Electronics

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I guess that you'd expect a Radio Engineer to have the latest electronic gadgets to occupy her.

NMEA distribution

This seemed to be a major headache - getting NMEA from all the relevant kit that gives out data in NMEA format, and piping that into the devices that need it. For instance :

You can imagine the wiring mess trying to connect all these instruments together. I initially decided to have a GPS NMEA bus to feed everything, using 9 way D-Types as a common connection. The PCB would provide power switching to two power groups - Instruments and navigation. This was a good first attempt but ultimately ended up with a minor wiring mess.

The new NMEA distribution will distribute NMEA from the plotter, and an optional low power GPS module, two power groups ( nav/inst ), navbus and a couple of spare for other NMEA connections. I'll move away from 9 way D-Types and use pluggable terminal blocks instead. I would like some NMEA buffering ( back to back MAX232s ) and debug LEDS flickering with the NMEA data. Using the 8084 plotter as the GPS source might be a problem on long passages because of the current drain. A GPS moule built into the interface board might be a better option. Optional link to GSM modem for position updates.

Instruments

After my experience of Navman marine 3100 series kit on my previous yacht 'Sanda', I was keen to change all my electronics to Navman ( or Northstar nowadays ) eventually.

One exception is the Echopilot Forward Looking Sonar ( FLS ), this gives an underwater view of the slope of the seabed ahead. To be honest, I've found it not much better than a standard 'fishfinder' display, but it might be more useful in deeper rocky areas other than the East Coast.

The Navman Wind 3100 came with a loose magnet in the direction indicator that was quickly reseated, but after a month or so use, the whole instrument has become faulty. I cannot tell if it is the display or the sensor that is broken, but the direction is random and the whole display shows dashes ( unplugged ) after a while. To be fixed once I am able to get to the top of the mast. I now have a topclimber.

The Navman 3100 repeater seemed to fail to receive NMEA from NMEA_input_1 and NMEA_input_2. I am now working with NMEA_input_3 only but this limits what I am able to display.

The Navman 8084 plotter also counts as an instrument in so much as it *can* measure depth and speed. I may add these sensors and ultimately remove the FLS ( ebay ), but worry about the power drain from having to have the 8084 on all the time. 350mA ( no backlight ) to 1A ( full backlight )

Navigation

I initially played with a 1.2GHz MiniITX PC and display for navigation, using EuroNav SeaPro 3000 software. It felt a little 'clunky' and the combined PC and display took over 3A. The second option was to use a Navman 8084, and this ( so far ) feels much smoother

The Navman 8084 takes C-Map SD cards, and I bought the UK Megawide Max charts

A NASA AIS is used, together with a VHF whip on the pushpit, to receive AIS transmission from local heavy shipping. This data is then sent to the 8084 plotter for display where each ship is shown with details, track and collision alarms. Here are details of how to connect a Navman 8084 plotter to a NASA AIS black box.

Autopilot

Radio

Navman DSC VHF radio with external handset position in the cockpit. VHF halfwave whip at the top of the mast - to be checked.

Amateur Radio 100w HF 1.8-30MHz into an SGC ATU and insulated backstay as a radiator.

Power

Connections

Navman 8084 Plotter

Power connector

Accessory cable

Navman VHF 7000, 7100,7200

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