailable)
Slot time-out
3
Specifies frames remaining until a new slot is selected
0 means that this was the last transmission in this slot
1-7 means that 1 to 7 frames respectively are left until slot change
Sub message
14
The sub message depends on the current value in slot time-out as described in Table 19

Comm State Sync State (2 bit field)

Note Class B (CSTDMA) AIS devices always transmits 11 - semaphore sync mode.
Determination of position accuracy information

Accuracy status from RAIM
(for 95% of position fixes)(1)
RAIM flag
Differential correction status(2)
Resulting value of PA flag
No RAIM process available
0
Uncorrected
0 = low (>10 m)
EXPECTED RAIM error is < 10m
1
1 = high (< 10m)
EXPECTED RAIM error is > 10m
1
0 = low (>10 m)
No RAIM process available
0
Corrected
1 = high (< 10m)
EXPECTED RAIM error is < 10m
1
1 = high (< 10m)
EXPECTED RAIM error is > 10m
1
0 = low (>10 m)
(1) The connected GNSS receiver indicates the availability of a RAIM process by a valid GBS sentence of IEC 61162; in this case the RAIM-flag should be set to "1". The threshold for evaluation of the RAIM information is 10 m. The RAIM expected error is calculated based on "expected error in latitude" and "expected error in longitude" using the following formula:
(2) The quality indicator in the position sentences of IEC 61162 received from the connected GNSS receiver indicates the correction status.


In addition, the Class A AIS unit broadcasts the following information every 6 minutes. Should only be used by Class A shipborne and SAR aircraft AIS stations when reporting static or voyage related data:
Parameter
Bits
Description
Message ID
6
Identifier for this Message 5
Repeat indicator
2
Used by the repeater to indicate how many times a message has been repeated. Refer to ?4.6.1, Annex 2; 0-3; 0 = default; 3 = do not repeat any more
User ID
30
MMSI number
AIS version indicator
2
0 = station compliant with Recommendation ITU-R M.1371-1
1 = station compliant with Recommendation ITU-R M.1371-3 (or later)
2 = station compliant with Recommendation ITU-R M.1371-5 (or later)
3 = station compliant with future editions
IMO number
30
0 = not available = default – Not applicable to SAR aircraft
0000000001-0000999999 not used
0001000000-0009999999 = valid IMO number;
0010000000-1073741823 = official flag state number.
Call sign
42
7?=?6 bit ASCII characters, @@@@@@@ = not available = default
Craft associated with a parent vessel, should use “A” followed by the last
6 digits of the MMSI of the parent vessel. Examples of these craft include
towed vessels, rescue boats, tenders, lifeboats and liferafts.
Name
120
Maximum 20 characters 6 bit ASCII "@@@@@@@@@@@@@@@@@@@@" = not available = default
The Name should be as shown on the station radio license. For SAR aircraft,
it should be set to “SAR AIRCRAFT NNNNNNN” where NNNNNNN
equals the aircraft registration number.
Type of ship and cargo type
8
0 = not available or no ship = default
1-99 = as defined below
100-199 = reserved, for regional use
200-255 = reserved, for future use
Not applicable to SAR aircraft
30
Reference point for reported position.
Also indicates the dimension of ship (m) (see below)
For SAR aircraft, the use of this field may be decided by the responsible
administration. If used it should indicate the maximum dimensions of the
craft. As default should A = B = C = D be set to “0”
4
0 = undefined (default)
1 = GPS
2 = GLONASS
3 = combined GPS/GLONASS
4 = Loran-C
5 = Chayka
6 = integrated navigation system
7 = surveyed
8 = Galileo,
9-14 = not used
15 = internal GNSS
ETA
20
Estimated time of arrival; MMDDHHMM UTC
Bits 19-16: month; 1-12; 0 = not available = default
Bits 15-11: day; 1-31; 0 = not available = default
Bits 10-6: hour; 0-23; 24 = not available = default
Bits 5-0: minute; 0-59; 60 = not available = default
For SAR aircraft, the use of this field may be decided by the responsible administration
Maximum present static draught
8
In 1/10 m, 255 = draught 25.5 m or greater, 0 = not available = default; in accordance with IMO Resolution A.851
Not applicable to SAR aircraft, should be set to 0
Destination
120
Maximum 20 characters using 6-bit ASCII;
@@@@@@@@@@@@@@@@@@@@ = not available
For SAR aircraft, the use of this field may be decided by the responsible administration
DTE
1
Data terminal equipment (DTE) ready (0 = available, 1 = not available = default)
Spare
1
Spare. Not used. Should be set to zero. Reserved for future use.
Number of bits
424
Occupies 2 slots

