Connecting Navman VHF 7100 to Garmin GPS 72

[Achillesheel]

I'm fairly sure this has been covered before, but I am trying to connect my GPS to my VHF.

The GPS cable has:- Brown, Black, White, and Red with a fuse.

The VHF has:- Grey, Blue, Orange, Black, Green marked GPS-, Yellow marked GPS+, and a bare wire. There is also a separate Black & Red from the VHF for the power.

I have found a Plastimo/Navman diagram on the web but find it incomprehensible.

I'm sure someone must have the same combination as me, and any help would be gratefully accepted.

 

[Bru]

Did just this on Friday evening albeit between a Garmin 72H and a Standard Horizon VHF

On the GPS cable ..

Red = +ve
Black = Ground
Brown = Data out
White = Data in

From http://www.plastimo.com/pdf/VHF_GPS_interface_en.pdf ...

You need to connect the green GPS - wire on the radio to ground (negative) and the yellow GPS + wire on the radio to the brown Data out lead on the GPS

That's it. Ignore all the other cables!

You also need to make sure that the GPS is set to use NMEA at 4800 baud in the setup page - by default it will probably be in Garmin interface mode

HTH

 

[elton]

You need to connect the green GPS - wire on the radio to ground (negative) and

Surely you mean "You need to connect the green GPS - wire on the radio to ground (negative) (black) from the GPS"?

 

[ssjpiv]

GPS

Hi, Just ambushing the post...... what cables did your 72H come with? I just got one on friday and it seemed to only include the charging cable thing.

If you bought one elsewhere, where did you source it?

Thanks

 

[Bru]

Surely you mean "You need to connect the green GPS - wire on the radio to ground (negative) (black) from the GPS"?

No, to the negative supply. Anywhere, it doesn't matter

The VHF has seperate power - and signal - wires, the GPS doesn't. So all you need to do is to connect the signal - at the VHF to the supply negative and you might as well do that at the back of the radio

 

[Bru]

Hi, Just ambushing the post...... what cables did your 72H come with? I just got one on friday and it seemed to only include the charging cable thing.

If you bought one elsewhere, where did you source it?

Thanks

You need the optional power/data cable. I got lucky and found one lurking on the shelf at Foxes in Ipswich but most likely you'll have to order one up (either on-line or via your favourite friendly chandler)

It is a Garmin specific product (it has the same 4 way plug at the GPS end as the supplied power cable but just bare wires at the other end)

 

[elton]

No, to the negative supply. Anywhere, it doesn't matter

The VHF has seperate power - and signal - wires, the GPS doesn't. So all you need to do is to connect the signal - at the VHF to the supply negative and you might as well do that at the back of the radio

But the GPS needs a ground connection (ultimately) as well as the signal connection to the radio. The data can't be sent through just one wire.

 

[Bru]

But the GPS needs a ground connection (ultimately) as well as the signal connection to the radio. The data can't be sent through just one wire.

Ahem, the GPS HAS a ground connection (the black wire). The VHF has a ground connection AND a signal ground

The signal IS sent through one wire (most signals are). You need a common reference (ground) which is the negative supply. It doesn't need to be explicitly connected via the signal cable provided both units are connected to the same supply and, in the case of the Navman, the signal ground connection is connected to the supply ground

You could, if you so desired, connect the signal ground wire on the radio to a second core in the signal cable (or the shield in a shielded cable) and connect to the supply negative at the GPS end. Electrically speaking it would make no difference whatsover (and shielding the NMEA signal cable would probably be fairly pointless as well - it's a very crude serial data stream at a low transmission rate and not particularly prone to interference)

 

[elton]

Ahem, the GPS HAS a ground connection (the black wire). The VHF has a ground connection AND a signal ground

The signal IS sent through one wire (most signals are). You need a common reference (ground) which is the negative supply. It doesn't need to be explicitly connected via the signal cable provided both units are connected to the same supply and, in the case of the Navman, the signal ground connection is connected to the supply ground

You could, if you so desired, connect the signal ground wire on the radio to a second core in the signal cable (or the shield in a shielded cable) and connect to the supply negative at the GPS end. Electrically speaking it would make no difference whatsover (and shielding the NMEA signal cable would probably be fairly pointless as well - it's a very crude serial data stream at a low transmission rate and not particularly prone to interference)

Yes, but in your initial reply to the OP, you said

You need to connect the green GPS - wire on the radio to ground (negative) and the yellow GPS + wire on the radio to the brown Data out lead on the GPS

That's it. Ignore all the other cables!

- which could be quite misleading, I think.

 

[Achillesheel]

Brigantia,

Many thanks for this, will give it a go next time we sail.

 

[Bru]

Yes, but in your initial reply to the OP, you said

- which could be quite misleading, I think.

Not if you follow the link to the Plastimo document on connecting the specific radio in question to a GPS, then what I said makes sense! Without looking at that document, I grant it could be confusing

For clarity ..

The (seperate) radio +Ve and -Ve supply connections need to be connected, via a suitable fuse on the +Ve to the 12v supply on the boat

Likewise, the (integral) GPS +12v (red) and Ground (black) connections need to be connected, also via a suitable fuse (one is supplied with the cable) to the 12v supply on the boat

The Signal (NMEA / GPS) - (green wire) on the VHF data cable needs to be connected to the negative side of the boat electrics. This can most easily and effectively be done by connecting it to the -Ve supply connection to the radio

The Signal (NMEA / GPS) + (yellow wire) on the VHF needs to be connected to the Data Out connection on the GPS (brown wire)

This leaves five other wires on the Navman data cable which do not need to be connected to anything. There is one redundant wire on the GPS cable (data in - white) which also does not need connecting to anything

That's the basic GPS to VHF wiring for the two bits of kit concerned

Not convinced that's actually any clearer but hoping it is!

 

[ssjpiv]

Thanks

Thanks for the information, cable ordered...