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Re: ULF: 11.6 µHz transmission

To: <[email protected]>
Subject: Re: ULF: 11.6 µHz transmission
From: "Markus Vester" <[email protected]>
Date: Mon, 2 Apr 2012 00:29:03 +0200
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Thanks to all who responded to this unusual news. Unlike other some other stories told today, this one is completely true!
It was triggered by the beautiful description of the oscillator on
However the frequency given there is slightly incorrect, as it was calculated from a 24 h solar day, instead of the slightly shorter rotation period in an inertial system.
The electromagnetic signal is caused by the earth's magnetic dipole moment (8e22 Am^2) rotating around the N-S axis at an 11 degree tilt angle. The radiation power from the rotating component can be calculated as
 2 * 0.5 * 31171 ohm * (8e22 Am^2 * sin(11°) )^2 / lambda^4 = 16 µW,
with the first factor of 2 for the "turnstile" configuration, equivalent to two loops fed in quadrature.
A report from the far field (1 lightday / 2pi) would certainly be good news for the SETI community ;-)
Congratulations to Jim for uncovering the Doppler modulation caused by annual motion of earth, an effect which I hadn't thought of. Depending on the position of an observer relative to the ecliptic, the 31.7 nHz sidebands due to this "Moritz effect" could be up to -35 dBc, which should be quite noticable ;-)
Happy springtime to all in the group,
Markus (DF6NM).

Sent: Sunday, April 01, 2012 8:28 AM
Subject: ULF: 11.6 µHz transmission

Dear LF,
in a joint project including a number of radio amateurs, our group is working on a large experimental earth-antenna system, which is able to radiate an ultra-low frequency signal at low power.
We are currently transmitting an unmodulated test carrier on 11.60576 µHz, and (according to our measurements) are achieving a radiated power of 16 microwatts. Frequency stability is on the order of 1e-8, which should enable narrow bandwidth observations with high sensitivity.
The transmission has been on air for a while. Any reception reports (especially of far-field detections) would be much appreciated.
Best 73,
Markus (DF6NM)
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