Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_MED,SPF_PASS,T_DKIM_INVALID autolearn=ham autolearn_force=no version=3.4.0 X-Spam-DCC: : mailn 1480; Body=2 Fuz1=2 Fuz2=2 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by lipkowski.org (8.14.4/8.14.4/Debian-8+deb8u1) with ESMTP id v39J7b3U015871 for ; Sun, 9 Apr 2017 21:07:39 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1cxI6m-0004q6-SB for rs_out_1@blacksheep.org; Sun, 09 Apr 2017 20:02:44 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1cxI6m-0004px-Ib for rsgb_lf_group@blacksheep.org; Sun, 09 Apr 2017 20:02:44 +0100 Received: from porthos.netcom.co.uk ([217.72.171.73]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1cxI6i-0004XX-Hr for rsgb_lf_group@blacksheep.org; Sun, 09 Apr 2017 20:02:43 +0100 X-DKIM-Result: Domain=abelian.org Result=Signature OK DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=abelian.org ; s=default; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:From:References:To:Subject:Sender:Reply-To:Cc: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=2v9O7XMiyITzKJHXwXnCJop9XVY2bMZXEtx+4DNdf6U=; b=EFCDu9d8aWoIgtqhaAMlfiNWGy dS1FKc2kLdTIOfHse5tXkwIW0L3IijpV+WnDuxs5rpfx7v3N2ocJVOUgTebkGUbXI3cAg9x9CRpQn jDxBvOEiAMJzqgoT6tx2LTwGn9PzeEcsCFLiMtizg20YfuCSHIhQQSr4oba0nJFItGqY=; Received: from i-194-106-52-83.freedom2surf.net ([194.106.52.83]:57914 helo=pn.abelian.org) by porthos.netcom.co.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.88) (envelope-from ) id 1cxI6h-0004HC-G3 for rsgb_lf_group@blacksheep.org; Sun, 09 Apr 2017 20:02:39 +0100 Received: from [127.0.0.1] (localhost [127.0.0.1]) by pn.abelian.org (Postfix) with ESMTP id 303A54005DC for ; Sun, 9 Apr 2017 19:02:38 +0000 (UTC) To: rsgb_lf_group@blacksheep.org References: <15b53e03034-4b3b-c65a@webprd-a62.mail.aol.com> From: Paul Nicholson Message-ID: <995e6f0f-e467-d279-4be6-20d627febe5a@abelian.org> Date: Sun, 9 Apr 2017 19:02:37 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <15b53e03034-4b3b-c65a@webprd-a62.mail.aol.com> X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - porthos.netcom.co.uk X-AntiAbuse: Original Domain - blacksheep.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - abelian.org X-Get-Message-Sender-Via: porthos.netcom.co.uk: authenticated_id: catchall@abelian.org X-Authenticated-Sender: porthos.netcom.co.uk: catchall@abelian.org X-Scan-Signature: fc152e7304849b9a177649b85aea9f41 Subject: Re: VLF: EbNaut tonite Content-Type: text/plain; charset=utf-8; format=flowed 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 2.75 Status: RO X-Status: X-Keywords: X-UID: 11185 Jacek wrote: > we went from joy because we were able to decode a simple carrier > from a high power transmission using a kite antenna, to decoding > multi-character medium-power transmissions with ease. I was thinking just the same thing recently. When you look back, VLF has come a long way in the last seven years. Here is the first sign of an amateur VLF signal received at Todmorden, 15th March 2010, http://abelian.org/vlf/tmp/ss100315a.png It was actually a very strong signal, 20dB stronger than we routinely use today. But at the time it was not entirely certain that this was a genuine signal and not some artifact or interference. That's why the title doesn't mention DK7FC. It took a bit of work to be sure of it. After many years of listening to natural radio at VLF it was quite a novelty to pick up an amateur radio signal! Two things are interesting to note. One is that Stefan's kite experiment could have been done 20 or more years earlier. I don't think we used any technology or knowledge that wasn't available in say 1990, or even 1985. It just needed somebody to go out there and try it. The other thing is that, although the art has been developed greatly since then, I don't think anything new has been invented. We've just pulled in whatever existing technology appears useful. There are no break-through antenna designs or marvelous new DSP algorithms. It makes you wonder what else is out there, just waiting to be tried for the first time. -- Paul Nicholson --