Return-Path: Received: (qmail 5461 invoked from network); 28 Apr 2003 04:06:48 -0000 Received: from warrior.services.quay.plus.net (212.159.14.227) by mailstore with SMTP; 28 Apr 2003 04:06:48 -0000 Content-Transfer-Encoding: 8bit Received: (qmail 1370 invoked from network); 28 Apr 2003 04:06:40 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from post.thorcom.com (193.82.116.70) by warrior.services.quay.plus.net with SMTP; 28 Apr 2003 04:06:40 -0000 X-SQ: A X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 199zqX-0003xF-Gd for rsgb_lf_group-outgoing@blacksheep.org; Mon, 28 Apr 2003 05:02:29 +0100 Received: from [212.125.75.12] (helo=mail4.messagelabs.com) by post.thorcom.com with smtp (Exim 4.14) id 199zqS-0003x6-LR for rsgb_lf_group@blacksheep.org; Mon, 28 Apr 2003 05:02:24 +0100 X-VirusChecked: Checked X-Env-Sender: William.Ashlock@bocedwards.com X-Msg-Ref: server-23.tower-4.messagelabs.com!1051502542!3058 Received: (qmail 905 invoked from network); 28 Apr 2003 04:02:22 -0000 Received: from ukfw1.ge.boc.com (193.131.2.157) by server-23.tower-4.messagelabs.com with SMTP; 28 Apr 2003 04:02:22 -0000 Received: from ([160.100.160.136]) by ukfw1.ge.boc.com; Mon, 28 Apr 2003 05:03:24 +0100 (BST) Received: from exc_wil04.edwards.boc.com ([162.118.144.226]) by exc_cra03.edwards.boc.com with SMTP (Microsoft Exchange Internet Mail Service Version 5.5.2653.13) id J31XBZ04; Mon, 28 Apr 2003 05:07:21 +0100 Received: by EXC_WIL04 with Internet Mail Service (5.5.2653.19) id <2RDJSZK6>; Mon, 28 Apr 2003 00:03:07 -0400 Message-ID: From: "Ashlock,William" To: rsgb_lf_group@blacksheep.org Date: Mon, 28 Apr 2003 00:03:05 -0400 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2653.19) Subject: LF: RE: Re: RX-LOOP Content-Type: text/plain; charset=iso-8859-1; format=flowed X-Spam-Status: No, hits=0.0 required=5.0tests=noneversion=2.53 X-Spam-Checker-Version: SpamAssassin 2.53 (1.174.2.15-2003-03-30-exp) X-SA-Exim-Scanned: Yes Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rsgb_lf_group-outgoing@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false Alan, all: >I suspect that you need to isolate the loop feed with a small transformer. It is possible that >the feed from the loop is acting as a wire aerial and is conducting TV RFI and noises from the >house *back to the loop*. Surprising how few understand the concept of the RFI actually going from the receiver back to the antenna site. This applies to E-probe antennas as well. The typical house/apartment is a mad jumble of LF RFI having both E and H field components. The proper RF return for remote LF antennas is the ground immediately under the antenna - not the safety (green wire) ground in the shack that connects to the chassis of the receiver. The isolation transformer installed in the coax lead-in offers the only way to sever these totally different grounds. In severe cases one is needed both at the receiver and at the antenna since a floating coax shield can pick up noise before it leaves the vicinity of the shack. BTW, an isolation transformed can be as simple as two 15-turn windings of #22 to #28 wire on a common 3/4"dia X 1" ferrite RFI bead found on computer power cords, monitor cables, communications cables, etc. Bill A _____________________________________________________________________ This e-mail has been scanned for viruses by the WorldCom Internet Managed Scanning Service - powered by MessageLabs. For further information visit http://www.worldcom.com