Nmea 0183 wiring for 2 gps "sources"

[alisdair4]

CLARITY

I'm pretty sure that there is more inside a multiplexer than a chocolate block, so they are hardly interchangeable. You can't join the two feeds, you need to switch between them.

Nigel,

to be clear. I know that I need to add a switch. I was talking about using a chocblock arrangement to join the various feeds ONCE they have been switched.

See the OP for my circuit diagram.

 

[nigelmercier]

I was talking about using a chocblock arrangement ...

You choice of course, albeit a bad one.

 

[nigelstgeorge]

Nigel,

to be clear. I know that I need to add a switch. I was talking about using a chocblock arrangement to join the various feeds ONCE they have been switched.

See the OP for my circuit diagram.

I do not see what is wrong with chocblocks provided one solders the wires together first before putting them in and in one wants a 'boots and braces' job then one can seal the whole chocblock in silicon to provide a fully waterproof/salt resistant connection.

I would be interested in what Nigel would do otherwise as crimp connectors are just as bad as chocblocks.

 

[nigelmercier]

I do not see what is wrong with chocblocks provided one solders the wires together first ...

So now you no longer have a chocbolok connection, you have a solder connection with a weight hanging on it to help the wires to break.

If you are going to solder the wires, then just twist together, solder, apply heat shrink.

 

[elton]

I do not see what is wrong with chocblocks provided one solders the wires together first before putting them in and in one wants a 'boots and braces' job then one can seal the whole chocblock in silicon to provide a fully waterproof/salt resistant connection.

I would be interested in what Nigel would do otherwise as crimp connectors are just as bad as chocblocks.

Gel connectors

 

[nigelmercier]

Gel connectors

Nasty IDC connectors with a bit of gel in them, no thanks.

 

[rob2]

There are a number of places on the boat where there is no significant risk of cable movement to strain a joint and no risk of water ingress unless you're sinking (like behind the instrument panel. I made my NMEA junctions by crimping ferrules to all the wires and connecting them with a choblock inside a box, but I have left a bight of each cable flaked out alongside so as to avoid any strain. The main problem with chocblocks I have found is that the wires can corrode in the salt atmosphere and the action of the screw often breaks the wire. The type with a plate to grip are better, but don't grip smaller wires so well. The crimped ferrules overcome these problems and can accomodate the wide variety of cable sizes to be joined. I consider this to be a good compromise when compared with trying to find suitable connectors for the range of wire sizes invloved, e.g. power feeds to some instruments (as large as can reasonably be fitted) and the GPS out which are thinner than my hair (and I'm nearly bald).

Rob.

P.S. use a proper ratchet crimp tool and insulated terminals if you use this method!

 

[nigelstgeorge]

So now you no longer have a chocbolok connection, you have a solder connection with a weight hanging on it to help the wires to break.

If you are going to solder the wires, then just twist together, solder, apply heat shrink.

I will agree with that - not everyone has heatshrink tubing available and ideally a proper heat shrink gun. Solder and heatshrink is the best.

BTW when we had to join a Brookes & Gatehouse multi-core cable instrument cable halfway down the mast I soldered and heat shrunk each wire then added two plastic cable ties either side of the join and then heat shrunk the whole lot for extra strength. So far some few years later the owner is overjoyed.