To verify there are no problems with the HDOP, you could try wiring up a d-sub 9 pin connector to the unit and via a usb to 9 pin connector, record the NMEA 0183 GSA data string (or similar string containing HDOP etc) on a windows based terminal (eg putty or hyper term). you can then investigate various GNSS accuracy values. I presume from your earlier posts you have enabled the EGNOS SBAS. I have done this to my elite-7 and it recorded the strings with no problems. Will be comparing it against data from an external Lowrance point-1 antenna when I fit it on my next leave.


As you can see from my picture, I'm one of these 3-d seismic surveyors - a bit more equipment than 1 40m analogue streamer for us! Can go up to 20 x 8000m streamers at 100m separation.

Getting 20 x 8000m streamers at 100m separation deployed must be a real nightmare, ghaaaa!!!
I guess it takes a couple of days and after that you don't change course for anything ;)

This error maps exactly to a time delay in the processing and it's extremely unlikely to get an position error that follows the boat like this so I'm really convinced that Lowrance has problems.

I have change to a GPS compass from Hemisphere, excellent position and heading and it has a very nice software gui where you can monitor and configure all kinds of stuff. The GPS compass has 2 RS232 ports and I route it through a custom made NMEA switch which has loads of inputs for RS232, 5 i/o for NMEA0183 and one CAN for NMEA2000. From that NMEA switch I send data to Lowrance Gen2 Touch at 10Hz with very low delay.

/hakan