GPS ANTENNAE

IS AN EXTERNAL ANTENNAE MORE ACCURATE THAN THE INTERNAL ANTENNAE?

if in the same place i dont know. i do see a lot of external mounted on the rear of the boat, 7-10 feet from the unit that could make a slight difference.

I can only speak about helix. But the helix external allows you to display waypoints on 360 etc.. There might be other benefits but I dont remember them anymore.


I have mine on the back of my boat almost above the ducer, it doesnt really matter since I cursor over and mark brush on the brush etc, so my way points would be accurate using either...

Don't they do something with making the direction of the boat on the GPS screen show correctly even if the boat is not moving?

There are external GPS antennas, external GPS/Heading Sensors, and external Heading Sensors.

A Heading Sensor (compass) does that.
GPS cannot calculate Coarse direction when at less than .6 mph.
Humminbird units change the position curser to a O when that happens. A heading sensor keeps the position curser active and if installed correctly, indicates the direction the bow is pointed==very handy when fishing offshore waypoints.

Humminbird units can use an external GPS/Heading Sensor (AS GPS HS) directly connected, Minnkota iPilot LINK via Ethernet connection, and a Lowrance Point1 via NMEA2000

It does matter. No they will not have the same accuracy.
A waypoint is created and located by a GPS antenna.
If you see a subject with sonar/Imaging and mark it, the location will be in relation to the GPS antenna. If that antenna is at the console, that's a created error of the distance between the sonar transducer and GPS antenna.

Used to be but not anymore, the early generation stuff from 2000 to mid 2000's the external were definitely more accurate. The internal gps now are just as good.