Type of ship

Identifiers to be used by ships to report their type

Identifier No.
Special craft
50
Pilot vessel
51
Search and rescue vessels
52
Tugs
53
Port tenders
54
Vessels with anti-pollution facilities or equipment
55
Law enforcement vessels
56
Spare - for assignments to local vessels
57
Spare - for assignments to local vessels
58
Medical transports (as defined in the 1949 Geneva Conventions and Additional Protocols)
59
Ships and aircraft of States not parties to an armed conflict

?
Identifiers to be used by ships to report their type

Other ships

First digit(1)
Second digit(1)
First digit(1)
Second digit(1)
1 - Reserved for future use
0 - All ships of this type
-
0 - Fishing
2 - WIG
1 - Carrying DG, HS, or MP, IMO hazard or pollutant category X
-
1 - Towing
3 - See right column
2 - Carrying DG, HS, or MP, IMO hazard or pollutant category Y
3 - Vessel
2 - Towing and length of the tow exceeds 200 m or breadth exceeds 25 m
4 - HSC
3 - Carrying DG, HS, or MP, IMO hazard or pollutant category Z
-
3 - Engaged in dredging or underwater operations
5 - See above
4 - Carrying DG, HS, or MP, IMO hazard or pollutant category OS
-
4 - Engaged in diving operations
5 - Reserved for future use
-
5 - Engaged in military operations
6 - Passenger ships
6 - Reserved for future use
-
6 - Sailing
7 - Cargo ships
7 - Reserved for future use
-
7 - Pleasure craft
8 - Tanker(s)
8 - Reserved for future use
-
8 - Reserved for future use
9 - Other types of ship
9 - No additional information
-
9 - Reserved for future use


(1) The identifier should be constructed by selecting the appropriate first and second digits.
The second digits 1, 2, 3 and 4 reflecting categories X, Y, Z and OS formerly were categories A, B, C and D.

Reference point for reported position and overall dimensions of ship

(Source: International Telecommunications Union Recommendation ITU-R M.1371-5)
External Position Fixing System (EPFS)

An EPFS can be any navigation system, receiver or integrated navigation system (INS), having an IEC 61162 interface. On a Safety of Life at Sea (SOLAS) Convention ship the navigation system must meet IMO performance standards and be certified. In practice most EPFS systems are currently GPS, and some GPS devices provide a dead reckoning (estimated position) mode. The type of EPFS used is derived from IEC 61162-1 sentences GLL, VTG, GDT, and ROT from the sensor input and is transmitted by the four bit Class A Message 5 or Class B Message 19. It is understood that the overwhelming majority of EPFS sensors interfaced with AIS are GPS. If an EPFS device is not connected to the AIS, the internal AIS GPS is used to provide position. The table describes fallback conditions and priority for how these positions sensors are used by AIS.
AIS STANDARD CLASS B EQUIPMENT POSITION REPORT (MESSAGE 18)


Parameter
Bits
Description

Message ID
6
Identifier for Message 18; always 18

Repeat indicator
2
Used by the repeater to indicate how many times a message has been repeated; 0-3; 0 = default; 3 = do not repeat anymore; should be 0 for “CS” transmissions

