Re: LF: Selection of spot frequencies for DX

["Alberto di Bene" <dibene@usa.net>]

James Moritz wrote:
> Not sure
> about ZL, but here in the UK the 50Hz nominal mains frequency  drifts around
> quite a bit - perhaps a few tenths of 1%. Seen on a fairly  coarse resolution
> spectrogram, the harmonics give a series of wavy lines  spaced by 50 or 100Hz,
> which drift enough to give overlapping coverage  during a period of a few
> minutes. But with very narrow resolution  spectrograms, this just adds to
> the "wide band" noise level, rather than  producing well-defined spectral
> lines, because the frequency does not  remain within one FFT box for long
> enough to produce a line.
Just for curiosity, I visualized the 53rd harmonic of the 50 Hz here in my
QTH,
and this is the result.  An unidentified signal is also present.

73  Alberto  I2PHD