I have recently installed an AIS
transponder that has the ability to output NMEA
data. It also has a USB cable which I am using to see AIS
targets on my charting software
(OpenCPN) and also to provide GPS
data to the laptop
. This much is working perfectly.
I also have one of these: Raymarine Marine Electronics - PC-SeaTalk-NMEA Interface Box
and am trying to get the GPS
data from my AIS unit out to my Raymarine
instruments over seatalk
I think there is a problem with the nmea
converter as when everything is powered up i get a green light on the converter for Seatalk but no light for NMEA. I have double checked that the AIS unit's nmea tx wires are connected to the converter's NMEA in and the rx wires are connected to NMEA out. I have even tried reversing this to no avail. My AIS unit is set to transmit NMEA data at 4800 baud which should be what the seatalk converter is looking for. I am not trying to get AIS data to the instruments just GPS data so this 4800 baud should be right. I have used a digital multimeter on the NMEA connections and am seeing zero volts on the NMEA out at the seatalk converter. I am seeing about 3.25 volts on the NMEA in wires but the polarity seems reversed as when I connect my negative meter lead to the NMEA tx (-) wire and my positive meter lead to the NMEA (+) wire I see -3.25 volts on my meter. Not sure if thats normal or if voltage is any way to test this converter. It was late last night when I was last at the boat and I cant recall
if I tried swapping the +/- wires on the NMEA in side but I think that did not help.
The seatalk to NMEA converter came with the boat at was working a few years back before I removed an old Northstar GPS that was being used to supply GPS data so I know it worked at some point...
Im thinking I should be seeing the green LED lit on the converter if it was working correctly?
Thanks for any help here.