Envelope-to: dave@picks.force9.co.uk Delivery-date: Sun, 24 Apr 2005 21:36:56 +0100 Received: from ptb-spamcore02.plus.net ([192.168.71.3]) by pih-mxcore12.plus.net with esmtp (PlusNet MXCore v1.0) id 1DPnqa-0002Nc-Bo for dave@picks.force9.co.uk; Sun, 24 Apr 2005 21:36:56 +0100 Received: from mailnull by ptb-spamcore02.plus.net with spamcore-l-b (Exim 4.32; FreeBSD) id 1DPnuj-0002n6-Lw for dave@picks.force9.co.uk; Sun, 24 Apr 2005 21:41:13 +0100 Received: from [192.168.101.73] (helo=pih-mxcore07.plus.net) by ptb-spamcore02.plus.net with esmtp (Exim 4.32; FreeBSD) id 1DPnuj-0002n3-Is for dave@picks.force9.co.uk; Sun, 24 Apr 2005 21:41:13 +0100 Received: from post.thorcom.com ([193.82.116.20]) by pih-mxcore07.plus.net with esmtp (PlusNet MXCore v1.0) id 1DPnqZ-0006zY-SJ for dave@picks.force9.co.uk; Sun, 24 Apr 2005 21:36:55 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1DPnq7-00064D-4D for rs_out_1@blacksheep.org; Sun, 24 Apr 2005 21:36:27 +0100 Received: from [193.82.116.30] (helo=relay.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1DPnq6-000644-Mm for rsgb_lf_group@blacksheep.org; Sun, 24 Apr 2005 21:36:26 +0100 Received: from smtp812.mail.ukl.yahoo.com ([217.12.12.202]) by relay.thorcom.net with smtp (Exim 4.43) id 1DPnq5-0008LG-79 for rsgb_lf_group@blacksheep.org; Sun, 24 Apr 2005 21:36:26 +0100 Received: from unknown (HELO w4o8m9) (james.moritz@btopenworld.com@81.135.4.168 with login) by smtp812.mail.ukl.yahoo.com with SMTP; 24 Apr 2005 20:36:18 -0000 Message-ID: <000b01c5490d$441ed140$a8048751@w4o8m9> From: "James Moritz" To: rsgb_lf_group@blacksheep.org References: <60.5441c725.2f9d551d@aol.com> Date: Sun, 24 Apr 2005 21:36:16 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.2615.200 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2615.200 X-SPF-Result: relay.thorcom.net: 217.12.12.202 is neither permitted nor denied by domain of btopenworld.com X-Spam-Score: 0.1 (/) X-Spam-Report: autolearn=failed,HTML_50_60=0.095,HTML_MESSAGE=0.001 Subject: LF: Re: Re: Divider by 10 or 100 for 136k out Content-Type: text/html; charset=windows-1252 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Status: No, hits=0.8 required=5.0 tests=HTML_30_40,HTML_MESSAGE autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Spam-Filtered: by PlusNet SpamCORE (v3.00) Content-transfer-encoding: 8bit
Dear Markus, LF Group,
 
You can see this on some amateur QRSS signals when they send a CW ID - the ones who are not keying dividers show up as a carrier with a blur around it, while the ones with keyed dividers are all blur and no carrier :-)
 
The same can be seen on the DCF39 "carrier" - with a high enough resolution spectrogram, this becomes a blur too, with a bandwidth of the order of 0.05Hz.
 
Cheers, Jim Moritz
73 de M0BMU
----- Original Message -----
From: MarkusVester@aol.com
To: rsgb_lf_group@blacksheep.org
Sent: Sunday, April 24, 2005 9:01 PM
Subject: LF: Re: Divider by 10 or 100 for 136k out

Dear Hans-Albrecht and Jim,

there is one minor disadvantage in keying a divider: As the phase at each key-down is arbitrary, the transmitted signal looses its inter-symbol coherence. This does not affect normal aural or visual decoding in any manner. But on a high-resolution FFT you will no longer be able to resolve a central spectral line, which would be useful to detect the presence of a very weak signal or precisely measure its frequency.

Of course the same holds true for small keying chirps, as I have recently learned :-(

73 de Markus, DF6NM