Re: Setting time on QCX - wspr mode


Hans Summers
 

Hello Gerry
 
Thanks Alan for your reply. As I see it the 27mhz update from the GPS stream ensures an accurate transmission frequency. The 20mhz osc is updated by the GPS serial data stream (to quote
Hans from the manual) to ensure a stable time lock. I was just puzzling why if the 27mhz update is displayed, why is the 20mhz update not displayed also. Is this just a function of the QCX programme and it was never intended to display it? I know that the clock is in fact being updated as it is set accurately after the first WSPR transmission and I presume after each and every subsequent transmission.. 

The 20MHz crystal is not calibrated during the regular GPS calibration at the end of each WSPR transmission. Only the real time clock (RTC) is set. It is not necessary to calibrate the 20MHz crystal every time since any minor frequency deviation due to temperature drift will cause an irrelevant time shift during WSPR operation. 

20MHz crystal calibration using the GPS is possible in the alignment menu. It is enough to do this once when setting up the radio after assembly. It is not even necessary to do this, since even a few kHz of error will still have no important impact on timekeeping in the short-term (between RTC updates by the GPS at the end of each cycle). 

73 Hans G0UPL
http://qrp-labs.com

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