Basic NMEA sanity check

[prv]

Possibly not very robust.

Tru dat, as they say. Mine got stove in while being shuffled around in its bag in the electronics drawer (nothing particularly heavy or pointy stowed therein) - before I'd even used it for a first job.

Pete

 

[dom]

The best tool for this is a logic probe, I wouldn't be without one on the boat: http://amzn.to/1rxaiIs

Instructions here: http://www.lasertools.co.uk/items/pdf/Products/5263_Instructions.pdf

Tks for that, I followed your link and immediately bought one! My DSC radio has lost its GPS input; so has my chartplotter, which now only works if I switch the Navtex on! That little probe should hopefully help me avoid aimless rewiring until I find the bad connection.

 

[nigelmercier]

... I followed your link http://amzn.to/1rxaiIs and immediately bought one! ... That little probe should hopefully help me avoid aimless rewiring until I find the bad connection.

One thing to note: try it on the CMOS setting first.

 

[lampshuk]

Couldn't resist temptation to go for the mini 'scope in the end.

Even though I figured out my problem was a poor connection I couldn't resist sticking the scope on the NMEA output.

Voila:



The Cobra DSC radio now springs to life and shows Lat Long.

Although, worryingly, it shows the Lat as being S rather than N.

Maybe I got the polarity of the connections wrong?

Or hopefully a firmware update is in order.

 

[oldgit]

I have an analogue multimeter on board. It's a long time since I needed to test any NMEA, but I think when I did the needle waggled around in a fairly distinctive way.

Pete

Any analogue or digital meter set to volts will waggle about enough to indicate a signal is present.
Tip told to me my the head teccy honcho of a very serious UK radio company well known for giving excellent repair service
to older marine radios .