simplest way to get GPS input to a standard horizon

[Poly]

I think I have decided it is time to upgrade to a fixed vhf.

I would like to keep the gps feed separate from my current garmin 76c -for various reasons (cost of cable, sealing cable to console, security, need to mount gps on console etc). I assume it should be possible to get a very basic gps unit (the sort of thing that plugs in a laptop) to connect to the SH radio.

Any comments from those in the know?

Assuming this is possible then Ribnet members would be welcome to quote me for:
SH radio (3500E ?)
Aerial (no A-frame to mount on)
(any other bits I need).

if you want the GPS unit as described above.

It will go to the cheapest deal (inc shipping to scotland) unless someone is willing to wire up the GPS as described...

[jyasaki]

The GPS unit needs to be able to talk NMEA 0183. Assuming that, it's 2 (or 3; don't remember now) wires.

jky

[Jon Brooks]

Polwart

Any real reason why the VM3500?
There will be some cracking deals on both the GX1500 and the GX3000 for the Southampton Boat Show.

Cheers

[codprawn]

Your biggest problem will be powering the GPS unit.

You could use a hand held or in car model that takes a 12v input. My Garmin GPS12 does. You could mount it inside the console - should still pick up signal. Failing that just have the lead coming out and connect the handheld to the lead each time. It always comes in handy as a backup!!!

[4str]

I am no expert, but I have hooked up at least 3 GPS receivers to NMEA devices successfuly, the last one was my Garmin chart plotter to a Standard Horizon radio.

Part of the problem is that GPS technology has advanced further than you need, and it may be hard to find a simple GPS "receiver only" that runs off 12 volts and sends a NMEA signal. I just spent half an hour googling and pretty much came up blank. Most of the interfaces from "receiver only" GPSs are either USB or Bluetooth, and not intended for a marine environment.

Here is one link that may help:
http://planetgps.net/lwr11223.html
This one is NEMA 2000 compliant, Lowarance also makes a similar model that is NEMA 0183 compliant. My guess is (and this is only a guess) that you can cut the plug off the end of the cable leading from the GPS and wire it to 12v power and run 2 more wires to the NEMA input on your radio. I suspect that Garmin and Raymarine etc. offer similar GPS only products, I couldn't find one on Garmin's web site.

The Simplest and least expensive solution would be to buy a mount for your Garmin (if you havn't already), and a serial data/power cable with the bare wires:
https://buy.garmin.com/shop/shop.do?pID=519
Then drill some holes in the console to route the wires so that you can unplug the GPS and the radio when you are not around to watch them.

Hope this helps, l will be interested to hear how you solve your problem.

Steve

[jwalker]

Originally Posted by codprawn

Your biggest problem will be powering the GPS unit. ...You could use a hand held or in car model that takes a 12v input. My Garmin GPS12 does.

I think you'll find that your Garmin GPS12 does not take a 12v input. It does not contain a regulator and should only receive a maximum of 8v. However, that's easily sorted with a wee 7805 regulator and a couple small capacitors.

I do think your idea of a GPS12 is a good one though, since it's a sound unit and the power/data connection is the same as Neil's GPS76c so the connector could be swapped between units if necessary.

Neil, a wee note; the power and data connection pinouts for the GPS76c are wrongly defined in my manual, yours may be wrong too. Here is the correct pinout diagram.

[jyasaki]

Originally Posted by jwalker

I think you'll find that your Garmin GPS12 does not take a 12v input. It does not contain a regulator and should only receive a maximum of 8v. However, that's easily sorted with a wee 7805 regulator and a couple small capacitors.

Hmmm. A quick perusal of the GPS12's manual does show that a cigarette lighter plug adaptor was an accessory. I suspect the 4.5-8V listed in the manual was the input at the battery terminals, rather than the external power input (on the back of the unit.) Either that, or the adaptor had a voltage regulator built into it, in which case your regulator fix would be fine.

Than again, you could also take care of it with an 8V (or slightly less) zener diode and a resistor.

jky

[codprawn]

It is a fairly chunky plug with the Garmin lead so I suspect it may have some circuitry in it as well. Very simple to rig up though if you don't have the lead.

[jwalker]

Originally Posted by jyasaki

...I suspect the 4.5-8V listed in the manual was the input at the battery terminals, rather than the external power input (on the back of the unit.)

Nope.

...or the adaptor had a voltage regulator built into it, in which case your regulator fix would be fine.

Yup.

Than again, you could also take care of it with an 8V (or slightly less) zener diode and a resistor.

Yes, you could but then the available current will be limited by the resistor so to prevent it getting too hot you'll need to start fekkin about. Regulators are made for the job and they cost about 25p...that's about 50cents so why give yourself a problem?

[Poly]

Originally Posted by Jon Brooks

Polwart

Any real reason why the VM3500?
There will be some cracking deals on both the GX1500 and the GX3000 for the Southampton Boat Show.

Cheers

Jon, I think that was stupidity on my part and misreading the advert I was looking at at the time. GX1500 sounds like the one I want - your smallest fixed VHF? ... not likely to be a s/hampton though.

[Poly]

Originally Posted by codprawn

Your biggest problem will be powering the GPS unit.

You could use a hand held or in car model that takes a 12v input. My Garmin GPS12 does. You could mount it inside the console - should still pick up signal. Failing that just have the lead coming out and connect the handheld to the lead each time. It always comes in handy as a backup!!!

I guess in car module inside console was the way I was thinking (no point on paying for cost of displays and buttons etc if all I want is a simple cont. feed.

There is a 12V car accessory socket inside my console.

If I connect my existing h/held (or another h/held) I end up needing a bracket of some sort and probably a custom cable which will be more than a separate in car module.

Console is about 5mm thick polyethylene so expect to get OK signal.

[Poly]

Originally Posted by jwalker

I think you'll find that your Garmin GPS12 does not take a 12v input. It does not contain a regulator and should only receive a maximum of 8v. However, that's easily sorted with a wee 7805 regulator and a couple small capacitors.

I do think your idea of a GPS12 is a good one though, since it's a sound unit and the power/data connection is the same as Neil's GPS76c so the connector could be swapped between units if necessary.

Neil, a wee note; the power and data connection pinouts for the GPS76c are wrongly defined in my manual, yours may be wrong too. Here is the correct pinout diagram.

Jeff, thanks a fountain of knowledge as ever. I can see the benefit in being able to swap 76c and a 12.

[Jon Brooks]

Polwart,

Yes the GX-1500 is the smallest of our line up.
Even though you are not at the show all of our dealers can offer the show pricing.
That pricing is on from now until the end of Sept.

Cheers