Connecting GPS to VHF

Gumpy

Well-known member
Joined
12 Dec 2006
Messages
1,577
Location
A far corner of Little England
Visit site
Now because I like to fiddle I never seem to get things done the easy way!
I have a Cobra VHF and a GPS mouse which it says ouputs NMEA down the USB cable to the PC.
So I duly made a splittter box and added the VHF set to the two lines that transmit data to the PC.
Simple I thought one TX two RX on the NMEA line, except as soon as I add the splitter and the VHF set the GPS stops working.
Apart from purchasing a dedicated GPS for the VHF set does anyone have any ideas?

Julian
 

CPD

Well-known member
Joined
20 Sep 2006
Messages
3,010
Location
Hampshire
Visit site
I have a Garmin etrex plugged into a cobra and it works very well. I would guess that the mouse needs power to operate which it takes from the USB socket. Maybe if you haven't powered the nmea (normally taken from USB), then it wont work ?? I may be completely wrong.
 

Danny

New member
Joined
23 Oct 2003
Messages
955
Location
Me: St Albans. Boat: Portsmouth
www.compasscard.co.uk
As Raquet has already said it's a different interface. Unfortunately a Serial/USB converter is unlikely to work in this situation as it would probably require power from the USB port - which it won't get from the GPS mouse (the power comes from the PC's USB port).

Does your PC have a serial port? (9 pin D connector. Usually male). If so, then you could use a program such as Franson GpsGate to replicate the GPS mouse to the serial port, which you could then connect to the VHF.
A drawback to consider with this setup would be that the PC would need to be running at all times!
 

Gumpy

Well-known member
Joined
12 Dec 2006
Messages
1,577
Location
A far corner of Little England
Visit site
Good thought!
I had been looking at that software but didnt think of replicating it through the serial port.
Doesnt matter that the PC has to be on as thats my GPS/navigation system
Goes off to investigate more!



J
 

pappaecho

New member
Joined
13 Oct 2004
Messages
1,841
Location
S. Hampshire
Visit site
Actually nmea is more like current loop than rs232. You may have success if you understand that send and receive need a baseline connection which is usually the -ve. In addition you will have to decide whether it is send and receive or receive only ( only connects in software either Tx and Rx or rx only)
Finally you may need to tinker with the baud rate
 

Danny

New member
Joined
23 Oct 2003
Messages
955
Location
Me: St Albans. Boat: Portsmouth
www.compasscard.co.uk
If you did want to use GpsGate here's how it could be done.

If your GPS USB mouse has a driver with it that creates a virtual com port - and most do as a lot of GPS enabled software only supports com ports (including mine) - then you would set up GpsGate to use this com port as input.

You would then define two GpsGate outputs: one would be the PC's real com port and the other would be a virtual com port that your existing PC charting software would use.

You would connect the 'Transmit Data' pin and the 'Signal Ground' pin on the PC's com port (using a 9 pin female D connector) to the appropriate NMEA input connections on the VHF.

If you wanted to run another GPS software program simultaneously on the PC then just define another virtual com port as output in GpsGate.

Each PC program needs to be configured to use the virtual com port you've decided to allocate to it (to the program(s) these look just like real com ports with GPS receivers running on them).
 

Gumpy

Well-known member
Joined
12 Dec 2006
Messages
1,577
Location
A far corner of Little England
Visit site
Thanks for that, I will be going down that route, just seems so obvious really.
It will also enable me to run other software that uses the GPS on the pc at the same time.

Just have to make sure I get all my testing done in the 12 days and am happy with it working before I buy..


Julian
 

RestlessL

Member
Joined
6 Apr 2007
Messages
703
Location
Solent
Visit site
I have connected a serial gps mouse to the VHF with some success.

Serial units are not common now, but can still be found. Mine was the Haicom Hi-204 receiver, which is normally sold for use with PDAs. If you go down this route, remember that the GPS mouse only needs 5V, and may blow if you give it 12.
 
Top