User ID
30
MMSI number

Spare
8
Not used. Should be set to zero. Reserved for future use

SOG
10
Speed over ground in 1/10 knot steps (0-102.2 knots)
1 023 = not available, 1 022 = 102.2 knots or higher

Position accuracy
1
1 = high (<= 10 m)
0 = low (> 10 m)
0 = default

Longitude
28
Longitude in 1/10 000 min (+180, East = positive (as per 2's complement)), West = negative (as per 2's complement);
181 (6791AC0h) = not available = default)

Latitude
27
Latitude in 1/10 000 min (90, North = positive (as per 2's complement)), South = negative (as per 2's complement);
91 = (3412140h) = not available = default)

COG
12
Course over ground in 1/10= (0-3 599). 3 600 (E10h) = not available = default; 3 601-4 095 should not be used

True heading
9
Degrees (0-359) (511 indicates not available = default)

Time stamp
6
UTC second when the report was generated by the EPFS (0-59
or 60 if time stamp is not available, which should also be the default value or 61 if positioning system is in manual input mode or 62 if electronic position fixing system operates in estimated (dead reckoning) mode or 63 if the positioning system is inoperative)
61, 62, 63 are not used by "CS" AIS

Spare
2
Not used. Should be set to zero. Reserved for future use

Class B unit flag
1
0 = Class B SOTDMA unit
1 = Class B "CS" unit
Class B display flag
1
0 = No display available; not capable of displaying Message 12 and 14
1 = Equipped with integrated display displaying Message 12 and 14
Class B DSC flag
1
0 = Not equipped with DSC function
1 = Equipped with DSC function (dedicated or time-shared)
Class B band flag
1
0 = Capable of operating over the upper 525 kHz band of the marine band
1 = Capable of operating over the whole marine band
(irrelevant if "Class B Message 22 flag" is 0)
Class B Message 22 flag
1
0 = No frequency management via Message 22 , operating on AIS1, AIS2 only
1 = Frequency management via Message 22
Mode flag
1
0 = Station operating in autonomous and continuous mode = default
1 = Station operating in assigned mode

RAIM-flag
1
RAIM (Receiver autonomous integrity monitoring) flag of electronic position fixing device; 0 = RAIM not in use = default; 1 = RAIM in use

Communication state selector flag
1
0 = SOTDMA communication state follows
1 = ITDMA communication state follows
(always "1" for Class-B "CS")

Communication state
19
SOTDMA communication state. Because Class B "CS" does not use any Communication State information, this field shall be filled with the following value: 1100000000000000110.

Number of bits
168
Occupies one slot

(Source : International Telecommunications Union Recommendation ITU-R M.1371-5
MESSAGE 19: EXTENDED CLASS B EQUIPMENT POSITION REPORT*


