-----Ursprüngliche Mitteilung----- Von: Markus Vester An: rsgb_lf_group Verschickt: Sa, 25 Dez 2010 10:51 am Betreff: Re: LF: Luxembourg effect caused by DRM? 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: http://df6nm.bplaced.net/LF/ICM-DRM_101221_0110.jpg http://df6nm.bplaced.net/LF/ICM-1640Hz_101225_0245.jpg Best wishes, Markus (DF6NM) From: Markus Vester Sent: Saturday, February 21, 2009 11:55 PM To: rsgb_lf_group@blacksheep.org 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: http://www.alice-dsl.net/df6nm/test0902210320.png 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): http://www.alice-dsl.net/df6nm/test0902210100.png 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