Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id w13HeRkk007481 for ; Sat, 3 Feb 2018 18:40:30 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ei1j8-0007M7-Jh for rs_out_1@blacksheep.org; Sat, 03 Feb 2018 17:35:46 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ei1j1-0007Ly-Ef for rsgb_lf_group@blacksheep.org; Sat, 03 Feb 2018 17:35:39 +0000 Received: from lethe.lipkowski.org ([151.80.54.59] helo=lipkowski.org) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1ei1iy-0007pV-Ji for rsgb_lf_group@blacksheep.org; Sat, 03 Feb 2018 17:35:38 +0000 Received: from mailn.lipkowski.org (localhost [127.0.0.1]) by lipkowski.org (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id w13HcFtv002878 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT) for ; Sat, 3 Feb 2018 18:38:16 +0100 Received: from localhost (sq5bpf@localhost) by mailn.lipkowski.org (8.14.4/8.14.4/Submit) with ESMTP id w13HcE6n002874 for ; Sat, 3 Feb 2018 18:38:14 +0100 X-Authentication-Warning: mailn.lipkowski.org: sq5bpf owned process doing -bs Date: Sat, 3 Feb 2018 18:38:13 +0100 (CET) From: Jacek Lipkowski To: rsgb_lf_group@blacksheep.org In-Reply-To: <5A75EA08.9090009@posteo.de> Message-ID: References: <579355A36AEE9D4FA555C45D556003AB9AB485D3@servigilant.vigilant.local> <5A7377F7.4050802@posteo.de> <017101d39bab$2f0e3710$8d2aa530$@comcast.net> <23159F1ED5BD49AD9654CE5685AFACF6@Clemens0811> <5A75EA08.9090009@posteo.de> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 X-Spam-Score-sq5bpf: -2.9 () ALL_TRUSTED,BAYES_00 X-Scanned-By: MIMEDefang 2.75 on 10.1.3.10 X-Spam-Score: -0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: We did a loop tx experiment with Marcin SQ2BXI on 20 january 2018. The tx was a semi-horizontal 1-turn loop about 150x50m (from memory), 1A current at 8270Hz. The tx frequency was generated via Paul's ebsynth, and locked to GPS. [...] Content analysis details: (-0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain X-Scan-Signature: 7001055fa59a9c23b9831ea6d317a074 Subject: Re: LF: VLF Small magnetic antenna for Tx Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.63 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 We did a loop tx experiment with Marcin SQ2BXI on 20 january 2018. The tx was a semi-horizontal 1-turn loop about 150x50m (from memory), 1A current at 8270Hz. The tx frequency was generated via Paul's ebsynth, and locked to GPS. The signal was detectable 2km away in the H-field, don't remember the exact parameters, but we were using Spectrum Lab and no decimation, so either 366mHz, 183mHz, or 91mHz bins (i think Marcin has this data, including waterfall plots etc). The signal was not detectable in the E-field almost 1/4 wavelength away (abt 7-8km) in my RX site (GPS locked) when i analysed a 1 hour recording. Theoretically after 1/4 wavelength we should see an E-field component if there was any far-field radiation. This is the reason we haven't published anything about it so far (but we will when we get some free time). I've also tried tx experiments years ago with vertical loops: 3 turns 1.5x2.5m on my balcony (detectable at about 500m from the loop), and 1-turn about 2x20m (detectable at about 800m). This was a long time ago, so now i would probably add 20% distance just by using better dsp settings, but still nothing that spectacular. When you're 100m from the coil the signal is very strong, but diminishes with distance quicky. If you want some semi-DX in the H-field, then try coupling into some long conductors (pipes, power lines, railway tracks etc). VY 73 Jacek / SQ5BPF