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Re: LF: Luxembourg effect caused by DRM?

To: <[email protected]>
Subject: Re: LF: Luxembourg effect caused by DRM?
From: "Markus Vester" <[email protected]>
Date: Sat, 25 Dec 2010 11:50:24 +0100
Importance: Normal
References: <07CAB115732B40F59D87897A3301DDE3@Silver>
Reply-to: [email protected]
Sender: [email protected]
Picking up an old thread, but perhaps still interesting... 
 
The "digital Luxembourg" noise caused by DRM on 177 kHz are visible during many nights from 1.00 to 4:00 UT. Unrelated to this, also the strange 1.64 kHz ICM bands are often noticable. I have added two newer screenshots with annotations, and with RDF colours swapped for better visibility:
 
 
Best wishes,
Markus (DF6NM)
 

Sent: Saturday, February 21, 2009 11:55 PM
Subject: LF: Luxembourg effect caused by DRM?

Dear LF,
 
during parts of most nights, the Luxembourg crossmodulation shows a regular banding structure across a wide frequency range, quite unlike the typical patterns of AM music modulation:
The band spacing matches the subcarrier spectrum for "Mode A" DRM digital modulation (204 carriers spaced 41.66 Hz). A likely "heater" candidate would be Zehlendorf 177 kHz, which has been reported in DRM mode after midnight - could someone perhaps confirm the times of digital operation?
 
Another "mystery" noise band sometimes appears at night, about 200 Hz wide centered on 137.07 kHz, and of easterly origin (red):
In this capture, there is also a weaker replica of this band centered on 137.19 (north, violet). This combination would suggest Luxembourg effect on both HGA22 (east) and DCF39 (north), caused by a common heater carrying 1.64 kHz AM modulation. However I have no clue to what the source is, and why it would carry such an unusual modulation spectrum.
 
Kind regards,
Markus, DF6NM
 
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