[SFDXA] GPS week rollover, may affect your GPS device

[Kai]

This may affect you if you use a GPS dongle to set your computer clock (as for 
FT8, JT65, JT9,... all WSJT-X modes).

GPS Time as defined in the legacy GPS navigation message (ICD-200), uses 10 bits 
to count GPS Week Numbers. This representation can cover only a finite period of 
1024 weeks (19.7 year epoch).
• GPS Time started on Jan 6, 1980
• The first GPS Time Epoch ended on Aug 21/22 1999.
• GPS Time is presently in its second Epoch which will end on April 6, 2019

See:
https://www.gps.gov/cgsic/meetings/2017/powers.pdf

Cheers,
Kai, KE4PT