GPS connections

Albaman

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23 Jan 2004
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I have a Garmin 126 GPS and a M-Tech MT-500 DSC vhf radio. I want to connect them together so that the radio can transmit my position if I ever have to hit the distress button. Reading the respective manuals has left me baffled. Anyone out there know which colour cables go together please? /forums/images/graemlins/confused.gif
 
I've connected a Garmin GPSMAP 168 to a Raymarine DSC radio and have a word document with the connections. If you can't get it working, PM me and I'll send it to you. Don't know if it's the same, but you can have it if you want it.
 
You may also need to check that the GPS is setup to send and receive NMEA. (Garmin have a couple of other options on some chartplotters).

It is probably not worth connecting the NMEA out from the radio to the NMEA in on the GPS. This can, if supported by both radio and chartplotter show the position of a received DSC alert. I am not sure if this would work with your ket.

John
 
This is what I have, hope this works....
connection.jpg
 
In practice you can usually get away with feeding more than 3 devices from a single NMEA output. I curretly feed 4 from my GPS, but this may rise to 6.

John
 
I have connected the wires as you advise & checked the interface I/O setting on the GPS which is None/NMEA.

The radio works & the GPS works but they are not talking to each other.

The Garmin 126 GPS was on the boat when I bought it a couple of months ago. The radio is new, previously had a Silva but it let water in & stopped operating so I replaced it with the M- Tech MT500 DSC VHF.

I take it the "shield" is the bare wire? /forums/images/graemlins/confused.gif
 
Hello,

I have a Garmin connected to my Silva radio and a few other bits - the interface I think should be NMEA/NMEA.

As far as I can remember /forums/images/graemlins/tongue.gif the power does'nt matter (can come from anywhere) but you MUST connect the radio earth with the GPS earth - not just a common connection - no idea why but it won't work otherwise.
 
Albaman, I'm not familiar with your GPS, but mine has 2 ports, port 1 and port 2. You have to make sure that you have enabled the correct one. I did this by trying both - one of them worked.

By enabling, I mean setting the I/O setting, yes?
 
I have connected the cables & have tried different interface settings i.e. NMEA/NMEA & None/NMEA but the radio still says "No GPS" Am I missing something?
 
You seem to have the GPS set up correctly to send the correct data, and the radio set to receive it. The fault probably lies in the connection.

Can you test to see if here is a break in the wires between the plugs and ends. If these are okay - is the connection between the cables sound. If so, then my guess is that the fault lies in the earthing. You shouldn't actually need the Radio Gnd (Shield), so try:

GPS OUT (Blue) to Radio IN+ (Brown)
GPS Gnd (Black) to Radio IN- (Red)

If this doesn't work, then connect the Gnd(Shield) back in, and make sure it also connects to the Radio Earth lead.

John
 
I finally got it working. Apparently the BAUD setting on the Garmin GPS had to be 4800 & it was at 2400......anyway it's all good now, many thanks for your help. All I need now is some nice boating weather......a bit cold here in Shetland just now!
Cheers,
Dave.
 
Glad it all worked out - I didn't think you could change the baud rate on the garmin.

Weather not much better down south - couple of weeks ago swmbo refused to go onto the foredeck to pick up the mooring until I had cleared the ice away !!!

take care

John
 
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