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nmea - talkers - listeners and lessons learned.
When I got my second nmea device, i was excited -- "hook it up" the manual said
-- support said "yes; you just hook up all the nmea out with nmea in of the other devices and visa versa" so I did. It appeared to work. however, since I have some weird things recently discovered, we've traced it down to the fact that the info I got was wrong; and my understanding of nmea was woefully weak. GPS: listens & talks (2 lines of each) RADAR: listens & talks navtex: listens only autopilot: listens only flowscan: listens only VHF listen/talk Navtex, Autopilot & flowscan need to listen to the gps radar & gps need to listen & talk to each other The VHF radio talks/listens to the gps. AIS receiver is in the budget & will need to talk to the gps & radar. From a few hours search; it seems I need multiple-multiplexers to make this work "correctly" -- can anyone give me a hand? -josh |
nmea - talkers - listeners and lessons learned.
Josh Assing wrote:
When I got my second nmea device, i was excited -- "hook it up" the manual said -- support said "yes; you just hook up all the nmea out with nmea in of the other devices and visa versa" so I did. It appeared to work. however, since I have some weird things recently discovered, we've traced it down to the fact that the info I got was wrong; and my understanding of nmea was woefully weak. GPS: listens & talks (2 lines of each) RADAR: listens & talks navtex: listens only autopilot: listens only flowscan: listens only VHF listen/talk Navtex, Autopilot & flowscan need to listen to the gps radar & gps need to listen & talk to each other The VHF radio talks/listens to the gps. AIS receiver is in the budget & will need to talk to the gps & radar. From a few hours search; it seems I need multiple-multiplexers to make this work "correctly" -- can anyone give me a hand? -josh I have had exactly the same problem with (almost) exactly the same stuff you have. Multiplexers did not fit the bill for me since their inputs are usually limited to 4800bps while many NMEA sentences (like HDT) should be transmitted much more frequently. In the end I managed by intelligently coupling the nmea i/o ports on all my devices (most of my devices have multiple NMEA in and out) and for the few connections I couldn't 'fit' I wrote a WIN32 based program for the navigation computer that combined the input from a few serial-USB converters into one serial 38k4 stream. In any case, if you decide to go for NMEA multiplexers make sure they support the speed you require. |
nmea - talkers - listeners and lessons learned.
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nmea - talkers - listeners and lessons learned.
On Tue, 15 Jul 2008 10:29:00 -0700, Josh Assing
wrote: When I got my second nmea device, i was excited -- "hook it up" the manual said -- support said "yes; you just hook up all the nmea out with nmea in of the other devices and visa versa" so I did. It appeared to work. however, since I have some weird things recently discovered, we've traced it down to the fact that the info I got was wrong; and my understanding of nmea was woefully weak. GPS: listens & talks (2 lines of each) RADAR: listens & talks navtex: listens only autopilot: listens only flowscan: listens only VHF listen/talk Navtex, Autopilot & flowscan need to listen to the gps radar & gps need to listen & talk to each other The VHF radio talks/listens to the gps. AIS receiver is in the budget & will need to talk to the gps & radar. From a few hours search; it seems I need multiple-multiplexers to make this work "correctly" -- can anyone give me a hand? -josh I have a Ratheyon radar and a Garmin 128 GPS. I bougt a Sitex AIS standalone unit and it reads the data easily from the GPS - no multiplexor, just bare wires. regards Peter |
nmea - talkers - listeners and lessons learned.
On Tue, 15 Jul 2008 10:29:00 -0700, Josh Assing
wrote: When I got my second nmea device, i was excited -- "hook it up" the manual said -- support said "yes; you just hook up all the nmea out with nmea in of the other devices and visa versa" so I did. It appeared to work. however, since I have some weird things recently discovered, we've traced it down to the fact that the info I got was wrong; and my understanding of nmea was woefully weak. GPS: listens & talks (2 lines of each) RADAR: listens & talks navtex: listens only autopilot: listens only flowscan: listens only VHF listen/talk Navtex, Autopilot & flowscan need to listen to the gps radar & gps need to listen & talk to each other The VHF radio talks/listens to the gps. AIS receiver is in the budget & will need to talk to the gps & radar. From a few hours search; it seems I need multiple-multiplexers to make this work "correctly" -- can anyone give me a hand? -josh One Very Important Rule: you can only have _one_ "talker" on an NMEA circuit, but can have several listeners. It looks like you will need a multiplexer to combine the GPS, Radar and VHF output data into one talker feed that everything listens to. (but you may have problems if something repeats everything it hears, as well as sending its own data - there are some intelligent muxes that can filter data to prevent this causing a problem) Note that normal NMEA-0183 data is sent at 4800 baud, while AIS data is normally sent at 38400 baud - they can't coexist on the same circuit. My Raymarine C80 chartplotter/radar display can accept AIS data at 38400 on its serial port, while the GPS and other NMEA-0183 data goes into the SeaTalk system via a Raymarine NMEA=SeaTalk interface box. -- Peter Bennett, VE7CEI peterbb4 (at) interchange.ubc.ca GPS and NMEA info: http://vancouver-webpages.com/peter Vancouver Power Squadron: http://vancouver.powersquadron.ca |
nmea - talkers - listeners and lessons learned.
