Re: LF: DCF39

[MarkusVester@aol.com]

Dear Alan and Geri,

... I have to confess that I had actually sent an eMail to the EFR back in 2000, suggesting 85% energy savings (and less Luxembourg QRM for us) by reducing idle carrier power by 13 dB (http://members.aol.com/df6nm2/to_efr.txt). For propagation monitoring in sub-Hz bandwidth you would of course get a weaker carrier, but probably not be disturbed by the power change during the relatively wideband FSK telegrams. Anyway I think their current instabilities seem to be related to technical problems rather than intentional actions.

One thing I have been pondering is that if we would record the carrier phase evolution locally and distribute it by internet, a distant monitoring station could use that information to deconvolve the received DCF signal and narrow it down from about 0.1 Hz to any sub-milliHz bandwidth, gaining at least 20 dB in sensitivity. We could reference the phase log to GPS-derived 138830 Hz, which would enable the use of coherent signal processing techniques as suggested by G3PLX and others. A practical data format could be IQ pairs at one sample per second, with a new file starting every full hour.

73 de Markus, DF6NM

In einer eMail vom 29.08.2006 11:55:50 Westeuropäische Sommerzeit schreibt alan.melia@btinternet.com: 

> Hi Geri, mmmm I hope not, because random changes in level will kill it as a
> useful beacon source, and relagate it to the category of QRM.
>
> Cheers de Alan G3NYK
>
> ----- Original Message -----
> From: Holger 'Geri', DK8KW <geri@dk8kw.de>
> To: <rsgb_lf_group@blacksheep.org>
> Sent: 29 August 2006 05:43
> Subject: Re: LF: DCF39
>
>
> Hello Markus,
>
> very interesting graph.
>
> I guess at the currently high energy costs someone at the Europäischen
> Funkrundsteuerung GmbH (EFR) must have started to think if it is really
> necessary to put a 40 to 50 kW permanent carrier on the air to remotely
> switch on and off street lamp. These 3 dB steps might be tests for a system
> to reduce the carrier level at least between the telegrams to save costs.
>
> Best 73
>
> Geri, DK8KW / W1KW / DI2BO