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+--- Thread: Max Error computation bug? (/showthread.php?tid=470)
Max Error computation bug? - ve3ktn - 05-21-2020
Hello everyone,
I'm quite pleased with BktTimeSync 1.11.1 as it has lots of control over the time source selection and the methods for accurately syncing the PC clock. The ability to shift the PC clock time by very small amounts using the Manual Set control is especially useful when operating FT4 and 8. There is something I'm not sure about with respect to how the "Max Error" value is treated. It seems that the code only checks for positive values of (GPS_time) - (PC_time). E.g. I think the test is:
IF (GPS_time)-(PC_time) > Err_value THEN .....
which is wrong IMO. The test should be:
IF ABS((GPS_time)-(PC_time)) > Err_value THEN ....
Mauro, I would be grateful if you would confirm or check this. What I am seeing is that if the PC Clock time is a larger positive value than Max Error, then it reads the GPS receiver time again and continues to read it until the PC_Time - GPS_Time is less than Max Error, but if PC_Time - GPS_Time is a negative value whose magnitude is larger than Max Error, it does not read the GPS receiver again. Also, why is this function restricted to time coming from a GPS receiver? Should it not also apply to NTP, or is the reasoning that NTP should be taken for granted as accurate?
Thank you, kind regards, and 73,
Hugo - ve3ktn.
RE: Max Error computation bug? - iz2bkt - 05-21-2020
Hi Hugo,
the problem of maximum error control in GPS has been resolved by version 1.11.2.
Synchronizing with the NTP internet protocol does not require a time correction.
RE: Max Error computation bug? - ve3ktn - 05-27-2020
Dear Mauro, Thank you very much for the quick action to correct the GPS Max Error bug. Since my original message, I have been doing some tests on BktTimeSync and have additional feedback for you. These are observations from using V1.11.2 since I downloaded the update on 2020-05-24. I hope these are useful to you for a future update of this software.
Cheers, 73,
Hugo, ve3ktn.