Amplitude, Phase, and Doppler Effects on WWV Reception

[uploadJ]

Rayleigh Fading - maximum signal peaks of about 6 dB, but fades that have nulls that can be 30 or more dB in depth; seems to be what happens with HF fading too. 5/5

[msf60khz]

When two signals nearly cancel, the residual signal is in quadrature. There is always a rapid 180 shift associated with a null, in antenna patterns, transmissions lines etc etc. In the WWV case, if signal strength variation occurs there are probably two paths . However, even if just one path, as it varies in length it will cause the ellipse to vary from circle to straight line.

[5UP7]

Yes, the video implies that brief and deep fades on HF are the result of the signal splitting into multiple paths that arrive at the receiver at equal amplitude, but opposite phase.

Occasionally, the signal "peaks" very suddenly as the amplitude of the signals add perfectly in phase.

Since VHF/UHF mobile picket fencing is a product of multipath reception, it might result in a similar amplitude and phase plot.

[hyvahyva]

Very interesting... I'm guessing the deep fades are probably due to changes in the ionosphere's level or movement of reflective nodes?

I kept thinking this looked a lot like the 'picket fencing' you get when the signal begins to flutter on a vhf/uhf mobile.