Return-Path: X-Spam-DCC: paranoid 1170; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-0.7 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, RATWARE_GECKO_BUILD autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id tA4A5lvb026681 for ; Wed, 4 Nov 2015 11:05:47 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ZtuoZ-0004Kf-P7 for rs_out_1@blacksheep.org; Wed, 04 Nov 2015 09:57:11 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ZtuoZ-0004KW-5a for rsgb_lf_group@blacksheep.org; Wed, 04 Nov 2015 09:57:11 +0000 Received: from smtpout.karoo.kcom.com ([212.50.160.34]) by relay1.thorcom.net with esmtp (Exim 4.86) (envelope-from ) id 1ZtunV-0007yN-00 for rsgb_lf_group@blacksheep.org; Wed, 04 Nov 2015 09:57:09 +0000 X-IronPort-AV: E=Sophos;i="5.20,242,1444690800"; d="scan'208";a="138720366" Received: from unknown (HELO [127.0.0.1]) ([109.176.219.98]) by smtpout.karoo.kcom.com with ESMTP; 04 Nov 2015 09:55:52 +0000 Message-ID: <5639D627.5040208@lineone.net> Date: Wed, 04 Nov 2015 09:55:51 +0000 From: LineOne User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:31.0) Gecko/20100101 Thunderbird/31.1.2 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <56390E67.9080708@lineone.net> <3FFB89E1-17BC-4B86-AB26-E5138635FD3A@gmail.com> In-Reply-To: <3FFB89E1-17BC-4B86-AB26-E5138635FD3A@gmail.com> X-Scan-Signature: f62c7cf8eeb8e5a327b71719e9bffff1 Subject: Re: LF: Ferrite Rods For LF Preamplifiers Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit 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 X-Scanned-By: MIMEDefang 2.56 on 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 4813 Thank you, I've saved that, Hugh. On 03/11/2015 20:08, John Rabson wrote: > I haven’t looked at this sort of configuration recently, but it is worth perhaps consulting the doctoral thesis of David Gibson, which you can find at http://etheses.whiterose.ac.uk/4169/1/uk_bl_ethos_270894.pdf > > Chapter 4 contains discussion of antennas, both in air-cored and ferrite-based. Although it principally deals with subterranean situations you may find it useful. > > John F5VLF G3PAI > >> On 03 Nov 2015, at 20:43, LineOne wrote: >> >> Amongst some ferrite rods, I have 3 identical, all with LW & MW windings. I could remove the windings and make a fat bundle of the 3 then wind another coil for an LF preamplifier to improve on my existing one. Inductors are better not to be long and thin I know but what about the magnetic cores such as ferrite? >> This makes some sense, but I would rather join the rods in line, retaining a litz wire LW winding which will tune with about 470pF, ending up with an 18mm PVC tube of about 600mm and a small ABS box in the centre so the whole looks like a VHF dipole. >> Has anyone done this? >> >> Yesterday we were enveloped in a very wet, dripping fog and it seemed to attenuate my few LF transmissions as nobody received them. UHF TV disappeared later in the evening too. >> The antenna is surrounded by about 100 trees which probably doesn't help. GW4NOS was on, in S. Wales I think they had a nice, sunny day and G3XIZ also. >> >> Hugh, M0DSZ >> > john.rabson07@gmail.com > > Researching history of RABSON, BLACKSHAW, GAUNTLETT, VERLANDER and ROBSONNE > > > > > >