Sea Talk GPS replacement

dulcibella

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The GPS antenna/receiver unit on my 1996 vintage Raytheon/Autohelm Sea Talk system has failed (dome cracked and water ingress). Any suggestions on a currently available and compatible unit would be gratefully received!
 
If you want to stay with seatalk it has to be Raymarine. Unfortunatly their gps antennas are expensive and don't have a great gps " engine".
Most Raymarine chartplotters will accept a NMEA input which widens the choice considerably.
Personally I prefer a gps unit with a small B &W screen. It will then work independedenty from the chartplotter. Good for redundancy and if you want low power like for an anchor watch.
The Furuno GP 32 is a good option or even one of the Garman handheld units permantly wired to 12v.
If you just want an active aerial without any display there are cheap units available on eBay.
 
Really need to know a bit more. Is the Raymarine GPS unit an all in one where it outputs Seatalk (you can tell because there will be 3 or 4 wires in the wire coming off it) or is it a Raymarine GPS where a co-axial cable is coming out of it?
i.e. as fitted to a Raytheon 300/320.
 
If you want to stay with seatalk it has to be Raymarine.

The early "autohelm" "black box" GPS unit which I have, and also I believe the following "raytheon" unit actually only put out nmea 0183, relying on something else to translate to seatalk: either a navdata unit or in my case an st50 navcenter. Assuming that part is intact, nmea version incompatibilities aside (I'm guessing a simple GPS should be ok but stand to be corrected by those more knowledgeable) a unit outputting nmea 0183 might be fine.

Dulcibela: Do you know which unit you have, what it's connected to and/or what it outputs?
The manuals are here if help is needed in identification
 
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The early "autohelm" "black box" GPS unit which I have, and also I believe the following "raytheon" unit actually only put out nmea 0183, relying on something else to translate to seatalk: either a navdata unit or in my case an st50 navcenter. Assuming that part is intact, nmea version incompatibilities aside (I'm guessing a simple GPS should be ok but stand to be corrected by those more knowledgeable) a unit outputting nmea 0183 might be fine.

Dulcibela: Do you know which unit you have, what it's connected to and/or what it outputs?

It should say on the label on the top of the mushroom head if it is still readable but agree with laika some people fitted NMEA units, others Seatalk..
 
If it isn't a mushroom but a fat slightly tapering aerial ~25-30cm long with a run of coax to a flat metal box with "autohelm" written on it, it's the one I've got
 
Type of unit

It's an all-in-one unit called the "SeaTalk GPS transducer" - just says GPS on the dome but manual describes it as having a built-in SeaTalk interface. The wiring diagram shows it as having 3 wires (yellow, black and red) in the cable, which connect into the SeaTalk system through a simple junction box. Data output is "NMEA 0183 sentences to SeaTalk interface". The other instruments in the system are ST50 and a ST4000 autohelm (which won't work at all without the GPS input).
 
Personally I prefer a gps unit with a small B &W screen. It will then work independedenty from the chartplotter. Good for redundancy and if you want low power like for an anchor watch.

Me too - most of the time I just want something that will display lat&long and pump it into an NMEA bus, and let me create the occasional waypoint and show range and bearing to it. The classic Garmin GPS128 is ideal. Sadly, there isn't really a modern counterpart - either you go for a black-box GPS with no display or controls, or a full chartplotter it seems.

The Foruno you mentioned looks good, though a bit large, but the RRP is over $500, which probably translates to £500 on the shelves in this country, and that's just too much for a simple GPS.

Pete
 
It's an all-in-one unit called the "SeaTalk GPS transducer" - just says GPS on the dome but manual describes it as having a built-in SeaTalk interface. The wiring diagram shows it as having 3 wires (yellow, black and red) in the cable, which connect into the SeaTalk system through a simple junction box. Data output is "NMEA 0183 sentences to SeaTalk interface". The other instruments in the system are ST50 and a ST4000 autohelm (which won't work at all without the GPS input).

