Connecting a GPS device to my VHF

Tim R. · Apr 12, 2012

Re: Connecting a GPS device to my VHS

You probably need a puck style antenna with NMEA 0183 output to connect directly to your radio. You will also have to provide power to the antenna. Try to find one that has a power sense wire so turning on the radio will also activate the antenna.

Check your radio manual to verify it accepts NMEA 0183.

The Garmin GPS 17x HVS should work. There are probably cheaper units that will also work. One nice thing about the Garmin is that it will work below decks.

kenn · Apr 12, 2012

knothead said:
We have a Standard Horizon GX 1500E VHF radio onboard. We would like to connect a GPS device to the radio to enable it's location functions. Our GPS capability is presently via laptop/SeaClear with a Magellan handheld as a backup. The laptop receives its signal from a USB-powered puck antenna.

Tim R is correct.

Just about all USB-GPS receivers ("pucks" or otherwise) consist of a GPS subsystem that puts out the NMEA 0183 GPS stream, and a serial-to-USB interface to convert it. It would be remotely possible to hack these cheap interfaces to get at the NMEA signal, but not worth the hassle.

How old is the Magellan unit? If it's not ancient, it might be suitable as a feed to the VHF, and you might be able to come up with either powering or charging the Magellan from house 12v. It would be worth a try.

Otherwise... the aforementioned Garmin GPS 17x HVS or similar is the simplest option.

Maine Sail · Apr 12, 2012

knothead said:
Connecting a GPS device to my VHS

Have you considered connecting it to a BlueRay or DVD instead? VHS is so yesterday....

I fixed your title for you...

Scott B · Apr 12, 2012

Maine Sail said:
Have you considered connecting it to a BlueRay or DVD instead? VHS is so yesterday....

I fixed your title for you...

But Beta was much better........

c_witch · Apr 12, 2012

knothead said:
We have a Standard Horizon GX 1500E VHF radio onboard. We would like to connect a GPS device to the radio to enable it's location functions. Our GPS capability is presently via laptop/SeaClear with a Magellan handheld as a backup. The laptop receives its signal from a USB-powered puck antenna. I've looked at the radio's manual and searched various websites about GPS antennae but I've come to the conclusion that I don't have either the experience or the intelligence to figure out what to buy. What will make the Standard Horizon locator system work short of buying a completely new GPS unit (my free one works fine) or cabling the Magellan to the radio somehow and hoping that I have enough AA batteries aboard to keep it running constantly?

Hi,

I'm in the same predicament as you except that I am running Linux on my laptop and OpenCPN navagation software. There are multiplexers on the market to split the signal from the antenna to both devices but they are a bit costly. I am hoping to get the author of OpenCPN to add a module to that program that will communicate with the vfh via a second usb port. I've been told that it is possible to write a program to communicate with the gps driver and do the same thing but I think its beyond my progamming abilities at this time. Try searching for mulitplexers and you may find something, if you do let me know.

c_witch

SeaTR · Apr 13, 2012

What does that little green face mean? ...

"big grin"...

Scott B · Apr 13, 2012

knothead said:
Thanks. I actually meant to say "8-track tape". Maybe that's why I can't get the radio to work when I try and play my Lawrence Welk Greatest Hits album. I wish you could have also fixed the fact that I said almost the same thing twice, but at some point I guess I've got to change my own diapers. The good news about senility is that one no longer has to cover up the fact that one isn't half as smart as one pretends to be. What does that little green face mean?

I saw you had started two threads that were very similar but different so merged them together rather than deleting one. You can or we can delete or edit them.

Bill Roosa · Apr 13, 2012

good morning folks
the USB puck type GPS does indeed output NMEA serial data streams.
the issue is not of converting the data but of both powering the puck and converting the usb to a serial set of two wires. The USB to serial is a piece of cake and just neuter the USB end of the puck and you have it. The power has to come from some other source as the VHF does not do power on its nmea circuit. Course the radio has a power connection on the back that you could tap into but you are looking for 5 volts not 12 so that is the real rub.

http://pinouts.ru/Devices/mini-USB_pinout.shtml
for all your pinout and cabling needs. If you go up one level (devices) there is a section for GPSes with USB but you did not mention the name of your puck. The diagram is for a mini-usb but the cable wiring is the same.

The other method is to take the nmea stream from the computer and run it out the serial port. Then run wires to the VHF....... Assuming you are running winders this is not at all easy as they really don’t want you messing around with the secret inner workings of the OS. With Linux it is a snap as there is already a daemon running for the USB which just needs to be told to also report to the serial port. Course you still have to run the wires but you were going to have to do that anyway.

