Hi Alberto,
You wrote: >Chris, > just a suggestion. Tune to WWV with Winrad, and set it to ECSS >mode. This > will activate >the round phase display below the S-meter. And the corrections to the >>frequency caused >by the ECSS algorithm have a granularity well below 1 Hz, even though >the >display on the >top is limited to 1 Hz resolution. For maximum precision bring the >tuned >station at the center >of the display by pressing Ctr-C after having tuned it. >I would be interested in knowing which improvements to this kind of >display >you would like >to see implemented in a future SDR program. Thanks. >73 Alberto I2PHD I have tried ECSS on WWV and it certainly provides the fastest way to get a frequency measurement - and very good reception of the WWV voice announcements. If it read to 0.1Hz it would be excellent. But I suspect that maybe propagation variations might then result in quite unstable readings? Maybe a longer time constant would provide a stable frequency display? My suggestions: 1) Retain your excellent ECSS mode - maybe with longer time constant if this is practical. This would be to avoid least significant digit jumping around. 2) Increase LO and Tune displays to 0.1Hz resolution. 3) Add a pop up window phase display like Sigmira which works in AM/USB/LSB modes. This allows graphical display of phase with both long and short term effects visible at the same time. Then user can make best judgement as to actual frequency with noisy signal propagation problems, etc. 4) Add a manual calibration mode to correct the inherent error of the SDR NCO as determined in (3) above. With the limited performance of the SDR-IQ NCO of course this calibration will need to be repeated whenever good accuracy is needed. Otherwise the correction is stored for next time the software is used. 5) Notch filter(s) manual and auto for the lower windows. 6) Consider the Rocky spectrum display format for upper window - as an option maybe? 73, Chris ZL1BOE
