----- Original Message -----
Sent: Sunday, January 06, 2013 5:44
PM
Subject: Asymmetric Luxembourg Effect on
HGA
On the occasion of watching the LF band on
the Twente WebSDR, I noticed an unusual Luxembourg effect on the HGA
carrier 135.43 kHz. In addition to the "normal" ICM mumbling which is
muffled and symmetrical on both sidebands, the lower sideband carries a
relatively strong and wideband modulation. A quick listening scan of strong BC
stations shows that the modulation coincides with 639 kHz from Prag,
which is radiating 750 kW from a pair of 355 m high antennas. The
geographic constellation (Budapest - Prag - Holland) looks plausible for
ionospheric heating, but I have no explanation whatsoever for that one-sided
spectrum!
Best 73,
Markus (DF6NM)
