Upgrading NMEA output on Philips AP Navigator

[Danny Jo]

This is one for the techno wizards: Freestyle has a 20 year old GPS unit called a Philips AP Navigator. When I bought the boat 2 years ago it was delivering an NMEA position signal to the (then) brand new Icom DSC radio, and position and SOG to a cockpit repeater. I could also get a bearing and distance to a waypoint provided that I entered the waypoint at the cockpit repeater. Faced with a series of waypoints in the form of a route, the AP Navigator could correctly calculate the the distance and bearings between them, but would make a pig's ear of calculating the whole route, by adding around 8,000 nm. And it resolutely refused to communicate a distance and bearing to next waypoint to the cockpit repeater. In desperation I resorted to an "ugly" reset (restoring the unit to the original factory settings) - this fixed the waypoint/route problem but created a new one: the Icom cannot understand the signal anymore. Worse still, my new AIS display can't understand the signal either.

The solution recommended by the nice marine electronics man is, of course, a new GPS unit with external aerial, a snip at 199.99 plus fitting. But Freestyle is already groaning under the weight of 5 or more assorted aerials, and the AP was clearly capable of delivering an intelligible NMEA signal before I so cruelly reset it. Looking through the sales spec, I see the line "Philips AP Navigator (updated 2002)", which update I suspect was a software upgrade. I have done a Google search for such an upgrade without success.

Any suggestions that don't involve adding further to the winter overspend (new genoa, AIS, isolation transformer, wind generator etc, etc) would be very gratefully received.

 

[Bilgediver]

Sounds like you might need to reset the nemea ports manually to the right speed for the dsc radio...
The NMEA 0183 Interface Standard specifies the communication settings as Baud Rate: 4800 Data Bits: 8 Parity: None Stop Bits: 1 (or more)

 

[pampas]

Have been into you settings and checked that update is ON and that the averaging is set to zero? When I istalled mine many years ago I found that the default settings for 1st time start up were not as descibed in the manual, after setting these two functions, the set operated correctly. Hope that this is of help. regarding software updates until Phillip gave up the production you could only get them updated at the dealers,now a different company supplies the bits they might well allow downloads over the nett.

 

[Danny Jo]

Many thanks to Bilgediver and Pampas. Bilgediver wrote [ QUOTE ]
Sounds like you might need to reset the nemea ports manually to the right speed for the dsc radio

[/ QUOTE ] The only options available in SETUP for configuring the ports are for choosing between NMEA ports (1 and/or 2), NMEA formats (0180 or 0183), CHKSUM on or off, and NMEA output sentences (present position on or off, steering heading command on or off, great circle or rhumb line routes, etc). Between us the nice electronics man and I must have tried every permutation 3 times over.

Pampas writes [ QUOTE ]
Have been into you settings and checked that update is ON and that the averaging is set to zero?

[/ QUOTE ] I haven't been able to find a screen that offers these options.

Google found this thread from 2005. I have emailed redcar-fish for advice.

 

[nigelmercier]

[ QUOTE ]
In desperation I resorted to an "ugly" reset (restoring the unit to the original factory settings) - this fixed the waypoint/route problem but created a new one: the Icom cannot understand the signal anymore. Worse still, my new AIS display can't understand the signal either.

[/ QUOTE ]

Are you able to plug the output into a PC?

 

[Oldhand]

A firm called Comar in W. Cowes were the experts on AP navigators, did repairs and software upgrades etc. However, they now seem to be totally AIS but no harm in conatacting them if you don't get a solution. http://www.comarsystems.com/

 

[Danny Jo]

[ QUOTE ]
Are you able to plug the output into a PC

[/ QUOTE ] I can't, but a man who knows how produced this

The AP Navigator was designed to output NMEA 0183 version 1.5. The ICOM VHF requires version 2.0 or above. What is frustrating is that it was delivering a readable output until I reset it. If I hadn't just managed to thread 5 metres of new gas pipe along the route followed by the old one I would be wondering if I'd lost my grip.

 

[Danny Jo]

Many thanks. The man at Comar Systems was indeed both knowledgeable and very helpful. I was wrong to conclude that I had wiped the machine's software update - the current version is the post-2000 one. My task is to find the option switch that will restore the output signal to the form it was before the reset (apparently the default is everything off).

There you are folks - time spent on Scuttlebutt saves us money (but don't tell YBW).

 

[nigelmercier]

[ QUOTE ]
[ QUOTE ]
Are you able to plug the output into a PC

[/ QUOTE ] I can't, but a man who knows how produced this

Ooooh! That's nice. How did he do that? I want one!

 

[Gypsy]

These are not good data waveforms. They should be a series of clean square/rectangular pulses going from 0-12V or 0-5V or -12-+12V. The voltage will vary according to the type of output circuit but they should all have fairly square tops and bottoms.

Firstly we can question the method of attaching the 'scope, it may have had a bad ground and therefore it is not really showing the output signal correctly. But are you sure there has been no physical change to the cabling? The waveforms suggest a bad cable or partial short somewhere. If it was software only, I would expect to still see clean data, it would just be in a format or sequence which was not suitable for the receiving device.

Just took another look at the waveforms. The 1st one shows an amplitude scale of 0.5v to -0.5v. This is into no load. It looks like it is just measuring noise. I would expect to see a good +/- 5v or more into no load and as mentioned above, a clean square wave. The 2nd waveform has an amplitude scale of +10to-10v and a signal of approx +/-3v but not well formed. Your NMEA Rx devices will be looking for 0vto+5v so they would struggle with even a clean signal at only 3v.