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 vBH7MPV5015929 for ; Sun, 17 Dec 2017 08:22:28 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1eQT5B-0006Hq-1Z for rs_out_1@blacksheep.org; Sun, 17 Dec 2017 07:09:57 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1eQT5A-0006Hh-KD for rsgb_lf_group@blacksheep.org; Sun, 17 Dec 2017 07:09:56 +0000 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 1eQT56-0006kH-Vz for rsgb_lf_group@blacksheep.org; Sun, 17 Dec 2017 07:09:55 +0000 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:References:Reply-To:To:From:Subject:Sender: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=GlbjAwk8AoLPVW3p2/EtJ3q00ThTnzvOwRFM14+Pkk0=; b=CZ4bNdsGK7HPjxvc1YdM/6sbcO 0shXILCi+0S+yj9UvK4jABdCG//hsPhu8HFXqNK5zeHEnNzKc+m+ytz6CJQ2Jbfe/s8c2QF+Lymrv H+jhnlzafniRCUK7T12h77nPZXjOu8iOG0RjTAXYIpRrcJ2t96D2meSsViSJtbtbhJm4=; Received: from i-194-106-52-83.freedom2surf.net ([194.106.52.83]:43968 helo=pn.abelian.org) by porthos.netcom.co.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89_1) (envelope-from ) id 1eQT55-0000to-CT for rsgb_lf_group@blacksheep.org; Sun, 17 Dec 2017 07:09:51 +0000 Received: from [127.0.0.1] (localhost [127.0.0.1]) by pn.abelian.org (Postfix) with ESMTP id 726E24000C1 for ; Sun, 17 Dec 2017 07:09:50 +0000 (UTC) From: Paul Nicholson To: rsgb_lf_group@blacksheep.org References: <4d96a9d4-5f22-7650-872b-6344e9aea8e3@abelian.org> <023201d367cf$8a5761b0$9f062510$@comcast.net> <579355A36AEE9D4FA555C45D556003AB9AAAF572@servigilant.vigilant.local> <2166618d-7238-0516-367c-2f917532eed2@abelian.org> <5A20A4EC.4060009@posteo.de> <5A2694B9.4050407@posteo.de> <21caec0e-1514-3294-89a3-8569f0c6d443@abelian.org> <27BE047B-55C1-45E1-9BD8-575D5EF7179C@hurontel.on.ca> <4c4d7934-b02f-0c9f-e251-4c5a07086bef@abelian.org> <526a4012-19d5-aff0-0745-4b02a3a134e8@abelian.org> <5A2FD635.8080503@posteo.de> <807b7164-c345-9650-0c6b-d813b3304483@abelian.org> <0374401c-a9a5-ba61-89e0-15d5ad016ac8@abelian.org> <36a938b7-9db4-7417-26d6-5b4c4eac900e@abelian.org> <5A35A023.5010707@posteo.de> <1f5204c1-f256-f26e-e6dd-a4edc0c8a443@abelian.org> Message-ID: Date: Sun, 17 Dec 2017 07:09:50 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: <1f5204c1-f256-f26e-e6dd-a4edc0c8a443@abelian.org> Content-Language: en-US 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-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: > What type of isolation transformer are you using? All my receivers use Walters OEP transformers, A262 range which are available from many places. For isolation, A262A6E at the output of the rx's line driver and A262A7E at the house end. [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: 046f068074e745d5c60ca47deee9b503 Subject: Re: LF: RE: Todmorden receiver Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.9 required=5.0 tests=FROM_ENDS_IN_NUMS 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 > What type of isolation transformer are you using? All my receivers use Walters OEP transformers, A262 range which are available from many places. For isolation, A262A6E at the output of the rx's line driver and A262A7E at the house end. The input transformer between loop antenna and LT1028 is an A262A1E. This is most important to match the loop Z to the LT1028 for best noise figure. System noise of the new rx measures 0.088 fT in 1Hz near 8270 Hz, spice model predicted 0.074 fT. The excess noise I saw in the breadboard test has gone. When the dust has settled and final tweaks done, I'll be posting full details of E and H receivers. They are quite simple to build and no rare parts. They are designed for optimum performance with the particular E and H antennas that I'm using - this is very important - you can't mix and match pre-amps and antennas, they have to be designed to work together. Here's the response and noise predictions for the H rx, http://abelian.org/vlf/tmp/171217a.png That's the end-to-end (magnetic flux to soundcard input) model so it include the isolating transformers and cat5 cable. Measurements on the bench are agreeing very well with this. The system noise stays below 0.1 fT from 3kHz right up to 200kHz so I'm hoping it will work well also at 137 kHz. -- Paul Nicholson --