NMEA GPS Antenna

[kaman]

Just bought a DSC Standard Horizon fixed vhf.
I want to rig it up so that it I'd GPS enabled.
Apparently I need a NMEA GPS Antenna.
Had a quick look online and some are more expensive than the VHF.
Cheapest I've seen is 60 quid.
Does anyone know of a cheaper effective product.
I use a Hudl tablet in a waterproof case running Marine Maps MX Mariner for coastal navigation.
I don't think there is any means of taking a GPS from the tablet?
Thanks in advance.

[Pikey Dave]

To be fair, I've had experience of the Hudl from family members & up to now they've been rubbish. The point of DSC is that in a "shit or bust" situation, it hopefully calls the cavalry. You wouldn't be wanting to rely on a Hudl in that situation. A bit late now, but the SH GX1700 has built in GPS. If you can get a "proper" marinised GPS antenna for £60 quid, it's a no-brainer (IMHO of course) The other alternative is a handheld Garmin (second hand?) GPS, most of these will output nmea0183 & you have the benefit of a rudimentary navigation aid into the bargain. Even then, the plug for the nmea output on the Garmins isn't usually waterproof.

[kaman]

Thanks again P.D.
I am not at all clued up on this subject.
If i can get a decent Antenna for around 60 quid I'd be happy to pay that for peace of mind.
I'm on a tight budget as major home renovations bleeding me dry!
Waterproof is definitely the way to go.

[ShinyShoe]

Snag with the marinised 'antenna' is its quite big for a SIB?

Alternative option would be a basic "mouse" version with an RS-232 port type connection. Most these days are 5V so you'd need a 12V to 5V convertor (ALA USB power supply) - put all in a waterproof enclosure or even set inside a small amount of epoxy resin? It'll be cheaper (Circuit c£10 on ebay, power c£5), but you wont have anyone to come back to when it fails.. and if it fails at the wrong moment you might have no-means to come back...

[Last Tango]

I use one of the "Evermore" after-market units. Seems to work well and worked straight out of the box.

[jyasaki]

Are you talking about an antenna using NMEA2000 or NMEA0183?

Most NMEA2000 antennae seem to run in the $200 an up range (US dollars.) You will likely need additional stuff to get the NMEA200 backbone operational, so figure that in as well.

You can get some antennae that talk NMEA0183, but they tend to be fairly generic in setup, so you'll have to pick and choose the appropriate accessories to plumb it in to your setup. They are fairly inexpensive (under $50US - google "NMEA 0183 GPS antenna")

IMO, it may be easier to buy an inexpensive chartplotter that will output NMEA0183 and use that instead of a dedicated antenna. Usually 2 or 3 wire connections to get that connected. Plus, you end up with a chartplotter.

jky

[ShinyShoe]

Originally Posted by jyasaki

Are you talking about an antenna using NMEA2000 or NMEA0183?

Most NMEA2000 antennae seem to run in the $200 an up range (US dollars.) You will likely need additional stuff to get the NMEA200 backbone operational, so figure that in as well.

This is for a SIB. He definitely doesn't want to be going NMEA2k.
He just needs an NMEA 0183 feed.

You can get some antennae that talk NMEA0183, but they tend to be fairly generic in setup, so you'll have to pick and choose the appropriate accessories to plumb it in to your setup. They are fairly inexpensive (under $50US - google "NMEA 0183 GPS antenna")

Not seeing any hits in that price range that are the 'traditional' mushroom thing. A GPS mouse would work fine but wont be waterproof. In a RIB thats fine - keep the mouse in the console. In a SIB there is no-where genuinely dry...

IMO, it may be easier to buy an inexpensive chartplotter that will output NMEA0183 and use that instead of a dedicated antenna. Usually 2 or 3 wire connections to get that connected. Plus, you end up with a chartplotter.

Snag is he's got limited power supply IIRC. A plotter will draw maybe 1A/hr a GPS will draw maybe 15mA/h
Wiring connections will be no harder than wiring in a plotter for power and NMEA...

[beamishken]

I think the answer is change the radio for a one with built in gps positioning that way it's all in one box & designed for the purpose

[Pikey Dave]

Originally Posted by ShinyShoe

Snag with the marinised 'antenna' is its quite big for a SIB?

...

No it's not, unless you think 3" is big😎


.....sh1t happens.......

[kaman]

I have a waterproof compartment I could place a non waterproof mouse type GPS in - providing it still works whilst inside?
I like the sound of this idea.
I'm not into changing the VHF unit for one with integrated GPS .
It is for a 3.5m Sib so being compact would be a bonus.

[ShinyShoe]

Originally Posted by Pikey Dave

No it's not, unless you think 3" is big😎

I've heard once or twice its not the size but what you do with it ;-)
You are right 3inch is not big - but where do you put that 3" on a SIB. No A frame, No console, it wants to point to sky...

[ShinyShoe]

So as a suggestion you'd want something like this:

GPS08-15U PS2 Connector Mini size Waterproof GPS Mouse (U-Blox 6 UBX-G6010-ST) | eBay it claims to be waterproof (might not be IPx7 but you know keeping anything 100% dry on a SIB is a challenge so even in a water proof compartment this may be better!) Its more expensive than some others - but some of the others I quickly looked at were wrong baud rate I think. (Not sure which SH Radio you have but I think SH like 4800 baud with GLL, RMB, GGA, GNS sentences.) This one defaults to 4800 and GGA is in its list. GGA contains time of fix, position and some quality info about the fix. All you need!
GLL and GNS are essentially the same info in a different format. RMB has bearings to a waypoint. The mouse doesn't know where you are headed so can't send that info. Not sure the SH radio would display it if it did?