You should be able to replace that with one of the gps sensors available off Ebay for not a lot of money. There should be no real trouble wiring it in, three cables being the norm, +ve, -ve and NMEA.
 
If you are really stuck and have to have a Seatalk one I'll do a YAPP and make you one. Serial GPS tansducers can be got for about £25 (Globalsat BR-355 being an example) and they work inside the cabin on a GRP boat. The NMEA to Seatalk bit will just be a rehash of previous YAPPs.

SAMYL is being misleading with his post. If you can only connect a Seatalk transducer to the rest of your system a NMEA one will be no good.
 
If you are really stuck and have to have a Seatalk one I'll do a YAPP and make you one. Serial GPS tansducers can be got for about £25 (Globalsat BR-355 being an example) and they work inside the cabin on a GRP boat. The NMEA to Seatalk bit will just be a rehash of previous YAPPs.

SAMYL is being misleading with his post. If you can only connect a Seatalk transducer to the rest of your system a NMEA one will be no good.

I was suggesting replacing the gps bit not the transducer.
 
The other instruments in the system are ST50 and a ST4000 autohelm (which won't work at all without the GPS input).

The ST4000 will take an nmea 0183 GPS input according to the manual.

If for any reason this is not what you want, Angus's suggestion sounds considerably more cost effective than than the "new" raymarine options of the E85001 nmea/seatalk converter or Raystar 125+
 
I was suggesting replacing the gps bit not the transducer.

The GPS bit is the transducer.

I still don't understand what you are suggesting. The OP has a Seatalk GPS transducer. You are suggesting replacing it with a NMEA one. If the rest of his system does not have a NMEA input capability, a NMEA GPS transducer will not be any good without a NMEA to Seatalk converter, which can be bought for big £, or made for less.
 
As Laika says the ST4000 will take an ordinary gps with nmea output into it. I have done that to mine.
So you can buy one off ebay for not very much and just wire it in as I suggested above and it will work perfectly well without going down the megabucks route of buying raymarine again.
 
My Raystar 120 packed up recently and after much searching and assistance from forum and raymarine replaced with a new raystar 130 with network conversion kit to 'downgrade' to seatalk 1 system. Lost some detail on seatalk systems and cant see sats any more on chartplotters but very accurate and fast to aquire sats. Wasnt cheapest option but will allow me to upgrade instruments via Seatalk ng in future.
If you can pick a 125 plus up if you can source one??? this provides a network conversion kit and cables in the box. Or use a generic GPS.
 
Serial GPS tansducers can be got for about £25 (Globalsat BR-355 being an example) and they work inside the cabin on a GRP boat.

This will be a basic question for the cognoscenti but a couple of days googling buck converters and looking at the stwitched mode wares of farnell and RS gives me too much info so I need to ask...

What's the most appropriate way to step down from 12v (boat batteries) to 5v, smoothing out any transient drops when the fridge turns on etc. in order to power a device like the one mentioned above? I'm hoping for something which will cost rather less than what it would be powering (and I don't have a spare 12v phone charger kicking about to hack)
 
This will be a basic question for the cognoscenti but a couple of days googling buck converters and looking at the stwitched mode wares of farnell and RS gives me too much info so I need to ask...

What's the most appropriate way to step down from 12v (boat batteries) to 5v, smoothing out any transient drops when the fridge turns on etc. in order to power a device like the one mentioned above? I'm hoping for something which will cost rather less than what it would be powering (and I don't have a spare 12v phone charger kicking about to hack)

I've used one of these..
http://uk.rs-online.com/web/p/linear-regulator/5164799/

You'll need a heatsink, but cheap as chips..
 
Problem solved - thanks everyone!

I managed to get a Raystar 125+ from Mailspeed Marine for a sensible price - it was delivered the following day, too. A conversion kit was included in the box but this wasn't needed as the Seatalk 1 output from the 125 feeds directly into my system - just disconnected the old cable and connected the new.
Thanks to all for most helpful and interesting suggestions.
 
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