Re: LF: Selection of spot frequencies for DX

["Rik Strobbe" <rik.strobbe@fys.kuleuven.ac.be>]

The picture seems to confirm Jim's remark, a variation of 1-2Hz at the
53rd harmonic results is a variation of 50-100Hz at the 2740th harmonic
(137kHz)

73, Rik  ON7YD

At 15:43 24/03/2003 +0100, you wrote:

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