(Most of the explanation is here: NMEA-0183 messages: Overview)

Power with something like this:
Waterproof DC/DC Converter 12V Step down to 5V 3A 15W Power Supply Module | eBay

Quite a few wires in there (I'd whip the PS-2 plug off personally). Then I'd connect from the mouse:

Pin 1 (GND) to Yellow Wire on the power supply AND the NMEA - INPUT on the radio (?green)
Pin 2 (5V) to red next to the Yellow on the power supply
Pin 3, & 5 not connected
Pin 4 may not be needed but if in doubt to NMEA + OUTPUT on the radio (?grey)
Pin 6 to the NMEA + INPUT on the radio (?Brown)

Red and black on the power supply to the 12V battery (red via a fuse +/- switch)

Test... ...will take a few mins for first fix. This unit has a LiIon battery which means it stores the almanac from the sats for up to 7 days. If first fix is after 7 days expect slow first fix, otherwise 30seconds roughly then every second.

I'd use a sticky pad to fix the GPS in place with top surface up. If your compartment is under the seat not sure if the seat will shield signal. adding a person to seat will...

[Pikey Dave]

Originally Posted by ShinyShoe

I've heard once or twice its not the size but what you do with it ;-)

That's just a rumour put about by a bloke with a small.............antenna.
Don't believe what your missus tells you, she's just being kind.

Originally Posted by ShinyShoe

You are right 3inch is not big - but where do you put that 3" on a SIB. No A frame, No console, it wants to point to sky...

The OP has a fixed VHF, I'm assuming he's going to mount it & not just let it flop about in the bottom of the boat. Mounting a GPS puck shouldn't present too much of a challenge, not least because he's also got to mount his VHF antenna somewhere.

[ShinyShoe]

Originally Posted by Pikey Dave

The OP has a fixed VHF, I'm assuming he's going to mount it & not just let it flop about in the bottom of the boat.

Unless I'm mistake he is fixing it under the seat.

Mounting a GPS puck shouldn't present too much of a challenge,

Are we on the same thing? To me a puck is about the size of a standard computer mouse and I agree an easy mount. But I thought you were suggesting a proper marine GPS antenna like this:

That needs to be mushroom up to work, so cant just screw into seat base underneath. anywhere it becomes a handhold! or rope catcher.

not least because he's also got to mount his VHF antenna somewhere.

someone told him size matters so hes got a 5ft floppy one attached to transom!!

[Pikey Dave]

Originally Posted by ShinyShoe

Unless I'm mistake he is fixing it under the seat.

Are we on the same thing? To me a puck is about the size of a standard computer mouse and I agree an easy mount. But I thought you were suggesting a proper marine GPS antenna like this: I am

That needs to be mushroom up to work, I know so cant ("can't" dunno what that means) just screw into seat base underneath. anywhere it becomes a handhold! or rope catcher. Ah I see! It must be impossible then. Probably better just to bodge it

someone told him size matters so hes got a 5ft floppy one attached to transom!! I suppose it would be too difficult to incorporate a mount for the GPS antenna in with the VHF antenna mount.

Maybe an engineer needs to take a look at it

[ShinyShoe]

Originally Posted by Pikey Dave

Maybe an engineer needs to take a look at it

He's on a budget ;-)

[ShinyShoe]

That needs to be mushroom up to work, I know so cant ("can't" dunno what that means) just screw into seat base underneath. It must be impossible then.

I said "can't JUST". I didn't say it was impossible. It was the equivalent of an engineer sucking air. Its an added complication.

I think there is a very different situation for fitting out a SIB to a RIB where you have an A frame and can add lots of appendages if you want to. Just my opinion. Yes you can rig all sorts on the transom and have a whole rig of poles and such like. All with the added complexity of if he wants to ever transport his SIB deflated in a bag needing to be removable etc, while still all robust enough to take whatever the sea can throw at it and whatever someone needing to quickly grab something when getting aboard or a rope when tying up / being towed etc getting caught on it and damaging it. Plus he is using his aux bracket to mount the VHF aerial so another object around the aux may not be what he's after.

Probably better just to bodge it

Is it really a bodge to use a GPS Mouse in a waterproof enclosure? Kaman said he found something for £60. But I'd guess thats prior to any brackets etc. So looking at probably close to £80. With a risk of it being broken by clumsy hands and ropes.

Or <£30 with less risk of it being broken and more compact for use in a SIB?

[kaman]

This is more complex than I first thought lol!
Sib has plenty of waterproof storage to accommodate a GPS mouse style Antenna if placed in a tub.
1 In my sit on Coleman cooler .
2 Inside seat bag.
3 Inside bow box which is covered by a spray hood.

[kaman]

Despite only being a SIB there are several options to mount/locate either mushroom style or mouse type Antenna.
Question is will either work whilst stowed inside a box / container without a clear uninterrupted view of the sky

[Pikey Dave]

Originally Posted by kaman

Despite only being a SIB there are several options to mount/locate either mushroom style or mouse type Antenna.
Question is will either work whilst stowed inside a box / container without a clear uninterrupted view of the sky

Most decent GPS receivers will work inside a non-metallic box. My AIS receiver works perfectly well inside my console. I've no experience of the "budget" end though 😏


.....sh1t happens.......