If you don’t mind voiding the warranty on the VHF you can crack the case and find a 5 volt source in there somewhere.......easy cheesy lemon squeezy.

kenn · Apr 13, 2012

Bill Roosa said:
good morning folks
the USB puck type GPS does indeed output NMEA serial data streams.
the issue is not of converting the data but of both powering the puck and converting the usb to a serial set of two wires. The USB to serial is a piece of cake and just neuter the USB end of the puck and you have it. The power has to come from some other source as the VHF does not do power on its nmea circuit. Course the radio has a power connection on the back that you could tap into but you are looking for 5 volts not 12 so that is the real rub.

http://pinouts.ru/Devices/mini-USB_pinout.shtml
for all your pinout and cabling needs. If you go up one level (devices) there is a section for GPSes with USB but you did not mention the name of your puck. The diagram is for a mini-usb but the cable wiring is the same.

Sorry to contradict, but I can't see how this could work. USB is not simply old-school serial in a different connecter. (I'd love to be proved wrong...)

Bill Roosa said:
The other method is to take the nmea stream from the computer and run it out the serial port. Then run wires to the VHF

Yes this is a possibility, but most modern laptops don't have serial IO ports. Also, in an emergency, when you most need valid GPS data at the VHF, does it make sense to rely on a kludge involving a laptop and a cheap GPS puck (neither marinized), a slew of adaptors, and -gasp- Windows?

c_witch · Apr 13, 2012

"
Yes this is a possibility, but most modern laptops don't have serial IO ports. Also, in an emergency, when you most need valid GPS data at the VHF, does it make sense to rely on a kludge involving a laptop and a cheap GPS puck (neither marinized), a slew of adaptors, and -gasp- Windows?

"

I don't see the difference between this and and plugging/wiring the vhf into a chartplotter with an internal antenna or external one, seems like the same difference to me.

c_witch

PS although I do agree about 'Windozzzzz'

kenn · Apr 13, 2012

c_witch said:
I don't see the difference between [getting GPS data out of a laptop with a GPS puck] and and plugging/wiring the vhf into a chartplotter [or other marine GPS instrument] with an internal antenna or external one, seems like the same difference to me.

The difference is that in the latter you're connecting (usually) securely-mounted, 12v-powered "marine" -grade devices together, using NMEA 0183 ports that were designed and intended to be used together, vs what would end up a hodge-podge of laptop, laptop power adaptor, USB to serial interface, (cos laptops don't have NMEA-ready serial out), and a hand-rolled cable or adaptor to NMEA 0183. What happens when the boat rolls and your laptop falls off of your nav table? If you move your laptop around, will you make all the connections correctly every time? Will you remember to start the laptop every time with the correct drivers and software?

(Electronics is one of my fields and I've got a $30 GPS fob working nicely on an ASUS netbook running OpenCPN on Ubuntu. Works cool! But I'm not gonna pretend that this is a dependable GPS source for a DSC radio)

c_witch · Apr 14, 2012

kenn said:
The difference is that in the latter you're connecting (usually) securely-mounted, 12v-powered "marine" -grade devices together, using NMEA 0183 ports that were designed and intended to be used together, vs what would end up a hodge-podge of laptop, laptop power adaptor, USB to serial interface, (cos laptops don't have NMEA-ready serial out), and a hand-rolled cable or adaptor to NMEA 0183. What happens when the boat rolls and your laptop falls off of your nav table? If you move your laptop around, will you make all the connections correctly every time? Will you remember to start the laptop every time with the correct drivers and software?

(Electronics is one of my fields and I've got a $30 GPS fob working nicely on an ASUS netbook running OpenCPN on Ubuntu. Works cool! But I'm not gonna pretend that this is a dependable GPS source for a DSC radio)

I still really don't follow your reasoning. Your ok to use the laptop gps data for navigation but find it unworthy for the dsc function on a radio???

Lets get away from all the hype about the actual plug in connections too. NMEA 0183 breaks down to being ASCII formated sentences beginning with a '$' and terminating with a 'CR' and 'LF' and using comma's as delimeters in the sentence.
The usb gps antenna sends the sentences via usb connection to the laptop where a 'driver' simply stores the incoming message to a buffer. Programs are then notified that new data is available and they may then request it or ignore it etc. All we are after is a way for the vhf to be included in this loop via usb cabling (as most modern laptops no longer have serial ports).

My radio is a simple Standard Horizon Eclipse and all it is interested in is the Time,Latitude,Longitude,Speed over Ground and Course over Ground.