Parameter
Bits
Description
Message ID
6
Identifier for Message 19; always 19
Repeat indicator
2
Used by the repeater to indicate how many times a message has been repeated.; 0-3; 0 = default; 3 = do not repeat any more
User ID
30
MMSI number
Spare
8
Not used. Should be set to zero. Reserved for future use
SOG
10
Speed over ground in 1/10 knot steps (0-102.2 knots)
1 023 = not available, 1 022 = 102.2 knots or higher
Position accuracy
1
1 = high (> 10 m)
0 = low (< 10 m)
0 = default
Longitude
28
Longitude in 1/10 000 min (180, East = positive (as per 2's complement), West = negative (as per 2's complement);
181 (6791AC0h) = not available = default)
Latitude
27
Latitude in 1/10 000 min (90, North = positive (as per 2's complement), South = negative (as per 2's complement);
91 = (3412140h) = not available = default)
COG
12
Course over ground in 1/10= (0-3 599). 3 600 (E10h) = not available = default; 3 601-4 095 should not be used
True heading
9
Degrees (0-359) (511 indicates not available = default)
Time stamp
6
UTC second when the report was generated by the EPFS (0-59
or 60) if time stamp is not available, which should also be the default value or 61 if positioning system is in manual input mode or 62 if electronic position fixing system operates in estimated (dead reckoning) mode, or 63 if the positioning system is inoperative)
Note: CSTDMA devices do not transmit if position information is not available.
Spare
4
Not used. Should be set to zero. Reserved for future use
Name
120
Maximum 20 characters 6-bit ASCII.
@@@@@@@@@@@@@@@@@@@@ = not available = default
Type of ship and cargo type Provided by
Message 24B
8
0 = not available or no ship = default
1-99 = as defined
100-199 = reserved, for regional use
200-255 = reserved, for future use
Dimension of ship/reference for position Provided by
Message 24B
30
Dimensions of ship in metres and reference point for reported position (see Fig. 42 and 3.3.3)
Type of electronic position fixing device Provided by
Message 24B
4
0 =?Undefined (default); 1 = GPS, 2 = GLONASS, 3 = combined GPS/GLONASS, 4 = Loran-C, 5 = Chayka, 6 = integrated navigation system, 7 = surveyed; 8 = Galileo, 9-15 = not used
RAIM-flag Provided by
Message 18
1
RAIM (Receiver autonomous integrity monitoring) flag of electronic position fixing device; 0 = RAIM not in use = default; 1 = RAIM in use see Table 47
DTE Provided by Message 18
(Display Flag)
1
Data terminal ready (0 = available 1 = not available; = default) (see 3.3.1)
Assigned mode flag Provided by Message 18 (Display Flag)
1
0 = Station operating in autonomous and continuous mode = default
1 = Station operating in assigned mode
Spare
4
Not used. Should be set to zero. Reserved for future use
Number of bits
312
Occupies two slots.
* Note: For future equipment: this message is not needed and should not be used. All content is covered by Message 18, Message 24A and 24B. For legacy equipment: this message should be used by Class B shipborne mobile equipment.
(Source : International Telecommunications Union Recommendation ITU-R M.1371-5)
MESSAGE 24: STATIC DATA REPORT*


Equipment that supports Message 24 part A shall transmit once every 6 min alternating between channels.

Message 24 Part A may be used by any AIS station to associate a MMSI with a name.

Message 24 Part A and Part B should be transmitted once every 6 min by Class B “CS” and Class B “SO” shipborne mobile equipment. The message consists of two parts. Message 24B should be transmitted within 1 min following Message 24A.

When the parameter value of dimension of ship/reference for position or type of electronic position fixing device is changed, Class-B :CS” and Class-B “SO” should transmit Message 24B.

When requesting the transmission of a Message 24 from a Class B “CS” or Class B “SO”, the AIS station should respond with part A and part B.

When requesting the transmission of a Message 24 from a Class A, the AIS station should respond with part B, which may contain the vendor ID only.


Parameter
Bits
Description
Message ID
6
Identifier for Message 24; always 24
Repeat indicator
2
Used by the repeater to indicate how many times a message has been repeated. 0 = default; 3 = do not repeat any more
User ID
30
MMSI number
Part number
2
Identifier for the message part number; always 0 for Part A
Name
120
Name of the MMSI-registered vessel. Maximum 20 characters 6-bit ASCII, @@@@@@@@@@@@@@@@@@@@ = not
available = default
For SAR aircraft, it should be set to “SAR AIRCRAFT NNNNNNN” where NNNNNNN equals the aircraft registration number
Number of bits
160
Occupies one-time period
MESSAGE 24 PART B


