After todays sail my max GPS readout was 33.76 knots
When i download it to computer i got a max of 38.576 knots
It seems right when i look at the track so am happy it is not a spike.
does anyone else have such huge differences between GPS Display and what your computer tells you at home.

Thanks in advance

P.S.
Well done to everyone that got PBs today it was a great day at Hardies

Hey mate,

You've probably been a victim of the algorithm the NAVI uses to figure out where it is. Occasionally it switches satellites and suddenly realises it's a way away from where it thought it was, so it compensates by drifting to the new position over about ten seconds. Sometimes this makes your speed increase, sometimes decrease.

If you use "Doppler" to calculate your values then the error is much reduced.

Remember the GPS is only a verification tool, you should know the difference between 33 and 38 knots...

problem sorted
it was settings in realspeed not using doppler to calculate results.
thanks Nebs