Return-Path: X-Spam-DCC: paranoid 1290; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, FORGED_RCVD_HELO autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id t0DKggP4000621 for ; Tue, 13 Jan 2015 21:42:42 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1YB8C2-00066G-1O for rs_out_1@blacksheep.org; Tue, 13 Jan 2015 20:36:02 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1YB8C1-000667-LS for rsgb_lf_group@blacksheep.org; Tue, 13 Jan 2015 20:36:01 +0000 Received: from lb2-smtp-cloud6.xs4all.net ([194.109.24.28]) by relay1.thorcom.net with esmtps (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.84) (envelope-from ) id 1YB8C0-0008S5-2u for rsgb_lf_group@blacksheep.org; Tue, 13 Jan 2015 20:36:00 +0000 Received: from pc-roelof.fritz.box ([83.162.220.82]) by smtp-cloud6.xs4all.net with ESMTP id fYbx1p0091nG4D701Ybyks; Tue, 13 Jan 2015 21:35:59 +0100 To: rsgb_lf_group@blacksheep.org References: <3E493C075A3040DD8909A368EA72B512@gnat> Date: Tue, 13 Jan 2015 21:35:57 +0100 MIME-Version: 1.0 From: "Roelof Bakker" Message-ID: In-Reply-To: <3E493C075A3040DD8909A368EA72B512@gnat> User-Agent: Opera Mail/1.0 (Win32) X-Scan-Signature: fc152e7304849b9a177649b85aea9f41 Content-Type: text/plain; charset=iso-8859-15; format=flowed; delsp=yes Subject: LF: D-Layer and Propagation Content-Transfer-Encoding: 7bit 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-Scanned-By: MIMEDefang 2.56 on 10.1.3.10 Status: RO X-Status: X-Keywords: X-UID: 1974 Hello Alan, I have been given your article "A possible way of Forecasting good Radio Propagation conditions on 136kHz" a good thought over. Generally speaking the Kyoto Dst figures are a good indicator for LF reception in the NDB band (200kHz - 520kHz). I have used these to good effect the last couple of years. What has puzzled me is that after a solar disturbance propagation from NDB's in northern Canada is restored much quicker than from stations at a lower latitude. The last weeks the sun has been eruptive and T/A propagation has been about the worst as I remember. Since two days propagation is getting better, but only for Canadian NDB's above about 50 degrees north. Last night, I heard 21 Canadian NDB's of which the majority is located above 55 degrees north. Also one NDB from the north bank of Alaska was heard. At the same time nothing was heard from latitudes below 48 degrees. This also applies to Canadian and USA NAVTEX transmissions on 518 kHz. It has also been quite some time since there has been WSPR reception from USA stations in Europe. It is clear that long haul (aural) reception of Canadian NDB's above 48 degrees north has been excellent, whilst reception below this latitude has been nil. In your article you state "My observations, confirmed by reference to professional papers on the subject, suggest that there is an excess of absorbing ionisation in the D-layer, through which night-time signals must pass before being returned earthwards by refraction in the lower boundary of the E-layer. This absorbing D-layer ionisation seems to remain for some time after the geomagnetic conditions recover." In winter the daily build up of the D-Layer is much weaker at higher latitudes. This might be the reason that the effects of absorbing ionisation due to solar disturbances lasts not as long as at lower latitudes. Best regards, Roelof Bakker, PA0RDT