Help please - can't get Cobra radio to display position!

Otter

Otter

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This is driving me nuts!!!

I've got a new Cobra F57 VHF radio, it's replacing an old Cobra, the old one displayed position. It gets GPS from the Matsutec AIS transceiver which sends NMEA position to a bus from which the Raymarine system gets position data - all working fine.

The Cobra comes with a plug with three wires, NMEA in +&- and a ground/shield but the manual shows a plug with only two wires and the Jack part only has one ring, this one has two.

I have the old Cobra NMEA in plug.

1. If I use the new plug, wired correctly it screws up the bus, nothing gets NMEA, with or without grounding the shield wire.
2. If I use the old plug that also sometimes screws the bus, sometimes not, either way neither plug gets the radio to display GPS.

Now I'm remembering my old Garmin days where they used three wires, didn't you have to join the NMEA - to ships negative 12v? But the manual is clear, you have a two wire NMEA system on this radio.

Anyone able to help? I thought NMEA was the one flipping part of the boat I understood :(
 
Just a thought, make sure shorepower is off when trying to connect, as the levels at which NMEA operate can be brought outside the parameters if the batteries are very highly charged,or there is ripple in the charge currrent.
May be a useless bit of info but my computer running a nav program will not display the ship's position until this is done.
Good luck with it!
 
I have a Matsutec HP-33A feeding an older Cobra, and the radio is very fussy about which NMEA output it will accept. It won't take the standard "GPS" sentence but will take "REM1" (may be "REM2"). This puzzles me, as both contain the standard GGA position+accuracy sentence at 4800baud. See HP-33A manual p10-4.

As far as wiring goes, page vii of the manual should reveal all, I think: pins 3, 4 and 5 are Tx, Rx and GND respectively and so I think they should be wired to tip ring, next ring and long bit of the Cobra plug.
 
Mrnotming said:
Just a thought, make sure shorepower is off when trying to connect, as the levels at which NMEA operate can be brought outside the parameters if the batteries are very highly charged,or there is ripple in the charge currrent.
May be a useless bit of info but my computer running a nav program will not display the ship's position until this is done.
Good luck with it!
Click to expand...

JumbleDuck said:
I have a Matsutec HP-33A feeding an older Cobra, and the radio is very fussy about which NMEA output it will accept. It won't take the standard "GPS" sentence but will take "REM1" (may be "REM2"). This puzzles me, as both contain the standard GGA position+accuracy sentence at 4800baud. See HP-33A manual p10-4.

As far as wiring goes, page vii of the manual should reveal all, I think: pins 3, 4 and 5 are Tx, Rx and GND respectively and so I think they should be wired to tip ring, next ring and long bit of the Cobra plug.
Click to expand...

Thanks both, now tried those and no joy.
 
My Cobra is fussy about the version of nmea it uses. From memory, we had to select v 1.2 or perhaps 2.1. I'm away from the boar, where the machine, its gps and handbook are currently situated. I suggest trying different versions in settings from the gps. If you have a really old gps, as I had, bite the bullet and buy a modern hh to interface with your new radio.
 
The Matsutec is wired the right way - the Raymarine units show GPS info. Def at 4800 baud. It's such a weird issue.
 
* If the plug is different from the manual, is it possible you have the wrong lead? You'd need to ask Cobra.

* Have you set the radio to INT/EXT GPS?

* Have you entered the MMSI number? Many radios won't work properly until the MMSI is programmed.

* Have you tried with the transponder set to output REM1, REM2 and GPS?

* Have you tried both of the NMEA type settings on the transponder?
 
Thanks Pete, I've tried all those except the radio set to int/ex GPS. I've looked in the manual for the F57 and can't find that, are you familiar with the radio?
 
While not trying to ask a silly question, have you got the NMEA + - wires round the right way. I've fitted a fair few of these and the wiring instructions in the manual is wrong, there should have been a small yellow piece of paper with an addendum to the instructions. If I remember I think instead of yellow for + and green for -, it green for + and yellow for -.
 
OK, so the Raymarine bits show GPS data coming from the Matsutec. But the Cobra radio doesn't. Perhaps the Cobra radio is faulty - why not try sending it back?
 
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