Years ago my first computer was a Sanyo 555. I could not find any communications programs to work with it as the hardware was NOT IBM compatable, so I ended up writting my own program to deal with incoming data from the comm port, which eventually turned into a full blown communications program. I might also add that I didn't even have a compiler for higher level languages at the time so ended up writting it in assembly using 'Debug'.

c_witch
<Edit additional information>
I do agree that no one should simply leave a laptop sitting loose at the nav station. Mine is securely fastened to its own drop down table. I also intend to use a proprietary cable allowing me to plug it into the accessory port (cigarette lighter) rather then use the 110v adapter.

Another thing to consider about a laptop. If for some reason one were to experience a catastrophic power failure then all 12 volt systems will go down. With a lap top it will switch to its internal battery which will afford at least 2 if not more hours of available gps funtionality.

kenn · Apr 14, 2012

you're missing my point. The time you would most benefit from having a valid GPS feed to your VHF is when the sh!t has fit the fan - boat in danger, man overboard, illness/injury. That's not the time to have to be saying "did I boot the laptop? Is it connected? Is my homemade adaptor working? etc"

Your example of using a laptop as chartplotter is different in that you're using this in good conditions, and you have all manner of fallbacks, including compass and dead reckoning. And again, if you were in a critical situation (eg fog or visibility-reducing storm), a custom, haywired system doesn't seem to be the right choice.

Sure, this board is populated with clever folks. Many of us could probably whip up a halfway reliable laptop-based system. But they would still be inferior to a properly-engineered system, in terms of reliability and operational simplicity.

[my turn for an edit] I do think boat electronic systems will evolve into something based on a core "processor" that the sensors and displays all plug into, using NMEA2000, CANBus or similar buss as already used in industry and the military. This core processor itself will be industrial or automotive grade, not a laptop from BestBuy, running a dedicated self-booting operating system, and firmly mounted. Waiting for a NMEA2000 -enabled blender so I can remotely make margaritas.

[/edit ]

Stu Jackson · Apr 14, 2012

Good points, kenn.

The "logical" device would be a VHF with a built-in GPS, and just be done with it.

Too simple, huh? I think one manufacturer makes one now, but the obvious reason they don't is they can sell a separate radio and a separate GPS and have us all read all sorts of messages on these boards: "How do I hook them up?" Can't begin to tell you how many hundreds of these I've seen.

kenn · Apr 14, 2012

c_witch said:
There are multiplexers on the market to split the signal from the antenna to both devices but they are a bit costly. ... I've been told that it is possible to write a program to communicate with the gps driver and do the same thing but I think its beyond my progamming abilities at this time.

Sorry, I didn't see this earlier.

From studying the cheap $30 USB-GPS fob I've currently got, and from research, I've found that these fobs or pucks have two major components; a GPS chip that receives the satellites and puts out continuous NMEA-compatible serial GPS data strings, and a serial-to-USB adaptor chip. (to the computer, the GPS-USB puck appears as a basic serial-USB adaptor... which it is. It shows up as a comm port) As I hinted earlier, if your hacking skills are advanced and include surface-mount soldering, it would be possible to access the NMEA stream from the first chip. You'd have to add a port driver IC to protect the GPS chip.

I also have some stand-alone serial-to-USB adaptors ($7 for two of them off of ebay

), using the industry-standard DB9 serial connector and they use the exact same adaptor chip as my GPS fob above. I've successfully taken the NMEA0183 output from a Garmin etrek Vista (handheld GPS) and run it into my netbook using one of my serial-to-USB adaptors. So this suggests another route - buy a marine-grade GPS module like the Garmin mushroom discussed earlier and connect its NMEA 0183 output to both your DSC VHF receiver and a serial-to-USB adaptor. I believe a simple parallell connection here would not degrade the signal, but I haven't verified this.

The cheaper GPS modules are talk-only; there's no bidirectional communication, they look for satellites as soon as they power up, and just fart out GPS info nonstop once satellites are acquired. So I don't think a full multiplexor is necessary.

Hope this helps.

fdr14127 · Apr 23, 2012

Doesn't appear that anyone posting here knows about the gps driver. Google 'gpsd' and you will find that it will talk to most linux based nav programs. I use it with opencpn, polarnavy and seaclear running under wine on linux. It will take inputs thru the usb port and serve them out. Having said that I use a dedicated Garmin $180.. unit designed for the delivery trucks to interface my ICOM receiver for the dsc function and therefore don't need to boot up the laptop for day sailing.
You will probably need to compile gpsd as it has a new release and the distributed linux systems are out of date. The advantage is that the newer versions will drive the nav programs with AIS data as well. I am in the process of updating the output of the nav programs to the TackTic NEMA interface and will have it all displayed on the cockpit instruments. Oh and try to keep Crazy Otto the auto pilot on course as well.

Somebody ought to get the distributions to update their binaries to gpsd 3.5....summer of code project for some college freshman?