RE: LF: 74550

[Bob Raide <rjraide@hotmail.com>]

Markus;
Glad to hear your results-just one of those nights but I noticed some decent captures that have not shown before.
Tonight will be interesting-Bob
 

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From: markusvester@aol.com
To: rsgb_lf_group@blacksheep.org
Date: Sun, 8 Dec 2013 20:40:42 +0100
Subject: LF: 74550

Hi Bob, all,

 

yes I noticed the QSB last night - perhaps a bit unfortunate that I had opted for slower speed just then.

 

On the other hand, I managed to catch several characters this time. Pretty much the best here ever since you've started, even without postprocessing. The longer dots have certainly helped. Last night's results have been uploaded to the usual folder

 df6nm.bplaced.net/LF/74kHz/

 

The effect of DCF noise cancellation can be seen in

 df6nm.bplaced.net/LF/74kHz/DCF77_PRN_cancellation/sp_both_131207-08.png

(also currently still shown on the 74kHz upload). Scales are 7.63 mHz and 60.5 seconds per pixel (50% overlap), and 20 dB brightness range. The top half is the raw spectrogram, the bottom after noise cancellation. The gap around Bob's frequency appears to have been one of the clearer parts in the first place, so the benefit from processing is not very conspicuous there. For anyone interested in the algorithm, there's also a pdf printout of the MathCad script:

 df6nm.bplaced.net/LF/74kHz/DCF77_PRN_cancellation/DCF2f.pdf

 

Between 22 and 7 UT, many parts from the XRS4 transmissions were readable. Traces from Dex also became visible on 74548.5 Hz, between 2 and 3 UT. Compared to former captures, this is a very satisfying result for me.

 

For the night to come, I'm set up for monitoring opds-64 in a 4 Hz slot around 74.55 kHz, and will be uploading screenshots and possible detections to the usual opds grabber http://dl.dropboxusercontent.com/u/26404526/opds.htm

In case others want to try: SpecLab FFT settings can be similar to opds-32 but more decimation is needed for half bandwidth (0.238 mHz). In opds.ini, center frequency and decimation should be edited: fc=74550, dec=50331648 .

 

Best 73,

Markus (DF6NM)

 

From: Bob Raide

Sent: Sunday, December 08, 2013 5:29 PM

To: rsgb_lf_group@blacksheep.org

Subject: RE: LF: 74550 12-08

Henny, Victor, Hartmut, Markus, et all;
Very up and down-worst QSB I have seen in a while.  Seems it was that way on all the bands, MF/LF.  The slower QRSS120 only made matters worse as couldn't get full call in before fade out-however, Markus needed slower mode to do some of his magic-hope it worked out73, Bob
 

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From: cpm@planet.nl
To: rsgb_lf_group@blacksheep.org
Date: Sun, 8 Dec 2013 10:03:19 +0100
Subject: LF: 74550 12-08

Gm,Bob,Dex,LF

 

The signals on 74550,

 

henny cpm

73's

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