Return-Path: Received: (qmail 32247 invoked from network); 30 Aug 2003 13:29:23 -0000 Received: from warrior.services.quay.plus.net (212.159.14.227) by mailstore with SMTP; 30 Aug 2003 13:29:23 -0000 Received: (qmail 12965 invoked from network); 30 Aug 2003 13:29:26 -0000 X-Filtered-by: Plusnet (hmail v1.01) X-Spam-detection-level: 11 Received: from post.thorcom.com (193.82.116.70) by warrior.services.quay.plus.net with SMTP; 30 Aug 2003 13:28:56 -0000 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 19t5lB-00017C-4C for rsgb_lf_group-outgoing@blacksheep.org; Sat, 30 Aug 2003 14:27:21 +0100 X-No-DNS-For: 212.1.130.142 Received: from [212.1.130.142] (helo=smtp-1.visp.telinco.net) by post.thorcom.com with esmtp (Exim 4.14) id 19t5l7-000173-5Q for rsgb_lf_group@blacksheep.org; Sat, 30 Aug 2003 14:27:17 +0100 Received: from [80.40.54.113] (helo=RSGB613192) by smtp-1.visp.telinco.net with smtp (Exim 3.36 #1) id 19t5l6-0005qD-00 for rsgb_lf_group@blacksheep.org; Sat, 30 Aug 2003 14:27:16 +0100 X-Bad-Message-ID: no DNS (RSGB613192) Message-ID: <002201c36efa$6e12a1a0$045bfea9@RSGB613192> From: "Andy talbot" To: rsgb_lf_group@blacksheep.org References: <5.1.0.14.0.20030829155231.02af4b10@gemini.herts.ac.uk> <5.1.0.14.0.20030830124931.02a8cdf0@gemini.herts.ac.uk> Date: Sat, 30 Aug 2003 14:27:13 +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 V6.00.2800.1106 Subject: Re: LF: Re: GPS-locked PSK tests Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, hits=-1.5 required=5.0tests=ORIGINAL_MESSAGE,QUOTED_EMAIL_TEXT,REFERENCESversion=2.55 X-Spam-Checker-Version: SpamAssassin 2.55 (1.174.2.19-2003-05-19-exp) X-SA-Exim-Scanned: Yes Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rsgb_lf_group-outgoing@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Spam-Rating: 2 Just for a bit of a challenge I've just set up the receiver monitoring DCF77 on 77.5kHz, with the Caesium beam turned on for the first time in over a year. It was very disconcerting to find that I was teh cause of the freqeuncy drift in last night's test ! Using just the crystal oscillator part of the freq standard resulted in 7*10^-10 frequency error. So far, after an hour of monitoring using a 30 second integration period, the vectorscope plot of DCF77 has not moved more than 0.1 degrees - and that is most likely due to quantisation effects I'll leave it running over the day-night transition and see what transpires. Andy G4JNT ----- Original Message ----- From: James Moritz To: Sent: Saturday, August 30, 2003 1:30 PM Subject: Re: LF: Re: GPS-locked PSK tests > For long distance communications, it will be interesting to see what effect > sky-wave propagation has on the stability of the phase of the signal - I > suppose this could be investigated by looking at some of the stable > broadcast signals thare are around - MSF, HBG, Droitwich, etc. Using this > type of system, it should be fairly easy to see the phase changes produced > by the ionosphere moving around. > I hope to do some more tests during the week with lower power levels, etc. > as G4JNT suggests. At the moment, the PSK signal is generated by simple > hard-wired logic - the length of the 12 bit "message" is fixed, but the bit > period can be changed quite easily. If anyone has ideas for interesting > experiments, please let me know. > > Cheers, Jim Moritz > 73 de M0BMU > >