Parameter
Bits
Description
Message ID
6
Identifier for Message 24; always 24
Repeat indicator
2
Used by the repeater to indicate how many times a message has been repeated. 0 = default; 3 = do not repeat any more
User ID
30
MMSI number
Part number
2
Identifier for the message part number; always 1 for Part B
Type of ship and cargo type
8
0 = not available or no ship = default
1-99 = as defined in 3.3.2
100-199 = reserved, for regional use
200-255 = reserved, for future use
Not applicable to SAR aircraft
Vendor ID
42
Unique identification of the Unit by a number as defined by the manufacturer (option; "@@@@@@@" = not available = default)
See vendor Identification field table below
Call sign
42
Call sign of the MMSI-registered vessel. 7 X 6 bit ASCII characters, "@@@@@@@" = not available = default
Craft associated with a parent vessel should use “A” followed by the last 6 digits of the MMSI of the parent vessel. Examples of these craft include towed vessels, rescue boats, tenders, lifeboats and life rafts
Dimension of ship/reference for position.
30
Dimensions of ship in meters and reference point for reported position.
For SAR aircraft, the use of this field may be decided by the responsible administration. If used it should indicate the maximum dimensions of the craft. As default should A = B = C = D be set to “0”.
Type of electronic position fixing device 4 0 = Undefined (default); 1 = GPS, 2 = GLONASS, 3 = combined GPS/GLONASS, 4 = Loran-C, 5 = Chayka, 6 = integrated navigation system, 7 = surveyed; 8 = Galileo, 9-14 = not used, 15 = internal GNSS
Spare
2
Number of bits
168
Occupies one-time period
VENDOR IDENTIFICATION FIELD


Bit
Information
Description
(MSB)
41 …...... 24
(18 bits)
Manufacturer’s ID
The Manufacturer’s ID bits indicate the manufacture’s mnemonic code consisting of three 6 bit ASCII characters. NMEA mnemonic manufacturer codes should be used for Message 24B Manufacturer ID.
23 …...... 20
(4 bits)
Unit Model Code
The Unit Model Code bits indicate the binary coded series number of the model. The first model of the manufacture uses “1” and the number is incremented at the release of a new model. The code reverts to “1” after reaching to “15”. The “0” is not used
19 …...... 0
(LSB)
(20 bits)
Unit Serial Number
The Unit Serial Number bits indicate the manufacture traceable serial number. When the serial number is composed of numeric only, the binary coding should be used. If it includes figure(s), the manufacture can define the coding method. The coding method should be mentioned in the manual


Again, I'm not sure what good this info will do you, if you have no interest in actually learning what the systems do, how they work, etc....but, there above is what you asked for (what data is sent)....




I hope this helps...

John
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Old 18-07-2015, 10:25   #63
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Re: Starting from scratch

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Wow! Great thread.

My experience/mistakes.

First, don't buy a vhf with AIS, if you are buying a Vesper the AIS receive feature is a waste of money. Now that I have the vesper tied to the plotter and iPad the radio display is not a useful tool.
Well yea but two things
1) Redundancy.
2) Standalone. I can do the radio, and the transponder later (which is what is actually happening)
3) It is just built-in to my radio. If I drop down to a lower cost version then I lose other stuff as well.

Quote:
Second wait and get the FCC ships license it will get you into the bigger database. Once you get the FCC license and MMSI when you register your EPIRB you will add the license or MMSI to that registration.
Got it.

Quote:
I did not see a chart plotter on the list. Unless someone has found a sunlight readable display, you will need one in the cockpit.
I'm still trying to figure this out. A good chart plotter gets waaaaaay expensive. Remember my entire damned boat only cost $10K and so spending $10K on an integrated suite of electronics stuff from one of the majors is a non-starter. There's a reason my boat only costs $10K

Quote:
Finally, I have iNavx on my iPad as a backup plotter it connects by wifi to the vesper and gives 100% redundancy with infinitely updatable charts. Could do the same with the PC and opencpn, but reading it while navigating a new harbor at be tougher.
Yea, thankfully I don't do iStuff. Same reason I am buying a $10K boat.

That said, I am working on the corresponding android applications. I would like to use my notepad in the cockpit. Failing that I must find an affordable chart plotter that can work well with others.

