On 23/11/16 11:16, MaverickNH wrote: > Looking at WSJT-X 1.7rc2 ALL_WSPR log and seeing RX frequencies such as > 14.0971282. Seems like too many digits unless reporting 10th of a Hertz as > in 14,097,128.2 Hz. Perhaps this is calculated as an average over the RX > window? > > Looking at the log for RX over 500+ RXs, I find the RX frequency range is > 206Hz. Actual TX 14,097,037 and average RX at 14,097,110, or +73Hz. > > I have a GPSDO managed PC clock as well as a GPSDO managed frequency > oscillator in my K3S transceiver, so my regulation is pretty tight. > > What are the major components of the deviation in reported RX frequency? I > posted on WSPRnet also, but one seldom gets replies there on any posts.
There are errors at the TX end, errors at the RX end and errors in the middle: ionospheric doppler shift. With a K3S + GPSDO, the biggest source of RX error might be the tolerance of the sampling frequency of the sound card. The built-in USB sound card has a 100ppm clock crystal, corresponding to ±0.15 Hz @ 1500 Hz. -- Richard G4DYA ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
