Hi Chris, > > I do not understand the purpose of a phase indicator. > > It would be hard for me to explain properly with my limited > technical background but if you try the Sigmira program with the > phase display running on WWV you should see what I mean. I have uploaded a page with some high resolution waterfalls of WWV. It is pretty obvious what a phase indicator would have shown, but I think the waterfall is far more informative:-) http://www.sm5bsz.com/linuxdsp/usage/cal10/cal10.htm
> I find after a bit of practice that I can visually distinguish > the average phase state from the often complex instantaneous > phase variations. I think this is because the Sigmira phase > display contains much more information - both short term > and longer term phase variations can be seen at the same time. Yes, and more so in the waterfall. > After using the Sigmira calibrate routine I can tune my SDR-IQ > to read WWV correct to within 1Hz on the frequency display. By feeding the frequency error (1.1 Hz at 10 MHz => 88Hz for the Perseus sampling frequency) into the program, the Linrad frequency scale would be correct within the uncertainty of the ionospheric propagation frequency shift. The frequency readout is in 0.1 Hz steps but you could easily read within 0.01 Hz from the frequency scale if you expand it a little. 73 Leif / SM5BSZ
