Help wiring DSC radio to GPS???

Waterman · 17 January 2008, 21:04

Anyone ever wire up a DSC VHF radio to their GPS???

I need to figure out which way to wire up the TX and RX wires on the NMEA connector.
Connection on the DSC looks like this

So Guess I need to wire the NMEA wires to something like this

This is the wiring diagram from the GPS. So does anyone know which way the TX and RX (NMEA in and out) should be wired to the phono type connector????????

DJL · 17 January 2008, 21:13

I'd use Com 1 on the GPS.

Connect the blue wire (Com 1 TX) to the centre pin on the phono, ground to the sleave.

Waterman · 17 January 2008, 21:53

Cheers,
I would have thought it needs both TX and RX???? Com2 White Rx and Green Tx??? but which way round??

captnjack · 17 January 2008, 22:04

Nope just one Tx wire (the blue one "out") from the GPS going "in" to the radio. Then hook up the grounds.

jwalker · 17 January 2008, 22:26

It depends on your radio and GPS. From your diagram it appears to be a Garmin unit.

Is the red phono connector of the radio the only NMEA connector it has? If so, DJL and captnjack are correct. You can connect either comm 1 or comm 2 TX to the centre of the red phono and a ground from the Garmin (usually battery negative) to the outer of your red phono connector. This will send position data to your radio. Your radio does not need to communicate with the GPS so the Rx can be left open. I guess the easiest way is for you to source a male phono connector and solder it to the GPS cables.

However, if you've also got a second NMEA connector for Tx from your radio, this will connect to the Rx on the GPS. The purpose of this is to show on your GPS screen the position of a contact on your radio.

Both the radio and the GPS must have this facility for it to work.

Edit: I've just looked very carefully at your diagram and it appears that Garmin are recommending you connect your DSC VHF to comm 2. It doesn't indicate that it is TX only so maybe your Garmin unit can accept data from your radio. Read the manual to find out.

Waterman · 17 January 2008, 22:53

Thanks all,
JWalker- that seems to answer my question. Cheers.- Manual is very vague as regards this area but think Ill go for the Com2/1 Tx and a ground. (can always use a bit of trial and error if it doesn't work)

Erin · 18 January 2008, 15:51

Yep the Garmin's normally take a RX as well so that a DSC received by the VHF can be shown on screen with the position of the calling boat.

Waterman · 19 January 2008, 15:07

So for this set up would I solder the Tx to the center pole of the phono connector and the Rx and ground to the outside???

jwalker · 19 January 2008, 16:27

Quote:

Originally Posted by Waterman

So for this set up would I solder the Tx to the center pole of the phono connector and the Rx and ground to the outside???

No. Tx to centre and ground to outer. To pass information from your radio to your GPS, the radio needs to have a separate Rx connector. Then you would connect Rx to centre and ground to outer of that connector.

jwalker · 20 January 2008, 19:05

Quote:

Originally Posted by jwalker

To pass information from your radio to your GPS, the radio needs to have a separate Rx connector. Then you would connect Rx to centre and ground to outer of that connector.

Oops, that should be: the radio needs to have a separate Tx connector.

Jon Brooks · 21 January 2008, 09:38

Also be sure to turn on the NMEA output on the Garmin unit.
Out of the box the unit will be set to send "Garmin" and not NMEA.

You will need to be sure that if it is an Icom set that you have a common earth for both the radio and the GPS.

With regard to displaying "Distress" and "Position Resquest" calls, not all Icom units send this info.
Only the M505 and M603 in the current line up do.

This function will work on all Garmin and or Standard Horizon plotters.

BTW all the current SH radio's send this info.

Cheers