usb gps to vhf

hi folks, just got a navman 7100 vhf. my gps is a usb mouse type connected to my laptop which is running maptech chart navigator, and hopefully shortly, my raymarine auto pilot , would it be possible to put a usb lead on the vhf to transmit my position. HELP , buggsy

just to be clear you want to connect:

USB GPS mouse --> Laptop --> Ramarine autopilot
. . . . . . . . . . . . . . . . |
. . . . . . . . . . . . . . . . +-----> Navman VHF

If the laptop has a spare RS232 (serial) port on it, then it may be possible to feed the USB position out on RS232 (using NMEA standard) and into the Navman. If there is no serial port then you would need a USB-serial convertor and again in theory it would be possible, BUT (and its a big but) theoretically possible and simple are not necessarily the same thing.

I suspect that unless you are proficient with computer interfaces (USB, RS232 etc) then you would be much simpler and potentially just as cheap to buy a cheap GPS with serial/NMEA out, and connect this to the navman.

Would be much simpler and potentially just as cheap to buy a cheap GPS with serial/NMEA out, and connect this to the navman. You would also not be depending on the laptop functioning to provide position to the VHF.

BTW, how are you connecting the Autopilot to the laptop?

USB has a nasty habit of losing connection sometimes - just what you don't want!!!

If your laptop is a half tidy one you should have a pcmcia or pc card slot. You can buy these with RS232/serial connectors.

You can also buy a usb/serial lead which would plug into the laptop and then you could connect the VHF to it BUT how good it would be I haven't a clue - it's one of those try it and see situations.

I would be tempted to buy a cheap Garmin hand held - it's always handy to have a backup GPS anyway!!!

The laptop will need some form of software on it that will take in the position data from the USB GPS and push it out on an RS232 port - you can't convert from USB data to RS232 serial data without some form of intelligence between the two - RS232 to USB is easy by comparison.

There may be software out there to do it, but as others have already said it is not the easiest / most reliable approach, considering that the position into the VHF radio is a safety benefit, and autopilots are definitely best kept as far away from Bill G's empire as possible.

You also need to check that the Navman 7100 accepts RS232 data - many VHF are looking for RS422 or RS485 data (a different hardware format for serial data transmission.

Cheers

Chris