Return-Path: <majordom@post.thorcom.com> Received: (qmail 12418 invoked from network); 25 Jan 2001 00:15:34 -0000 Received: from unknown (HELO murphys-inbound.servers.plus.net) (212.159.14.225) by extortion.plus.net with SMTP; 25 Jan 2001 00:15:34 -0000 Received: (qmail 12433 invoked from network); 25 Jan 2001 00:18:19 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys with SMTP; 25 Jan 2001 00:18:19 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from majordom by post.thorcom.com with local (Exim 3.16 #1) id 14La18-0001oj-00 for rsgb_lf_group-outgoing@blacksheep.org; Thu, 25 Jan 2001 00:11:58 +0000 Received: from imo-r05.mx.aol.com ([152.163.225.5]) by post.thorcom.com with esmtp (Exim 3.16 #1) id 14La16-0001oe-00 for rsgb_lf_group@blacksheep.org; Thu, 25 Jan 2001 00:11:57 +0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from DL4YHF@aol.com by imo-r05.mx.aol.com (mail_out_v29.5.) id l.6b.ef3f21c (7065) for <rsgb_lf_group@blacksheep.org>; Wed, 24 Jan 2001 19:09:56 -0500 (EST) From: DL4YHF@aol.com Message-ID: <6b.ef3f21c.27a0c8d4@aol.com> Date: Wed, 24 Jan 2001 19:09:56 EST Subject: LF: Final update on FM 19kHz pilot tones To: rsgb_lf_group@blacksheep.org MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 8bit X-Mailer: AOL 4.0.i for Windows 95 sub 69 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: <majordom@post.thorcom.com> Just a final update on the 19kHz FM stereo pilot tone (compared to TV sync). If you are not interested in this subject, please stop reading here or click on the delay button of your Email browser. Or explain to me why if it is completely "off-topic"... ( IMHO it's just a very little "off-topic" ;-) The stereo pilot tone used by FM broadcast stations is quite accurate for the large FM stations, and some may be useful for us as a cheap frequency reference, BUT (as Alberto 'PHD already thought): You have to find a station which produces an accurate frequency. In north western DL, I could not even find two with exactly the same pilot frequency. Just a few samples (without "absolute" accuracy, just to show the difference: WDR1: 19000.00 Hz (I used this as a pseudo-reference for the soundcard) WDR2: 19000.27 Hz (same company, other transmitter, 14 ppm off ?! ) WDR4: 19000.12 Hz (...) BFBS: 19000.07 Hz (British Forces Broadcasting Service) Maybe BFBS uses the the same stereo pilot tone as the BBC in London. WDR is one of the largest broadcasting companies in DL, but even they seem to differ from each other. (Compared to the accuracy of some well-equipped 'big guns' on LF, one may say the commercial broadcasters have lousy accuracy ). To verify that these differences are not propagation effects, I also compared some the TV line frequences (using a soundcard at 44100samp/sec, mixed down, decimated by 81, 64k FFT size, 0.008Hz resolution). All TV stations were received 'old style' via antenna. The TV line synch frequencies found this way (using the same "correction factor as above): ARD: 15625.18 Hz ZDF: 15625.19 Hz WDR: 15626.18 Hz RTL: 15626.20 Hz The difference between these signals are still above 1ppm (!?), but this may be based on propagation effects (It's not the measurement, I verified by switched the stations and watching the effect on the waterfall). Hope to meet you on the band in regular CW next weekend, even if it is our 10th QSO ! 73's Wolf (DL4YHF, DF0WD)