Herodotus wrote:
... I have a Ratheyon radar and a Garmin 128 GPS. I bougt a Sitex AIS standalone unit and it reads the data easily from the GPS - no multiplexor, just bare wires. I have several GPS units that _talk_ to a laptop running Capn 8.3 and to a Furuno radar display. The GPS units are wired so that the output can be switched from one unit to the next, permitting only one _talker_ on the circuit (i.e., NMEA 0183 compliant). The GPS units can also be switched to bypass the laptop and _talk_ directly to one of several autopilots, and to the Furuno when the laptop is not in use (e.g., offshore passages). I like electronic toys and now want to add an AIS receiver (looking at the Smart Radio models) since Capn 8.3 is able to receive and display AIS information. I think I "get" the wiring requirements for the AIS, but am puzzled by one aspect: does the AIS receiver need an _additional_ GPS data source if I am already supplying GPS data to Capn 8.3. In other words, if Capn 8.3 is getting GPS sentences from, say, the Garmin GPS, and I somehow feed it the sentences from the Smart radio, will these data be combined to achieve the desired outcome, the display of AIS information on the Capn 8.3 chart display? Hope this question is not too poorly put. -- Good luck and good sailing. s/v Kerry Deare of Barnegat http://home.comcast.net/~kerrydeare |
nmea - talkers - listeners and lessons learned.
"Armond Perretta" wrote in message . .. I like electronic toys and now want to add an AIS receiver (looking at the Smart Radio models) since Capn 8.3 is able to receive and display AIS information. I think I "get" the wiring requirements for the AIS, but am puzzled by one aspect: does the AIS receiver need an _additional_ GPS data source if I am already supplying GPS data to Capn 8.3. In other words, if Capn 8.3 is getting GPS sentences from, say, the Garmin GPS, and I somehow feed it the sentences from the Smart radio, will these data be combined to achieve the desired outcome, the display of AIS information on the Capn 8.3 chart display? No, I think you got that a bit wrong. Here is the setup I use: GPS output input SR161 AIS Receiver output input PC (combined AIS/GPS data at 34,600 Baud). |
nmea - talkers - listeners and lessons learned.
Armond,
I have almost the same set up as do you. I have installed a Brookhouse multiplexer so that I do not have to switch NMEA talkers on and off. The GPS(Furuno 7000), Autopilot(Simrad Robertson AP20 with 3000x box), and the fathometer (Furuno RD30 with Airmar transducer) all feed into the multiplexer. The multiplexer then feeds out to the GPS, Radar Position (Furuno 1721M2), Radar Compass, Autopilot, & Depth and the computer. The AIS receiver(Milltech SR161 with antenna splitter) I feed straight into the computer with the Cap'n software. The computer get GPS data from the multiplexer and AIS data from the AIS receiver. It all works great. I believe that Milltech now has a multiplexer that will handle the AIS data but I have had mine for a few years. Cheers Ansley Sawyer SV Pacem |
nmea - talkers - listeners and lessons learned.
On Jul 16, 7:53*am, "claus" wrote:
... No, I think you got that a bit wrong. Here is the setup I use: GPS *output input SR161 AIS Receiver output input PC (combined AIS/GPS data at 34,600 Baud). AFIK, the SR161 needs the gps so it knows what the packet timing will be. This might help: http://www.milltechmarine.com/images...ate-Wiring.pdf -- Tom. |
nmea - talkers - listeners and lessons learned.
