Newbie GPS Antenna Question

[ThereAndBack]

Please bear with a newbie in his struggle to begin understanding the complexities of navigation systems.

This Raytheon GPS antenna is fitted to my Bav 37. I guess it is the same age as the boat, about six years old.

I assume it to be model number E35009 (but I may be wrong). I also guess that it was originally supplied with my RN300 autopilot.

Can anyone tell me what type of data this antenna produces, NMEA, Seatalk or what?

My plan, if possible, is to connect it to a laptop so any advice on this is also welcome.

Answers please in layman's terms (as far as possible).

Thanks

Alan

 

[ccscott49]

If it's oldish, then it will be NMEA output.
But if I were dong it, I would buy a USB GPS, plugs straight into a USB port on your computer and does what it says on the box/book. Cheap as chips, 30 squids, solves all your problems in one.

 

[Silverado]

... and don't clip it to the rail like the one in the photo. Its a perfect target for breaking off with a warp or a misdirected grab. Bolt it at deck level, they work perfectly that way.

 

[raquet]

If it is an antenna (which it seems to be from its appearance) then its output is neither NMEA nor Seatalk. Its function is to provide a signal to feed a GPS device which will then have NMEA or Seatalk capability. Its like a radio antenna- in fact, it is a radio antenna, but a specialised one. As already suggested you can get a USB connect GPS for very little these days - even a Bluetooth connect which eliminates cables (if you have Bluetooth on your laptop).

 

[mainmarine]

You could try here, http://www.raymarine.com/raymarine/Default.asp?site=1&Section=3&Page=166&Parent=3
some Raymarine GPS's output seatalk and some nmea it should tell you in the manual.

 

[Oldhand]

I am confused becase a RN300 (Raynav 300) is a GPS and what you show in the picture looks like the antenna a RN300 is supplied with. If this is the case it can only be used with the RN300 GPS or the RC320 GPS/Plotter and the antenna neither gives NMEA or Seatalk output directly.

 

[davierobb]

As previous post say, buy a separate usb gps engine for your laptop, much easier and also gives you second independent gps system that can be move anywhere on the boat as its not tied to the output of your current gps. Ebay has such devices, I bought one for £15 and it works a treat.

 

[pvb]

And the answer is...

Gosh, what a variety of responses you've had. If you have a Raynav 300, it's a GPS, not an autopilot. The antenna supplied with it is an active antenna. The Raynav 300 outputs NMEA data, and you can link this to a laptop. The Raynav 300's power/data cable has a yellow wire, which you connect to pin 2 of a 9-pin serial connector; the white wire goes to pin 3; the green & brown wires both go to pin 5.

 

[sailorman]

the sea talk cable is a 3 core cable

the nema is 5 core

( Or have i been Lakesailored /forums/images/graemlins/mad.gif )

 

[ThereAndBack]

Thank you to everyone for the answers.

My understanding is as follows:

The antenna receives 'raw' data which the RN300 (GPS) interprets. The RN300 outputs this as nmea and seatalk (according to my manual). I can take the nmea output directly to my laptop.

Is that right so far?

If so, am I right in thinking that the laptop can then send waypoints (using nmea) to the RN 300 (to run the autopilot?

As before, answers in layman's terms will be appreciated.

Thanks

Alan

 

[Marmalade]

My raymarine gps mushroom is more than just an antenna and I suspect yours is too - it can feed a plotter, a binacle instrument etc. It puts a sentence on to the seatalk bus containing all the data you'd expect from a gps - ie position, heading, speed. Other instruments pick up these sentences and perform calculations to come up with, say, btw.

Previous poster, though, is right. Get a usb or bluetooth gps for your lappie.

 

[whipper_snapper]

[ QUOTE ]
Get a usb or bluetooth gps for your lappie.

[/ QUOTE ]

Can anyone suggest a USB (not bluetooth) GPS engine known to work without issues with Maxsea and Win XP?

I was disappointed to find that my Garmin 76CSX will not talk directly via USB to Maxsea. There are a number of ways of making it do this but all require me to buy hardware or software and I think I might as well buy a totally independent 'puck' GPS. But I don't want to find I still need extra stuff to make it work!


Thanks

 

[john_morris_uk]

[ QUOTE ]
My raymarine gps mushroom is more than just an antenna and I suspect yours is too - it can feed a plotter, a binacle instrument etc. It puts a sentence on to the seatalk bus containing all the data you'd expect from a gps - ie position, heading, speed. Other instruments pick up these sentences and perform calculations to come up with, say, btw.

Previous poster, though, is right. Get a usb or bluetooth gps for your lappie.

[/ QUOTE ]What you say is correct for the later model 'antennas' (which should read antenna and GPS receiver in one mushroom). However, if the one illustrated is for a Raymarine 300 GPS it is JUST THE ANTENNA that sends the 1.6 Ghz signal down the cable to the GPS receiver. This GPS receiver will supply Seatalk and NMEA outputs. I know this because we have one, and it sends data on our Seatalk bus as well as to the DSCVHF we have.

By the way, if you don't have/want a plotter the 300 is a great GPS.

 

[Guest]

I personally advocate a small Hand held GPS such as eTrex or similar .... for very good reasons :

a) GPs mouse is only useful if PC is on and powering it. Dead Pc = dead GPS mouse
b) HH GPS gives back-up independent machine that you can use completely on its own
c) Can be bought of e-bay for not much more than a GPS mouse.
d) Usually less hassle to connect to most chart plotting software.
e) Many are RS232 serial plug - so allow older cheapo notebook PC's to be used ... with conversion cable still useable on later USB only machines.

Yes the GPS Mouse is a good tool - but relies purely on PC being alive and well.

Onto the antenna on rail ........... most do actually output NMEA but you have to sort connection. The apparent NMEA output from Plotter is often a "feed-through" from that antena appearing to be plotter created.
Many plotters can actually have different manufacturers antena connected for data input ... based on NMEA. Like my Lowrance 3500 - I can choose either my eTrex or the LGC 2000 antena to feed data to plot.

Let's be honest if you were in biz of selling a system - are you going to tell your customer they can connect a 50 quid eTrex instead of a 200 quid proprietary antena ?

 

[john_morris_uk]

[ QUOTE ]
Onto the antenna on rail ........... most do actually output NMEA but you have to sort connection.

[/ QUOTE ] If its a Raymarine 200 GPS antenna it DOES NOT output NMEA from the 'antenna'. No working bits in that particular mushroom - or at the very least the only first RF stage and buffer amp/first mixer. Appreciate what you say is applicable to some of the more modern ones.

 

[whipper_snapper]

[ QUOTE ]
Yes the GPS Mouse is a good tool - but relies purely on PC being alive and well.

[/ QUOTE ]

Thanks, and I take your point. But in this case i simply want a GPS input to Maxsea and a USB GPS looks like the cheapest and simplest option. I only want it when the laptop is working - if it dies I won't be needing an input to Maxsea. I already have the 'backup GPS' in the 76CSX and an additional dedicated device increases my options. What is more, there is no shortage of stand alone units on board driving DSC VHF and in the grab-bag.