I agree that for some, requiring a double check would interfere with the user experience. That's why I am suggesting this feature be a user configuration option. The user can then determine whether they want protection or convenience. Everybody wins.

Here is a snip of data from a GPS that does work: $GPGSA,A,3,06,29,24,48,11,12,19,05,25,,,,1.62,0.90,1.35*07 $GPGSV,4,1,13,05,22,162,27,06,29,042,32,11,71,047,34,12,77,336,41*73 $GPGSV,4,2,13,19,13,072,33,20,42,137,42,22,00,130,,24,25,210,18*7C $GPGSV,4,3,13,25,45,316,23,28,05,323,,29,21,280,13,46,49,198,*7D $GPGSV,4,4,13,48,50,190,29*41 $GPGLL,3422.07620,N,11903.95116,W,155731.00,A,D*7E $GPRMC,155732.00,A,3422.07617,N,11903.95125,W,0.260,,180624,,,D*6D $GPVTG,,T,,M,0.260,N,0.482,K,D*2C $GPGGA,155732.00,3422.07617,N,11903.95125,W,2,09,0.90,188.1,M,-32.9,M,,0000*6F $GPGSA,A,3,06,29,24,48,11,12,19,05,25,,,,1.62,0.90,1.35*07 $GPGSV,4,1,13,05,22,162,27,06,29,042,32,11,71,047,33,12,77,336,41*74 $GPGSV,4,2,13,19,13,072,33,20,42,137,41,22,00,130,,24,25,210,18*7F $GPGSV,4,3,13,25,45,316,22,28,05,323,,29,21,280,12,46,49,198,*7D $GPGSV,4,4,13,48,50,190,30*49 $GPGLL,3422.07617,N,11903.95125,W,155732.00,A,D*79 $GPRMC,155733.00,A,3422.07615,N,11903.95122,W,0.130,,180624,,,D*6F $GPVTG,,T,,M,0.130,N,0.241,K,D*23 $GPGGA,155733.00,3422.07615,N,11903.95122,W,2,09,0.90,188.2,M,-32.9,M,,0000*68 $GPGSA,A,3,06,29,24,48,11,12,19,05,25,,,,1.62,0.90,1.35*07 $GPGSV,4,1,13,05,22,162,27,06,29,042,32,11,71,047,34,12,77,336,41*73 $GPGSV,4,2,13,19,13,072,33,20,42,137,42,22,00,130,,24,25,210,18*7C $GPGSV,4,3,13,25,45,316,22,28,05,323,,29,21,280,11,46,49,198,*7E $GPGSV,4,4,13,48,50,190,31*48 $GPGLL,3422.07615,N,11903.95122,W,155733.00,A,D*7D $GPRMC,155734.00,A,3422.07612,N,11903.95129,W,0.146,,180624,,,D*65 $GPVTG,,T,,M,0.146,N,0.270,K,D*20 $GPGGA,155734.00,3422.07612,N,11903.95129,W,2,09,0.90,188.1,M,-32.9,M,,0000*60 $GPGSA,A,3,06,29,24,48,11,12,19,05,25,,,,1.62,0.90,1.35*07 $GPGSV,4,1,13,05,22,162,27,06,29,042,32,11,71,047,35,12,77,336,41*72 $GPGSV,4,2,13,19,13,073,33,20,42,137,42,22,00,130,,24,25,210,19*7C $GPGSV,4,3,13,25,45,316,22,28,05,323,,29,21,280,11,46,49,198,*7E $GPGSV,4,4,13,48,50,190,31*48 $GPGLL,3422.07612,N,11903.95129,W,155734.00,A,D*76

Thanks.

Issue has been resolved. It was caused by a corrupted MAC address table in my Gigabit ethernet swtich. By trying a direct Cat 7 cable between my PC and radio which worked fine, I able to narrow the issue to something in my network.