G4JNT wrote:

There is likely to be several Hz of Doppler shift on that frequency at night
time.

Right.
It is interesting to look at the carriers from various broadcasting powerhouses
on HF. Sometimes they spread out 10-20Hz or so, sometimes the same
stations produce a thin line on the spectrogram. Longer paths seems to
produce wider traces, as expected. It all depends on the mood of Mr. Doppler
who seems to depend on the mood of the Sun.

73
Johan SM6LKM