GPS communication to VHF radio

[mpoulter]

I use a GPS that plugs by a USB port into my nav station computer.
I need to buy a new VHF radio which will have DSC capability. Has anyone out there managed to connect the GPS information to the Radio?

Thanks

[btrayfors]

Yes, very simple. Two wires if you want to get GPS info to the radio via NMEA0183 protocol. Three wires if for some reason you want the radio to transmit back along the NMEA connection.

Buy a brand name VHF...Icom or Standard are good. You should have no problem hooking it up after you read the instruction booklet.

Bill

[mpoulter]

Hi thanks for the reply but I am not clear.
Two wires from where? The GPS is a sealed disk with single cable ending with a male USB plug (that goes into the computer).
The trick is either spliting the signal or getting it off the computer.

Thansk for your patience

mp

[btrayfors]

mp,

Probably off your computer's serial port (assuming it has one) and if you're using a charting program on the computer as I assume you are (why else go to the computer?).

Bill

[hellosailor]

mp, I think you will either need two GPSes, or one rather more expensive one.

The problem is that NMEA serial connectors are not the same as USB "Universal" serial bus, they are both "serial" in the same sense that Mother Teresa and Britney Spears are both "females".

To use a USB device like a USB GPS, it has to be plugged into a USB "host" device, which normally means a full-blown computer. (That's slowly changing, but not yet, not this or next year.) If your computer only has a USB bus, no RS-232 serial connector, you are best off just using a USB GPS with it.

If your VHF requires a serial cable (a DB-9 nine pin computer type?) it needs a standard serial output from a GPS. Some of the more expensive GPSes offer both outputs from one unit--but you'll probably find it is cheaper to buy another GPS to use with the VHF, and leave the "hockey puck" style GPS with the computer.

The extra redundancy isn't a bad thing on a boat, the units have gotten so cheap it won't hurt badly.

[Captain Bill]

The issue is that most modern computers don't have serial ports so you have to buy a serial to USB adaptor. Then you need a NMEA 0183 to PC adapter. You might be able to find one unit that does both. You will then need some software that will output the GPS "NMEA 0183 position sentences" to the port. I haven't tried this specific configuration but Coastal Explorer can put it's data on the bus as a "talker" or repeat data from other devices as a "repeater". In any case you can't hook a USB hockey puck GPS directly to the radio. The computer will have to go between the GPS and the radio. Your other option is to just bite the bullet and spend the money on a GPS with an NMEA 0183 output. By the time you cobble together the other solution and spend all the time troubleshooting it, it will probably cost you more money. The other advantage is that you'll now have two GPS's on board in case you loose one.

[btrayfors]

Some chartplotter programs for PCs allow you to "Pass Thru" GPS info to other devices, e.g., autopilot or VHF. Offshore Navigator, which I use, has such a capability. You get to define the GPS input port (USB in this case) and export port (e.g., Com1, Com2, etc.). You also get to choose the NMEA sentence format.

In theory, at least, this should allow a GPS position, derived from a USB-connected GPS, to pass the data along to the VHF or autopilot via a serial port, if the laptop has one, or a USB to serial port adapter if it doesn't.

Bill

[Ziggy]

The simplest way to do it is with a USB-to-NMEA0183 gateway, like the Actisense USG-1: Introduction

Of course the gateway may be almost as expensive as a second GPS with NMEA 0183 output

[richardhula]

As several posts above mention, you need to get the GPS data being fed into your PC out again to your DSC VHF radio.

Physically this will require a COM port to output the data. If your machine is a laptop made in the last five years & therefore doesn't have one, you can use a USB-COM port adaptor. If it's a PC you could use a COM port card as an alternative. Either way you will have a d-sub 9 pin connector to supply your GPS feed.

Software wise you need some means of distributing the GPS data. It's possible that a chartplotter application you use may have an echo facility to re-route the GPS data to your COM port, otherwise Franson GpsGate is a neat & low priced application that will do just that & a lot more. Once configured it can run as an auto-start service in the background.

Typically the GPS feed would be input to GpsGate & almost any number of outputs could then be set up. One would be to the COM port that would connect to your radio, other (virtual) COM ports could feed applications within your machine (chartplotter, position reporting software etc.)

