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Re: LF: Selection of spot frequencies for DX

To: [email protected]
Subject: Re: LF: Selection of spot frequencies for DX
From: "Alberto di Bene" <[email protected]>
Date: Mon, 24 Mar 2003 15:43:06 +0100
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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

JPEG image

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