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I have an old japan radio company sounder with gps input and a laptop with cmap installed. Currently able to send NMEA data to laptop via usb to serial cable. using hyperterminal I am able to get the following nmea output strings from the com port. Are these NMEA strings and should Cmap be able to read them?
$SDGLL,4253.21,S,14719.76,E,,
$SDVTG,327,T,313,M,01.1,N,,
$SDBWC,003355,4259.91,S,14723.22,E,,,145,M,007.1,N ,0000
$SDRMB,A,2.53,L,0000,0000,4259.91,S,14723.22,E,007 .15,159,-01.0,V*12
$SDDBT,0013.4,f,0004.1,M,002.2,F
$SDMTW,14.5,C,58.1,F
$SDVHW,327,T,313,M,00.0,N,,
$SDAPB,A,A,2.53,L,N,V,,346,M,0000,145,M,,
$SDAPA,A,A,2.53,L,N,V,,346,M,0000
$SDRMC,003355,A,4253.21,S,14719.76,E,01.1,327,2308 89,14,E*68

Have tried setting cmaps config.exe - "nmea config tab" to gps-com4-RMC and numerous other different combinations but on opening cmap no lat/long is displayed, if I unplug com port then try to open cmap says unable to open port so cmap is seeing the port and I know the data in above format is being input to com port (com port settings are correct ie baud at 4800,8,1 etc). Ready to jump overboard, any help greatly appreciated.
Regards
Rubes
 

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Wandering Aimlessly
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22,037 Posts
You say your sounder has a GPS input, but not the source of the GPS data. You could be having proprietary issues. between the GPS reciever and the sounder.

The solution I would suggest is having a separate GPS reciever. For less than $40 you can get a "hockey puck" reciever with a USB end that plugs directly into your laptop. It requires no separate power, and will work from inside the cabin. It's what I use with my laptop and chart program. If you're interested you can check it out: Globalsat BU-353 USB GPS Receiver, BU353
 

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Telstar 28
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The problem is that those aren't NMEA data sentences from what I'm seeing... Look at this website, and you'll see that the prefix is all wrong.
The NMEA sentence for lat/lon is GLL and looks like this:

$GPGLL,4916.45,N,12311.12,W,225444,A,*1D

What your sounder is putting out for Lat/Lon is this:

$SDGLL,4253.21,S,14719.76,E,,

Whatever you're connected to is putting out data sentences, but they're not NMEA 0183 data sentences. So your software isn't going to recognize the data regardless of what you do. If you can see the data in Hyperterminal and you have the port set to 4800 8 N 1, your laptop is receiving it just fine.

Save yourself a lot of headaches and get a GPS receiver like that PBZ has recommended.
 

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GPS receivers are so cheap now, so its good idea to buy brand new unit. There are really interesting new solar-powered blue-tooth GPS units available now from different brands. Autonomous and wireless, quite handy. If You prefer lower price and less technology risk, You'd like to buy some <100 U$ USB GPS, sold in every pc shop.
 

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You could try GPSBabel to decipher those strings. It's a free, open source program. A list of formats it can translate are at GPSBabel: file format capabilities

But like a lot of open source programs, it's not particularly user friendly, and the documentation is lacking. Probably the easiest thing is do like PBzeer says and get a hockey puck for $40.

Scott
Gemini Catamaran Split Decision
 

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I have an old japan radio company sounder with gps input and a laptop with cmap installed. Currently able to send NMEA data to laptop via usb to serial cable. using hyperterminal I am able to get the following nmea output strings from the com port. Are these NMEA strings and should Cmap be able to read them?
$SDGLL,4253.21,S,14719.76,E,,
$SDVTG,327,T,313,M,01.1,N,,
$SDBWC,003355,4259.91,S,14723.22,E,,,145,M,007.1,N ,0000
$SDRMB,A,2.53,L,0000,0000,4259.91,S,14723.22,E,007 .15,159,-01.0,V*12
$SDDBT,0013.4,f,0004.1,M,002.2,F
$SDMTW,14.5,C,58.1,F
$SDVHW,327,T,313,M,00.0,N,,
$SDAPB,A,A,2.53,L,N,V,,346,M,0000,145,M,,
$SDAPA,A,A,2.53,L,N,V,,346,M,0000
$SDRMC,003355,A,4253.21,S,14719.76,E,01.1,327,2308 89,14,E*68

Have tried setting cmaps config.exe - "nmea config tab" to gps-com4-RMC and numerous other different combinations but on opening cmap no lat/long is displayed, if I unplug com port then try to open cmap says unable to open port so cmap is seeing the port and I know the data in above format is being input to com port (com port settings are correct ie baud at 4800,8,1 etc). Ready to jump overboard, any help greatly appreciated.
Regards
Rubes
Don't jump YET.
set in Cmapecs.ini, where your charts are on the HDD eg where is the CM93 directory... mine in on F drive as per following lines
--------------------------------
[DIRECTORY]
CM93ROOT=F:\CM93
CM93CAT=F:\CM93
CM93CHRLIST=F:\CM93
-----------------------------------
If yours is on C:\ change F to C ( NO GAPS IN THESE LINES!!)
Got it?
 

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Sea Slacker
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This is a perfectly compliant NMEA, however just because it is compliant does not mean every product will understand it. There are great many poorly designed NMEA listeners and other products out there.

The NMEA geographic position sentence is GLL. The first two letters in any NMEA sentence denote the type of the device that is producing it. GP generally means GPS. SD is actually a "depth sounder" so you would not necessarily expect it to send a GLL, but really a compliant NMEA processor should accept GLL from any device. (PolarCOM does :) ).

The rest of this sentence is just fine. It does not contain an optional time and status and there is no checksum, but that's optional too.

A decent reader would parse that sentence just fine. Old CMAP program (if that is the same one that made circles on P2P years ago) is not something that anyone should be using for navigation anymore. It has outdated charts, is fairly poorly written (in particular for modern day standards) and in any case - it is unlikely that anyone having it today has a proper license. But that's neither here nor there.


The problem is that those aren't NMEA data sentences from what I'm seeing... Look at this website, and you'll see that the prefix is all wrong.
The NMEA sentence for lat/lon is GLL and looks like this:

$GPGLL,4916.45,N,12311.12,W,225444,A,*1D

What your sounder is putting out for Lat/Lon is this:

$SDGLL,4253.21,S,14719.76,E,,

Whatever you're connected to is putting out data sentences, but they're not NMEA 0183 data sentences. So your software isn't going to recognize the data regardless of what you do. If you can see the data in Hyperterminal and you have the port set to 4800 8 N 1, your laptop is receiving it just fine.

Save yourself a lot of headaches and get a GPS receiver like that PBZ has recommended.
 
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