Ansley W. Sawyer wrote:
... I have almost the same set up as do you. I have installed a Brookhouse multiplexer so that I do not have to switch NMEA talkers on and off. The GPS(Furuno 7000), Autopilot(Simrad Robertson AP20 with 3000x box), and the fathometer (Furuno RD30 with Airmar transducer) all feed into the multiplexer. The multiplexer then feeds out to the GPS, Radar Position (Furuno 1721M2), Radar Compass, Autopilot, & Depth and the computer ... I think I am getting somewhere now thanks to your explanation, but still a few questions. Why first feed GPS info into the multiplexer, than out from the multiplexer back to the GPS? To allow route and waypoint uploads to the GPS? ... The AIS receiver(Milltech SR161 with antenna splitter) I feed straight into the computer with the Cap'n software. The computer get GPS data from the multiplexer and AIS data from the AIS receiver. It all works great. This is I believe the question I am trying to address. Are you saying that by feeding GPS data and AIS data _separately_ into Capn 8.3, they are combining in the Capn software to properly display AIS info on the chart? -- Good luck and good sailing. s/v Kerry Deare of Barnegat http://home.comcast.net/~kerrydeare |
nmea - talkers - listeners and lessons learned.
Armond Perretta wrote: Ansley W. Sawyer wrote: ... I have almost the same set up as do you. I have installed a Brookhouse multiplexer so that I do not have to switch NMEA talkers on and off. The GPS(Furuno 7000), Autopilot(Simrad Robertson AP20 with 3000x box), and the fathometer (Furuno RD30 with Airmar transducer) all feed into the multiplexer. The multiplexer then feeds out to the GPS, Radar Position (Furuno 1721M2), Radar Compass, Autopilot, & Depth and the computer ... I think I am getting somewhere now thanks to your explanation, but still a few questions. Why first feed GPS info into the multiplexer, than out from the multiplexer back to the GPS? To allow route and waypoint uploads to the GPS? ... The AIS receiver(Milltech SR161 with antenna splitter) I feed straight into the computer with the Cap'n software. The computer get GPS data from the multiplexer and AIS data from the AIS receiver. It all works great. This is I believe the question I am trying to address. Are you saying that by feeding GPS data and AIS data _separately_ into Capn 8.3, they are combining in the Capn software to properly display AIS info on the chart? That is correct. GPS data into COM1, AIS data into COM2. Is works great. The same think for Coastal Explorer. Hanz |
nmea - talkers - listeners and lessons learned.
Armond,
I send GPS data to the multiplexer which then sends it to the computer and to the radar and to the fathometer display (which is a multifunction display). This gives me position, COG, SOG, and waypoint info wherever I want it. I have the AIS and GPS entering the computer on two different ports due to the difference in baud rates and the data plots are great. My understanding of the new Brookhouse multiplexer is that it will combine AIS data with other data and send it all together. Check out this: http://brookhouseonline.com/pdf%20files/Mux_AIS_C.pdf Ansley Sawyer SV Pacem |
nmea - talkers - listeners and lessons learned.
"Peter Bennett" wrote in message news.com... Note that normal NMEA-0183 data is sent at 4800 baud, while AIS data is normally sent at 38400 baud - they can't coexist on the same circuit. My Raymarine C80 chartplotter/radar display can accept AIS data at 38400 on its serial port, while the GPS and other NMEA-0183 data goes into the SeaTalk system via a Raymarine NMEA=SeaTalk interface box. Peter, The SR161 can be used to consolidate incoming NMEA positional data from a GPS with the AIS NMEA data into a combined high-speed data stream on a single serial port. In that scenario there is no need for any multiplexer. |
nmea - talkers - listeners and lessons learned.
"claus" wrote in message . .. "Peter Bennett" wrote in message news.com... Note that normal NMEA-0183 data is sent at 4800 baud, while AIS data is normally sent at 38400 baud - they can't coexist on the same circuit. My Raymarine C80 chartplotter/radar display can accept AIS data at 38400 on its serial port, while the GPS and other NMEA-0183 data goes into the SeaTalk system via a Raymarine NMEA=SeaTalk interface box. Peter, The SR161 can be used to consolidate incoming NMEA positional data from a GPS with the AIS NMEA data into a combined high-speed data stream on a single serial port. In that scenario there is no need for any multiplexer. Forgot to add the link to the Wiring diagram for connecting a GPS into the AIS receiver using a Single Serial Port on the Computer: http://www.milltechmarine.com/images...ng-diagram.pdf |
nmea - talkers - listeners and lessons learned.