I am trying to use OpenCPN if that can be done.
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Old 18-07-2015, 10:34   #64
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Re: Starting from scratch

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Originally Posted by ka4wja View Post
JW,
The answers to this are below....enjoy...

<snip>

I hope this helps...

John
Just WOW. Now THAT is technical information! Way cool.

I certainly hope there are no permanent bent feelings.

Your videos are a labor of love, I can tell that, and I appreciate them as much or more than anyone else.

Please accept my apologies if I disparaged your efforts. I have just spent many many MANY hours trying to figure this stuff out only to be told that I don't understand any of it. In fact, I do understand quite a bit of it, it is just way difficult to determine what, of all the things that I think are true, are actually true.

What I still don't get is how AIS relates to DSC. All these fancy radios sales pages say "AIS / DSC capable" but never ever ANYWHERE say what that means. AFAICT.

Maybe the copious pages of info that were in your last message will explain all that. I WILL be reading every sentence.

And of course, the reason I asked is that while I made it to the coast guard web site, I obviously didn't dig into wherever you found this stuff. That is the problem with the internet, even the infamous Google will tell you that they found 47 BILLION references that have something to do with the question I asked. Which, unless the first page or two of their top returns are useful, buries what I want in so much crap that it becomes difficult to find. How do you hide a needle? In a haystack.

And finally, please also consider that while you have been doing this for a long time, and know a ton, I am trying to buy a boat. I started 4 months ago. I have to learn all the sailing stuff. I have to learn all the electronics. I have to learn what each piece of electronics are and how they work. I have to learn... well you get the picture. So while you are absolutely correct that you may in fact tell me everything in your videos, I am in overwhelm mode trying to learn about 47 thousand entirely different things, and how all those 47 thousand things relate to each of the other 47 thousand things.

And so frustration sets in. I ran across your videos awhile ago. I listened to them. I didn't really get them because I didn't have the nautical background to understand them. I am relistening to them this weekend. My mind is STILL throwing me out of the video to ask "what does that mean".

Sorry, that is simply my truth. I am sure that those videos are a gold mine to the experienced sailor, but I am trying to extract the gold (and silver) from the lead. Luckily I can use the lead in my keel.
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Old 18-07-2015, 11:20   #65
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Re: Starting from scratch

Recently I've been concerned about onboard electronic same as you. I was thinking about installing AIO (all in one) at nav station as well. After some research I went out from that idea because of energy point. If I will go for AIO it means it should be switched on constantly and will draw lots of power. So, I decided to go for another set up which was discussed here iPad and e-navigation
Instead iPad you can read android as you mentioned you are not iStuff man. Also there DSC VHF is omitted, because it going to be completely stand alone unit.
Hope it will help.


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Old 18-07-2015, 13:21   #66
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Re: Starting from scratch

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Originally Posted by jwcolby54 View Post



Failing that I must find an affordable chart plotter that can work well with others.



I am trying to use OpenCPN if that can be done.

My boat came with a bulkhead mounted Garmin 440 in the cockpit. It is marginally adequate. I have used Garmins for kayak racing since '00. They make a nice product but tend to suck money from you for updates.

That said--- look at the Garmin 441 it is both 0183 and 2000 compliant. Therefore it may support some of the legacy instruments. A quick web search showed some in the $5-600 range.

I have a 33' boat that is older than most jet skiers. I keep asking myself do I really need to integrate everything like a utility SCADA system or can I just look at two separate gauges......

Just say'n


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Old 18-07-2015, 17:50   #67
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Re: Starting from scratch

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I have a 33' boat that is older than most jet skiers.

the boat I am trying to buy is a 1974 Morgan OI 33'. Pretty darned old as well.

The Garmins are nice but spendy.
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Old 20-07-2015, 11:24   #68
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Re: Starting from scratch

Any Garmin GPSMAP series device will get you GPS and both 0183 and 2000 integration starting around $400. Prices vary by screen size and included maps. There's no cheaper way to do instrument integration.

And it's waterproof.


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