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 w6GAubPF001111 for ; Mon, 16 Jul 2018 12:56:40 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ff16F-00077P-Bz for rs_out_1@blacksheep.org; Mon, 16 Jul 2018 11:51:27 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ff16C-00077G-0B for rsgb_lf_group@blacksheep.org; Mon, 16 Jul 2018 11:51:24 +0100 Received: from mout01.posteo.de ([185.67.36.65]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.91_59-0488984) (envelope-from ) id 1ff16A-0006SZ-7y for rsgb_lf_group@blacksheep.org; Mon, 16 Jul 2018 11:51:22 +0100 Received: from submission (posteo.de [89.146.220.130]) by mout01.posteo.de (Postfix) with ESMTPS id E7409210F4 for ; Mon, 16 Jul 2018 12:51:20 +0200 (CEST) X-DKIM-Result: Domain=posteo.de Result=Signature OK DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=posteo.de; s=2017; t=1531738280; bh=wz4XtcnkdSHIn+FIu3AsfAcufWui9Pu9VnpYTOOqcTU=; h=Date:From:To:Subject:From; b=P4yp61Liz3e+X3Fi5lp+6aKBnwni5PmSmZOrkhhDtaHzWb5q0fj9Z3f50oi8WFdGb xiFg/SjZ1E5v9R4zEfSFYO1oQF8ao763JxkrCCuqS1Nsd9OEEgx7437oBqs/PLhezq d/DfADmXY2LeOypSFBOZcmswzEjWXLqJaC1oiAF1/B43KBTs3KJoLsLsDqFTPnrMyN kZ9rw/KnQLyFrqirt9H2vsfwg+N6tBIobgJU9HBfSwop6nvOa7YhKuXKnDpFWOQV8B ZKmyL/PaWej93hpX1ByDECBQg7/yh2EijI8cDjQp4SuTXe+z9HaxlkWswnGj4vdWDG fIPC02S7DcARQ== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 41TgFN1Nkkz9rxZ for ; Mon, 16 Jul 2018 12:51:20 +0200 (CEST) Message-ID: <5B4C78A7.1010208@posteo.de> Date: Mon, 16 Jul 2018 12:51:19 +0200 From: DK7FC User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <806f6cb0-fac1-64cc-95b6-0c2c5277f8d8@n1bug.com> In-Reply-To: <806f6cb0-fac1-64cc-95b6-0c2c5277f8d8@n1bug.com> X-Spam-Score: -2.3 (--) 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 @@CONTACT_ADDRESS@@ for details. Content preview: Hi Paul, Am 16.07.2018 12:17, schrieb N1BUG: > I was planning to build a double size K9AY loop (like W1VD uses) but > its 'gain' at 137 kHz models to -55 dBi. It seems to me this puts it > at or below the noise output of the little vertical when moved away > from the Tx antenna. If that is so, then I will never be able to use it! You will need a preamp for this antenna. [...] Content analysis details: (-2.3 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [185.67.36.65 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: e90dcb17768c7e768f13e0721cc1c0c7 Subject: Re: LF: TX > RX isolation test 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=0.0 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 Hi Paul, Am 16.07.2018 12:17, schrieb N1BUG: > I was planning to build a double size K9AY loop (like W1VD uses) but > its 'gain' at 137 kHz models to -55 dBi. It seems to me this puts it > at or below the noise output of the little vertical when moved away > from the Tx antenna. If that is so, then I will never be able to use it! You will need a preamp for this antenna. The advatnage of a separate RX E field antenna is that you don't need a low Z ground. 200 Ohm for example is OK. So you may use a simple ground rod far away from the house, a CLEAN earth! On the other side, for a TX antenna, you want a ground Z as los as possible. It can be a noisy ground, like the mains earth ground system (in parallel with somethig else). But when the TX and RX antennas are coupled together, your noise may rise, lowering the RX performance. Thus it is better to keep the antennas as decoupled as possible and use a preamp (with an internal low pass or even band pass filter) instead. 73, Stefan