On Jul 18, 11:24*am, "claus" wrote:
"Peter Bennett" wrote in message news.com... Note that normal NMEA-0183 data is sent at 4800 baud, while AIS data is normally sent at 38400 baud - they can't coexist on the same circuit. *My Raymarine C80 chartplotter/radar display can accept AIS data at 38400 on its serial port, while the GPS and other NMEA-0183 data goes into the SeaTalk system via a Raymarine NMEA=SeaTalk interface box. Peter, The SR161 can be used to consolidate incoming NMEA positional data from a GPS with the AIS NMEA data into a combined high-speed data stream on a single serial port. In that scenario there is no need for any multiplexer. Right - just to clarify a couple of things: 1. AIS Receivers do not need GPS signals to output AIS sentences. They work independent of GPS. 2. With the SR161/SR162, you can feed GPS (or any other NMEA data) into the AIS receiver at 4800 baud on pin 3 and the receiver will combine the data with the AIS sentences and output the combined datastream out the single serial port at 38400 baud on pin 2 with a common ground on pin 5. We sell a cable to do this and also include the wiring diagram to build your own. See: http://www.milltechmarine.com/images...ng-diagram.pdf Doug Miller Milltech Marine |
nmea - talkers - listeners and lessons learned.
On Jul 18, 11:48*am, Doug Miller wrote:
... Right - just to clarify a couple of things: 1. AIS Receivers do not need GPS signals to output AIS sentences. They work independent of GPS. 2. With the SR161/SR162, you can feed GPS (or any other NMEA data) into the AIS receiver at 4800 baud on pin 3 and the receiver will combine the data with the AIS sentences and output the combined datastream out the single serial port at 38400 baud on pin 2 with a common ground on pin 5. We sell a cable to do this and also include the wiring diagram to build your own. See:http://www.milltechmarine.com/images...ng-diagram.pdf Doug Miller Milltech Marine Cool. I'm in the market for an SR 161. Does it help the unit any to have a GPS feed or does it just pass the data through. I can imagine how the unit might take advantage of knowing the packet timing, but I don't know if does. -- Tom. |
nmea - talkers - listeners and lessons learned.
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nmea - talkers - listeners and lessons learned.
The SR161 can be used to consolidate incoming NMEA positional data from a
GPS with the AIS NMEA data into a combined high-speed data stream on a single serial port. In that scenario there is no need for any multiplexer. but how does it talk to other non-high speed nmea devices then? |
nmea - talkers - listeners and lessons learned.
"Josh Assing" wrote in message ... The SR161 can be used to consolidate incoming NMEA positional data from a GPS with the AIS NMEA data into a combined high-speed data stream on a single serial port. In that scenario there is no need for any multiplexer. but how does it talk to other non-high speed nmea devices then? The AIS only "talks" with either a)a PC with chart plotting software that can show AIS or b) directly to a chartplotter that can show AIS. For example, on our boat the SR161's combined output goes to a PC with Coastal Explorer software. In turn, Coastal Explorer and the PC outputs NMEA (4800 Baud) to our Raynav Chartplotter and from there to all other instrumentation onboard via RayMarine's proprietary Seatalk network. Hope this helps. If I could I would send you a diagram - but I don't have a scanner.... :-( |
nmea - talkers - listeners and lessons learned.
On Jul 18, 6:30*pm, " wrote:
On Jul 18, 11:48*am, Doug Miller wrote: ... Right - just to clarify a couple of things: 1. AIS Receivers do not need GPS signals to output AIS sentences. They work independent of GPS. 2. With the SR161/SR162, you can feed GPS (or any other NMEA data) into the AIS receiver at 4800 baud on pin 3 and the receiver will combine the data with the AIS sentences and output the combined datastream out the single serial port at 38400 baud on pin 2 with a common ground on pin 5. We sell a cable to do this and also include the wiring diagram to build your own. See:http://www.milltechmarine.com/images...ng-diagram.pdf Doug Miller Milltech Marine Cool. *I'm in the market for an SR 161. *Does it help the unit any to have a GPS feed or does it just pass the data through. *I can imagine how the unit might take advantage of knowing the packet timing, but I don't know if does. -- Tom. GPS does affect AIS perfofrmance but of course you'll need a GPS for your nav package in order to calculate collision information (e.g. distance from you, closest point of approach and time to closest point of approach). |
nmea - talkers - listeners and lessons learned.
