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 w2GCtIUI010354 for ; Fri, 16 Mar 2018 13:55:21 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ewonA-0000E0-Ch for rs_out_1@blacksheep.org; Fri, 16 Mar 2018 12:49:04 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ewon9-0000Dq-TL for rsgb_lf_group@blacksheep.org; Fri, 16 Mar 2018 12:49:03 +0000 Received: from resqmta-ch2-06v.sys.comcast.net ([2001:558:fe21:29:69:252:207:38]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1ewon6-0005lN-QZ for rsgb_lf_group@blacksheep.org; Fri, 16 Mar 2018 12:49:02 +0000 Received: from resomta-ch2-10v.sys.comcast.net ([69.252.207.106]) by resqmta-ch2-06v.sys.comcast.net with ESMTP id womgePDqu91pywon1e5wCW; Fri, 16 Mar 2018 12:48:55 +0000 X-DKIM-Result: Domain=comcast.net Result=Signature OK DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=q20161114; t=1521204535; bh=+6DUUPzhFg+WIXezhg3S7HZKDAOywcLCFbjoQmvyUWk=; h=Received:Received:From:Subject:To:Content-Type:MIME-Version:Date: Message-ID; b=VNRoj9CxDbZXyRGe1/AHRU1CdYpS+ay3HDAM5SU+DWqmSeyt/mh6hvd/vWbfjxMiX LlFuqNWnDGeXInxKe+Ksu9F8xtDxIOJILP0rxXiTwdZQ6WOh2OGN+oEL/WRcCOuc6+ 7qOIKPowz8UbhB+vObd+4Q6KMBhNkG5PpHWIK7mE/2Z/WTcPqcfRMGUO2IRR8fuk3W goM2zvaYaVDYnd/6BzzQHg+Ig4oGLtbmLy0r7RqFd7hwZdnQono7EbmXT0fvmKWS2+ 3oGSTYtxDMwQIiCqt//U07Mn7A4ke5FbKUhTto95TqZitE5j1KLAAAenxsevPINr9j /h9AupUzyhUfw== Received: from Optiplex980-PC ([73.4.253.141]) by resomta-ch2-10v.sys.comcast.net with SMTP id womye3tqfk1NjwomzeyDrn; Fri, 16 Mar 2018 12:48:55 +0000 From: "jrusgrove@comcast.net" To: "rsgb_lf_group@blacksheep.org" MIME-Version: 1.0 References: <772364530.20180316113613@gmail.com> <1521203464226.5324@kuleuven.be> Date: Fri, 16 Mar 2018 08:48:55 -0400 Message-ID: <1UQPmRoah2.2dwZP2sJBsr@optiplex980-pc> In-Reply-To: <1521203464226.5324@kuleuven.be> User-Agent: OEClassic/2.7 (Win7; P; 2017-02-12) X-Mailer: OEClassic/2.7 (Win7; P; 2017-02-12) X-CMAE-Envelope: MS4wfGcl5EjHH7a3UG7o7c4QerqiLljrGSW8eUsGSqfa+mXj9x6qXoLrcgHLxnGb8UKXFtw0MmoOvNiBy7e/sQAmW3JHiIyJa1h6wrJ5IOKyHKiVkVZagsaz oGgvLGnWLVjg9WHH9VosvMysW+tqFtlvPouwTJA+xiLB6U/M/a99rqUmGFCMJ2w7cRVBIoJibabhAQ== 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: Rik Agree ... except one should ideally switch between a 50 ohm load and the antenna when running the test. Jay W1VD [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (jrusgrove[at]comcast.net) -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: 72f3686d3f5e154c987315e88c667a5f Subject: Re: LF: Pre amp *after* BPF?? Content-Type: multipart/alternative; boundary="2SeUDSC9HQu=_vVGpRQqCa7ReFr79jYnDk" 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=HTML_30_40, HTML_FONTCOLOR_UNSAFE,HTML_MESSAGE,TO_ADDRESS_EQ_REAL 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 This is a multi-part message in MIME format --2SeUDSC9HQu=_vVGpRQqCa7ReFr79jYnDk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Rik Agree ... except one should ideally switch between a 50 ohm load and t= he=20 antenna when running the test. Jay W1VD ----- Original Message ----- From: Rik Strobbe Reply-To: To: LineOne Cc: Chris Wilson Sent: 3/16/2018 8:31:03 AM Subject: Re: LF: Pre amp *after* BPF?? Keep in mind that you only need a pre amp if the "antenna noise" is be= low the=20 receiver noise. Most receivers have reduced sensitivity at LF / MF, but the noiselevel= s at=20 these frequencies is high compared to HF. Easy to check: Listen (with connected antenna) on a quiet frequency (o= nly=20 noise, no signal). Next disconnect the antenna. If the noise level dec= reases=20 you do not need a pre amp (in fact a pre amp will only deteriorate the= IMD=20 behavior and thus create more ghost signals). 73, Rik ON7YD - OR7T Van: owner-rsgb_lf_group@blacksheep.org =20 namens Andy Talbot Verzonden: vrijdag 16 maart 2018 12:54 Aan: LineOne CC: Chris Wilson Onderwerp: Re: LF: Pre amp *after* BPF??=20 After, definitely=20 Before is applicable to VHF and up where equipment noise figure domina= tes=20 sensitivity and a filter in the antenna side wold add loss and degrade= overall=20 NF At HF and certainly LF, atmos noise dominates to noise figure is unimp= ortant. =20 That way you get the benefit of rejecting strong OOB signals that may = stress=20 even the preamplifier 'jnt On 16 March 2018 at 11:36, Chris Wilson wrote: Hello LF'ers, Been Googling and see a mixed response to should a receive pre-amp go= before or after a BPF. I have mine before the pre-amp, does the panel= concur with this being correct? Thanks! Aerial, isolation transformer for ground loops, BPF, pre-amp, Red= Pitaya as the LF receiver. -- Best regards, Chris mailto:dead.fets@gmail.com --2SeUDSC9HQu=_vVGpRQqCa7ReFr79jYnDk Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline
Rik
 
