Hi all, Gunnar, sa6bqz, noticed yesterday that his position beacons from his AIS and pskmail systems differed somewhat. There was abt 18 meters difference between them. I investigated this issue somewhat today and figured it best to post a short notice here should anyone else start to notice something similar. The GPS delivers position data through the nmea GGA message (and others). The position message format for NMEA GGA is like llll.ll,a,yyyyy.yy,a. A real world example of that is what I get here: 5901.3658,N,01756.0467,E. When we transmit this we have to format it in accordance with the APRS protocol spec. That spec says that the latitude format should be: "Latitude is expressed as a fixed 8-character field, in degrees and decimal minutes (to two decimal places), followed by the letter N for north or S for south." To create a concrete example for APRS the position is formatted like: 5901.37N. And there we have it in a nutshell, NMEA data 5901.3658 gets reported as 5901.37 and a slight difference in position is noticeable (not the rounding, thats expected). Also, when looking at this I would prefer to never use the decimal position format. Incoming NMEA is in degrees and minutes, outgoing APRS is in the same format (less precise but still degrees and minutes). Decimal degrees as presented in jpskmail is never used, only presented. My sailor eyes hurt when looking at the decimal format but I guess some want it anyway? 73 de Per, sm0rwo P.s. Spending the afternoon painting the boat.