Nasa sx 35 connection to garmin 451 chartplotter

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dave_b

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Hi anyone with any ideas how to connect sx 35 to garmin 451s ..no Vhf data cable but got an 8 pin plug from Maplins and tried connecting up directly from garmin but no joy...all ideas welcome...nasa have said try ebay for data cable no joy there either
 
So have you connected the NMEA output from the Garmin to pins 1 & 2 of the SX35? And have you configured the Garmin's port to output NMEA Standard?
 
As pvb says we need more info on what you have tried already.

As usual the garmin has a common ground. This means the negative wire of its power supply is also its NMEA negative. So you need to wire pin 1 of your VHF to either the blue (port 1 tx) or the grey (port 2 tx IF the plotter has a second port) wires of your garmin and pin 2 of your VHF to ground (ultimately the negative pole of the same battery that powers the garmin; usually this means to the electronics bus bar). Then you need to make sure the output port is set to standard NMEA/4800.

Over and above this, you might check that the unit actually outputs NMEA GPS sentences at all. I'm not familiar with the kit but the 400 series installation manual only gives a bunch of sentences relevant to depth and water speed in the list of NMEA0183 comms in the appendix. It would be unusual for it not to outputposition data but stranger things have happened.
 
Many thanks for your replies ..so far we have followed the instructions in manual to take blue to port 1..brown to port 3..and ground to port 4 ..all the sentences see to be correct ...but nothing ..not tried taking the ground to port 2 do I then leave brown to port 3.???
 
dave_b said:
Many thanks for your replies ..so far we have followed the instructions in manual to take blue to port 1..brown to port 3..and ground to port 4 ..all the sentences see to be correct ...but nothing ..not tried taking the ground to port 2 do I then leave brown to port 3.???
Click to expand...

If you are trying to get position sentences INTO the VHF then no that's not right as you have no circuit on the NMEA RX of the VHF without ground to pin 2.

Blue wire GPS to Pin 1 VHF
battery negative to Pin 2 VHF

That will complete your NMEA receive circuit for the VHF and- assuming the Garmin actually sends position sentences- you will get position on the VHF for DSC purposes.

Pins 3 and 4 are the VHF's NMEA transmit circuit. (Edited to add: Initially I doubted the plotter would receive DSC from the VHF but the manual suggests it might do. If you don't want DSC position alerts wiring this up is optional. You have it correct anyways but you are not going to see anything unless a DSC alert is received, and they are pretty rare in S Wales, so this might explain why it looks like nothing doing at the moment). Anyway:

GPS Brown to pin 3 VHF
Battery negative to pin 4 VHF

All this assumes you have powered up the Garmin by connecting its black wire to battery negative of course :)

Make sure your Garmin port is set to 4800 baud
If nothing is working after that I would check the Garmin is actually transmitting the sentences you need.
 
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dave_b said:
Many thanks for your replies ..so far we have followed the instructions in manual to take blue to port 1..brown to port 3..and ground to port 4 ..all the sentences see to be correct ...but nothing ..not tried taking the ground to port 2 do I then leave brown to port 3.???
Click to expand...

OK, try this...

* Garmin blue (Port 1 Tx out) to Nasa pin1
* Garmin brown (Port 1 Rx in) to Nasa pin 3
* Garmin black (ground) to Nasa pin 2 and to Nasa pin 4.
 
pvb said:
OK, try this...

* Garmin blue (Port 1 Tx out) to Nasa pin1
* Garmin brown (Port 1 Rx in) to Nasa pin 3
* Garmin black (ground) to Nasa pin 2 and to Nasa pin 4.
Click to expand...

You are correct here, but if they are both connected to the same power source he can just connect the NASA pins 2 and 4 to the NASA ground. Same thing as you suggest, possibly a bit less wiring.
 
PaulRainbow said:
You are correct here, but if they are both connected to the same power source he can just connect the NASA pins 2 and 4 to the NASA ground. Same thing as you suggest, possibly a bit less wiring.
Click to expand...

Of course, but one thing I've found on these forums is that some people have dedicated VHF batteries, hence my answer.
 
pvb said:
Of course, but one thing I've found on these forums is that some people have dedicated VHF batteries, hence my answer.
Click to expand...

Yup, hence my qualification that they need to be on the same power source :)

As an aside, these setups sometimes work without even connecting those ground wires, depends on the equipment.
 
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