On Jul 19, 10:38*am, Josh Assing wrote:
The SR161 can be used to consolidate incoming NMEA positional data from a GPS with the AIS NMEA data into a combined high-speed data stream on a single serial port. In that scenario there is no need for any multiplexer. but how does it talk to other non-high speed nmea devices then? Basically you can take any inbound NMEA data stream or combined datastreams at 4800 and the SR161 will combine that data with the AIS data and output the combine original and AIS data streams on a single outbound port. It is only for inbound data. You can't have two way communication to the original NMEA devices - just an inbound feed to the AIS receiver from the NMEA data stream. |
nmea - talkers - listeners and lessons learned.
On Jul 20, 8:59*am, Doug Miller wrote:
... GPS does affect AIS perfofrmance but of course you'll need a GPS for your nav package in order to calculate collision information (e.g. distance from you, closest point of approach and time to closest point of approach). Thanks for that. Just to be clear, I have GPSes on my system and the computer that will run my AIS software already has GPS positioning data. What I think you are saying is that I should route one of the GPSes through the SR161 when I install it to make the 161 work better. Is that right? Cheers, -- Tom. |
nmea - talkers - listeners and lessons learned.
On Sun, 20 Jul 2008 09:02:35 -0700 (PDT), Doug Miller
wrote: On Jul 19, 10:38*am, Josh Assing wrote: The SR161 can be used to consolidate incoming NMEA positional data from a GPS with the AIS NMEA data into a combined high-speed data stream on a single serial port. In that scenario there is no need for any multiplexer. but how does it talk to other non-high speed nmea devices then? Basically you can take any inbound NMEA data stream or combined datastreams at 4800 and the SR161 will combine that data with the AIS data and output the combine original and AIS data streams on a single outbound port. It is only for inbound data. You can't have two way communication to the original NMEA devices - just an inbound feed to the AIS receiver from the NMEA data stream. I found that neither of my navigation programs (Ozi Explorer and Tiki Navigator) could handle the combined NMEA/AIS signal from the SR161 - or more correctly, they couldn't be set to accept both NMEA and AIS on the same serial port. I understand that some other nav programs will accept the combined data. -- Peter Bennett, VE7CEI peterbb4 (at) interchange.ubc.ca GPS and NMEA info: http://vancouver-webpages.com/peter Vancouver Power Squadron: http://vancouver.powersquadron.ca |
nmea - talkers - listeners and lessons learned.
On Jul 20, 5:03*pm, Peter Bennett wrote:
On Sun, 20 Jul 2008 09:02:35 -0700 (PDT), Doug Miller wrote: On Jul 19, 10:38*am, Josh Assing wrote: The SR161 can be used to consolidate incomingNMEApositional data from a GPS with the AISNMEAdata into a combined high-speed data stream on a single serial port. In that scenario there is no need for any multiplexer. but how does it talk to other non-high speednmeadevices then? Basically you can take any inboundNMEAdata stream or combined datastreams at 4800 and the SR161 will combine that data with the AIS data and output the combine original and AIS data streams on a single outbound port. It is only for inbound data. You can't have two way communication to the originalNMEAdevices - just an inbound feed to the AIS receiver from theNMEAdata stream. I found that neither of my navigation programs (Ozi Explorer and Tiki Navigator) could handle the combinedNMEA/AIS signal from the SR161 - or more correctly, they couldn't be set to accept bothNMEAand AIS on the same serial port. *I understand that some other nav programs will accept the combined data. -- Peter Bennett, VE7CEI * peterbb4 (at) interchange.ubc.ca * GPS andNMEAinfo:http://vancouver-webpages.com/peter Vancouver Power Squadron:http://vancouver.powersquadron.ca One solution I have recommended to folks with this issue that works quite well is to use something like GPSGate (http://www.gpsgate.com/ index.php?id=13) to take the input from a real serial port and duplicate it onto two virtual serial ports. Then connect each of the virtual serial ports to your nav software. For example, I believe you need to do this with MaxSea. Also would be a good idea to give feedback to the nav program authors that they should support multiple data streams on one port since this issue will also come up if you use a multiplexer to consolidate NMEA data streams. Doug Miller |
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