Agree ... except one should ideally switch between a 50 ohm load = and the antenna when running the test.
 
Jay W1VD
 
 
----- Original Message -----
From: Rik Strobbe <rik.strobbe@kuleuven.be>
Cc: Chris Wilson <dead.fets@gmail.com>
Sent: 3/16/2018 8:31:03 AM
Subject: Re: LF: Pre amp *after* BPF??

Keep in mind that you only need a pre amp if the "antenna noise" is= below the receiver noise.

Most receivers have reduced sensitivity at LF / MF, but the noisele= vels at these frequencies is high compared to HF.

Easy to check: Listen (with connected antenna) on a quiet frequency= (only noise, no signal). Next disconnect the antenna. If th= e noise level decreases you do not need a pre amp (in fact a pre = amp will only deteriorate the IMD behavior and thus create more ghost = signals).


73, Rik  ON7YD - OR7T


Van: owner-rsgb_lf_gro= up@blacksheep.org <owner-rsgb_lf_group@blacksheep.org> namens An= dy Talbot <andy.g4jnt@gmail.com>
Verzonden: vrijdag 16= maart 2018 12:54
Aan: LineOne
CC: Chris WilsonOnderwerp: Re: LF: Pre amp *after* BPF??=20
 
After, definitely=20

Before is applicable to VHF and up where equipment noise figure d= ominates sensitivity and a filter in the antenna side wold add loss an= d degrade overall NF

At HF and certainly LF, atmos noise dominates to noise figure is = unimportant.   That way you get the benefit of rejecting str= ong OOB signals that may stress even the preamplifier

'jnt


On 16 March 2018 at 11:36, Chris Wilson <= dead.fets@gmail.com> wrote:


Hello  LF'e= rs,

Been  Googling and see a mixed response to should a re= ceive pre-amp go
before  or after a BPF. I have mine before th= e pre-amp, does the panel
concur with this being correct? Thanks!
Aerial,  isolation  transformer  for  ground=   loops, BPF, pre-amp, Red
Pitaya as the LF receiver.

--
Best regards,
 = ;Chris                  &= nbsp;       mailto:dead.fets@gmail.com



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