Return-Path: Received: (qmail 29300 invoked from network); 21 Jan 2003 12:29:04 -0000 Received: from murphys.services.quay.plus.net (212.159.14.225) by mailstore with SMTP; 21 Jan 2003 12:29:04 -0000 Received: (qmail 16434 invoked from network); 21 Jan 2003 12:30:32 -0000 Content-Transfer-Encoding: 8bit Received: from post.thorcom.com (193.82.116.70) by murphys.services.quay.plus.net with SMTP; 21 Jan 2003 12:30:32 -0000 X-SQ: A X-Priority: 3 X-MSMail-Priority: Normal Received: from majordom by post.thorcom.com with local (Exim 4.12) id 18axTq-0003WD-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 21 Jan 2003 12:26:14 +0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from [147.197.200.9] (helo=hestia.herts.ac.uk) by post.thorcom.com with esmtp (Exim 4.12) id 18axTp-0003W4-00 for rsgb_lf_group@blacksheep.org; Tue, 21 Jan 2003 12:26:13 +0000 Received: from gemini ([147.197.200.44] helo=gemini.herts.ac.uk) by hestia.herts.ac.uk with esmtp (Exim 3.22 #1) id 18axTT-0000qu-00 for rsgb_lf_group@blacksheep.org; Tue, 21 Jan 2003 12:25:51 +0000 Received: from [147.197.232.252] (helo=rsch-15.herts.ac.uk) by gemini.herts.ac.uk with esmtp (Exim 3.33 #1) id 18axTS-0006F5-00 for rsgb_lf_group@blacksheep.org; Tue, 21 Jan 2003 12:25:50 +0000 Message-ID: <5.1.0.14.0.20030121110409.00a985b0@gemini.herts.ac.uk> X-Sender: mj9ar@gemini.herts.ac.uk X-Mailer: QUALCOMM Windows Eudora Version 5.1 Date: Tue, 21 Jan 2003 12:25:24 +0000 To: rsgb_lf_group@blacksheep.org From: "James Moritz" In-reply-to: <000e01c2c0be$f4054320$aac6e150@hughspc> References: <5.1.0.14.0.20030117183432.00af50f0@gemini.herts.ac.uk> MIME-Version: 1.0 X-MailScanner: No Virus detected Subject: Re: LF: Re: Re: Notch for DCF39/Spectrograms/Luxembourg effect Content-Type: text/plain; charset=us-ascii; format=flowed X-Spam-Status: No, hits=-2.0 required=6.0tests=DEAR_SOMEBODY,EMAIL_ATTRIBUTION,IN_REP_TO,REFERENCES, SPAM_PHRASE_00_01version=2.43 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 Dear Hugh, LF Group, At 22:57 19/01/2003 +0000, you wrote: >I notice the sounds and patterning on the screen are only there during the >hours of darkness, does that prove that it is the ionosphere and not the >radio ? >Does the ionosphere cause non-linear mixing of higher frequencies or just LF >? I believe it's called the Luxembourg effect because it was first observed on MF signals from Radio Luxembourg in the 20s or 30s. I don't know much about the field, but any frequency that is absorbed by the ionosphere will cause "heating", which modulates it's reflecting properties. There are number of research facilities which transmit megawatts of HF straight up in order to investigate ionospheric physics - searching the web under "ionospheric heater", "HAARP" or "EISCAT" will give you lots of hits, including the conspiracy theorists, who of course will tell you what the real purpose of these experiments is! The fact that the noises disappear during daytime, also that any amount of preselector filtering does not remove them, is quite convincing that these signals originate outside the receiver. >Have you tried out your buffer circuit - or is it just a "circuit idea" I >wonder ? Yes, it is a real circuit - I have not tried it with the notch filter, but I did test it as a high impedance antenna preamp, as well as the bench measurements I mentioned - it seems to do the job quite well, and since there are 4 medium wave broadcast stations within 1km of my QTH, it demonstrates the linearity must be OK! Cheers, Jim Moritz 73 de M0BMU