On ICOM VHF radio's the NMEA in(GPS) & NMEA out(DSC messages) are usually on RCA female connectors, so you could just connect from pin 3(NMEA+) & pin 5(NMEA-) on the d-sub COM port plug with screened lead to an RCA plug (NMEA+ to centre pin) connecting to "NMEA in" on the radio.

Regards

[bitman]

that why i don't understand why those vhf radio's don't have a simple usb connector on the back so you can connect a usb gps mouse...

now most of the times (in our boat the gps is coming from the raymarine a65 chart plotter) it's coming from the main gps system.

nice if you have a real problem and need to call mayday while your gps system is broken this underminds totally the use of the dsc system!

i much better (redundant) system could be a vhf radio with a usb connection where you could connect a cheap usb gps mouse. stick it some where and as long as you have some kind of power to keep your dsc vhf is running your fine!

to many times i see no or little redundancy on yachts, may be this is because of my job...

[Wanderlust]

For those that have suggested how to connect through a PC, to me this is not very logical. It may work but not be a viable solution.

The first issue is having to boot the PC to pass the info to the radio, otherwise no DSC.

The second issue is the ongoing power consumption of the PC.

The third issue is that PCs don't do terribly well in emergency situations - the most likely time when you really need DSC.

To me, the only reasonable solution is a GPS that is compatible with the radio. You then have redundancy as well.

[Tropic Cat]

Originally Posted by mpoulter

I use a GPS that plugs by a USB port into my nav station computer.
I need to buy a new VHF radio which will have DSC capability. Has anyone out there managed to connect the GPS information to the Radio?

Thanks

I haven't done mine yet, but I after reading the manual on my Standard Horizon VHF I don't consider the interface to be a problem . As has been mentioned, I don't believe outputing data from a PC is viable for the reasons stated. The answer is to obtain another GPS.

They sell the cheap "brick types" here with NMEA output for less than $40.00.

Wire it directly into the radio with an inline power switch and the problem is solved.

[Heikki]

The previous posts have more than well covered the issue of the GPS signal itself. This is just a side note: when you are connecting your second GPS to your radio, you have to use the original cigarette lighter plug - assuming that is the original setup. It is not just a big and ugly plug, it also converts the voltage from 12V to 5.3V (or something around there). Wiring 12V in directly will burn you GPS-chip for sure. Trust me. I have done that.
If this was not a public forum, I would tell you that I have done it even twice in two boats in two consecutive years. But as this is a public forum, I do not dear to embarrass myself and let everyone know how slowly I learn… if ever…

[richardhula]

Originally Posted by bitman

that why i don't understand why those vhf radio's don't have a simple usb connector on the back so you can connect a usb gps mouse...

That's a long way off I think. At the moment the best you can hope for are manufacturers abiding by a common protocol, in this case NMEA.

Originally Posted by Tropic Cat

As has been mentioned, I don't believe outputing data from a PC is viable for the reasons stated. The answer is to obtain another GPS.

I agree, I was just answering mpoulter's request.

Nobody has mentioned the other option of having say a self contained GPS mushroom outputting NMEA to a central distribution block. You can then connect several devices to this point distributing GPS position as required.

I have VHF & SSB DSC radio's, a Yeoman chartplotter & a multiplexer attached to a Garmin GPS 17HVS. Redundancy via a handheld Garmin GPS 48 with NMEA output lead if required, although the AIS transponder also has built in GPS. The flying jack is used for programming & firmware upgrades of GPS17.

[hellosailor]

"that why i don't understand why those vhf radio's don't have a simple usb connector on the back so you can connect a usb gps mouse..."
Again, YOU CAN DO THAT. But without an intelligent USB "host" device, aka a full-blown computer, all you can do is "plug it in". Nothing will work, but you can "plug it in".
USB devices will not work unless they are connected to host computers. There are new chipsets that they will work with--but these are still new, expensive, and exotic, you won't find them in much of anything for a couple more years. They still require "brains" to make them work, and even if "computers" are now to be found in $50 cell phones and other devices--that's a huge extra expense for a radio, compared to not using any "brains" and just plugging in a serial output GPS.

You can stick a chicken in a pot, that doesn't mean it will become chicken soup.

All the complicated solutions are exactly that--way overcomplicated, way over expensive, the cheapest and simplest solution here is BUY A SERIAL GPS for $40-50 and plug it into the VHF. No screwing around needed. And if you have to punch the distress button--you don't have to worry about the computer working, either.