OpenMarine

I have an old GPS antenna installed on my boat that I have got some readnings from to my VHF, but only when it is supplied with 12 volts. The antenna is a Navman 1220a.

I have tried power the antenna with 5 volts from a USB to serial adapter and get the readings to Raspberry pi and opencpn with no luck. I also tried to supply the antenna with 12 volts and via a voltage divider connect the NMEA out to my USB adapter, but no readnings. 

Are there a way to get my old antenna that seems to need 12 volts to operate to communicate with my Raspberry pi and opencpn or do I have to get a USB GPS?

Regards,

Joakim

Your old GPS does use RS422 communication. You need a RS422 to usb adapter. The doc says it works from 4.5 to 16.5 volts
But the Navman 1220a is old. A new GPS is better (less energy, faster, more accurate).

Martin