RE: LF: Fuzzy lines

["Dave Pick" <dave@picks.force9.co.uk>]

Markus

 

Interesting. The frequencies are right. I could understand the Rugby one because that's loud here but neither DCF39 nor Lessay are loud enough to intermod locally so where does that product get generated?

 

Dave G3YXM

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From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of MarkusVester@aol.com
Sent: 05 November 2005 22:04
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Fuzzy lines

Dear Dave and LF,

this seems to be an intermodulation between DCF39 (abt 0.1Hz wide due to the data telegrams every 10s) and Loran C. The lines in you screenshot are
138830.03 - 142 * 50000 / 6731 = 137775.21 (Lessay, Soustons, Sylt, Rugby) and
138830.03 - 158 * 50000 / 7499 = 137776.56 (Sylt, Lessay, Verlandet).
The latter one is a little surprising because Rugby does not appear to be dual rated.

Laurence KL1X saw similar DCF ghosts in December 2003, which appeared every time the path was open from Germany to Alaska. For a while we speculated about possible ionospheric crossmodulation, but then Laurence confirmed that the spurs were caused by periodic triggering of his noise blanker on the Pacific Loran pulses. We also found a faint hint of a Sylt + DCF39 combination in one of Alan's screenshots.

Hope this helps...

73 de Markus, DF6NM


In einer eMail vom 05.11.2005 21:03:36 Westeuropäische Normalzeit schreibt dave@picks.force9.co.uk:

Dear all

Myself and Gary G4WGT both see these fuzzy lines on Argo. I seem to remember
some discussion of their origin before but can't remember whether there was
a definite answer.
The come in at dusk and stay 'till dawn!

73
Dave G3YXM.