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Paul Nicholson put forth the important argument
that we'd better stay away from 8280 because it's a multiple of 60
Hz. Mains harmonics tend to drift a bit with the line frequeny so further
away is better.
Thus I retract my preposition, and suggest instead
to stay with the original 8270 Hz.
Uwe, go ahead!
Best 73,
Markus
PS Direct harmonics from 16.67 Hz are relatively
weak here, even though the railway is only 400 m away. It looks
more like carriers from switchmode power conversion units
(eg near 8 kHz), accompanied by the telltale 33 Hz spaced sidebands.
Unfortunately these frequencies are not easily predictable.
Sent: Friday, January 03, 2014 12:56 PM
Subject: Re: VLF: 8.275 kHz
8970 is well placed with respect to harmonics of
both 50
and 60Hz.
8270/8275 not so good in a 60Hz region.
8124 to 8126
would be a good range, considering
harmonics of 16.67Hz, 50Hz, and
60Hz.
Let me know what is decided, I will switch my spectrogram
over
to the new band.
--
Paul Nicholson
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