NMEA Pro Omnibus — $15U.S.

We have all our navigation equipment at the pedestal except for AIS (Vesper Marine)  and XM Satellite Weather. Both devices output data via USB. For about $300 we might be able to port the AIS data directly to our pedestal via our Ethernet backbone. However, we’d need an additional $500+ display as the chartplotter is nine years old, and is set up for MARPA. AIS was not broadly available then. There is no room at the pedestal for another display even if we could get the data there.

AIS Display

AIS DISPLAY

Another $300 might be required to multiplex this AIS NMEA 0183 data stream at 38400 baud with the NMEA 0183* data that already flows on the Ethernet backbone at 4800 baud. This might or might not work (The multiplexer device tech data says yes, users have told me sometimes.).

The XM data format is proprietary, and next I’ll be trying to figure out how to port it to multiple devices. It isn’t essential to do so since it is a long baseline planning tool — except when doppler radar loops are involved.

We were disinclined to spend ~$600 on a maybe solution.

As a result of our need, then desire, to stay connected, we have second backbone. It is wireless. We have a boosted antenna on the davits connected to a USB-powered router below — any wireless enabled device on the boat, laptop. reader, smartphone (cellular off) can connect from anywhere. So the challenge became to move the AIS data/information to the cockpit at low cost.

Wireless AISStep one was to move the USB delivered NMEA data to the wireless backbone (using TCP/IP). This requires a server — it’s what servers do. We already had one. It is part of the Rose Point Coastal Explorer software. But this software is a memory hog on the 12 year old IBM X-40 I use in the nav station. I didn’t want to have it running because it interferes with the weather software smoothly updating. So I found GPS Software for Google Earth — by Greg Heppenstall. $15 via PayPal later and I had a smoothly functioning server on the X-40 and a similar client on the environmentally protected laptop in the cockpit.**

Because I also use a piece of navigation software that can only accept NMEA 0183 via a COM port, we needed to find a software solution for binding a virtual comm port on the cockpit laptop to the wireless backbone. I found the HW-VSP3 software (free for single port, personal use).  While this must be reset each time it is used, it takes seconds, and free is a good price for something tested in a demanding market.

OPENCPN

SOFTWARE DISPLAY

So now all our AIS data/information and anchor watch data is available anywhere on the boat*** as long as the router is functioning. So it’s time for a spare router ($19 when we bought the first one, now $27. Still a bargain).

Total tab with spare router = $42. Much better than $600.

*Yes we know, NMEA 2000 has arrived. But it is expensive to retrofit, requires special cabling and connectors, and is aimed at a segment of the market that needs its feature set — we don’t, and a huge number of boats never will, and NMEA 0183 will hang around for decades.

** We are not fans of smartphones or tablets in sailboat cockpits. For those who navigate from environmentally protected spaces and who have the time and navigation space to squint at tiny screens with sun dilution, they may be useful. Having said that, when in network coverage, we have benefited from these devices (mostly doppler radar displays). We just have no interest in relying on them or making them the centerpiece of our situation awareness. If others want to use them, fine, as long as they don’t contribute to accidents.

***Even the TV, as it can be connected to the laptop via HDMI or S-Video, and we are looking at how to port low data rate imagery (weather and nav) to the TV via wireless. Also, since we have the boosted antenna on the boat, it may be possible to get the AIS/Anchor watch data to a portable device when we leave the boat.

One response to “NMEA Pro Omnibus — $15U.S.

  1. Pingback: AIS Now Being Served In The Cockpit (sans wires) | Periodically Peregrine

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