Return-Path: Received: (qmail 18788 invoked from network); 30 Jan 2002 10:37:17 -0000 Received: from unknown (HELO murphys-inbound.services.quay.plus.net) (212.159.14.225) by excalibur-qfe1-smtp-plusnet.harl.plus.net with SMTP; 30 Jan 2002 10:37:17 -0000 Received: (qmail 25935 invoked from network); 30 Jan 2002 10:37:19 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys.services.quay.plus.net with SMTP; 30 Jan 2002 10:37:19 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 16VrzE-0004pg-00 for rsgb_lf_group-outgoing@blacksheep.org; Wed, 30 Jan 2002 10:29:04 +0000 Received: from tungsten.btinternet.com ([194.73.73.81]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 16VrzD-0004pb-00 for rsgb_lf_group@blacksheep.org; Wed, 30 Jan 2002 10:29:03 +0000 Received: from host62-7-55-165.btinternet.com ([62.7.55.165] helo=default) by tungsten.btinternet.com with smtp (Exim 3.22 #8) id 16VryP-000352-00 for rsgb_lf_group@blacksheep.org; Wed, 30 Jan 2002 10:28:14 +0000 Message-ID: <001d01c1a978$cb5fafe0$a537073e@default> From: "Alan Melia" To: "LF-Group" Subject: LF: Propagation Date: Wed, 30 Jan 2002 10:10:24 -0000 MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 4.72.3110.5 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Hi Rich, I am afraid that in my opinion the propagation conditions on 160m and LF are completely different. There may be some features that are the same but (and I may be wrong here) I believe that long distance 160m is mainly propagated by F layer reflection whereas LF does not penetrate the E-layer. Most LF propagation seems to be by 'reflection' from the bottom of the E-layer (at night) or from the lower regions of enhanced ionisation in the D-layer (daytime). Since early December, there has been evident in Brian's (CT1DRP) plots of DCF39 that there has been enhanced daytime signals (6 to 10dB above the average for early September ), and depressed night-time signals. These have been confirmed by occasional plots of CFH from my location, when It has appeared. The usual cause of the conditions described has been ions injected into to D-layer by the big geomagnetic storms. The after-effects of the storm can last up to 20 days, before, I presume, these energetic ions decay. The strange situation at present is that there has been little geomagnetic activity since late November to early December and yet the conditions at night has stayed depressed. There is a sign this morning that things are getting back to normal as I logged a carrier on 137,010 or there abouts which I assume is CFH. The overnight levels were better than they have been recently but there is still a lot of deep fading. These condition usually indicate the end of a propagation even and a return to 'normal' conditions. The fact that the carrier is still strong here at 1000z suggests that we are not fully clear of the ions that give enhanced day-time conditions yet. This enhacement of ionisation in the D-layer would also give increased absorption of 160m signals, but I guess the Hawaii station was talking about night-time paths. Cheers de Alan G3NYK alan.melia@btinternet.com