Return-Path: X-Spam-DCC: paranoid 1233; 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,SPF_PASS 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 u3B9Zu1D005654 for ; Mon, 11 Apr 2016 11:35:56 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1apYD5-0002Ek-TK for rs_out_1@blacksheep.org; Mon, 11 Apr 2016 10:32:43 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1apYD5-0002Eb-Kj for rsgb_lf_group@blacksheep.org; Mon, 11 Apr 2016 10:32:43 +0100 Received: from smtpout.karoo.kcom.com ([212.50.160.34]) by relay1.thorcom.net with esmtp (Exim 4.87) (envelope-from ) id 1apYD4-00065x-0P for rsgb_lf_group@blacksheep.org; Mon, 11 Apr 2016 10:32:42 +0100 X-IronPort-AV: E=Sophos;i="5.24,462,1454976000"; d="scan'208";a="159907015" Received: from unknown (HELO [127.0.0.1]) ([109.176.231.201]) by smtpout.karoo.kcom.com with ESMTP; 11 Apr 2016 10:32:40 +0100 Message-ID: <570B6F37.8060402@lineone.net> Date: Mon, 11 Apr 2016 10:32:39 +0100 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: <570A7631.5050001@lineone.net> In-Reply-To: X-Scan-Signature: 4b5b5ebe37a4c4f430f59bc35c1947b0 Subject: Re: LF: Re: Screening an LF Loading Coil Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit 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 10.1.3.11 Status: O X-Status: X-Keywords: X-UID: 7649 Thank you Alan, the location inside makes your suggested spacing, suspended and spaced on fibreglass rods. It needs more Tx testing as a few brief reception reports were about 5dB down but that was probably "propagation" conditions. Hugh. On 10/04/2016 17:04, Alan Melia wrote: > Hi Hugh I think the rule of thumb (or at least the one I use) is that > the lowest turn should be at least half the coil diamter from the > screen base (which if too close will exhibit the properties of a > shorted turn) and the diameter of the screen should be at least twice > the diameter of the coil....more is better, but....... > > I think that should be OK with your coil size supported in the middle > of the keg, Hope you had the pleasure of emptying it :-)) > > Alan > G3NYK > > ----- Original Message ----- From: "LineOne" > To: > Sent: Sunday, April 10, 2016 4:50 PM > Subject: LF: Screening an LF Loading Coil > > >> A few years ago I found an aluminium beer keg which had been used for >> mixing cement. As it was damaged it was no good returning it to the >> brewery so I have just moved my LF loading coil into it and placed >> the assembly outside on a corrugated steel roof. (Having the coil >> suspended from the shack ceiling was not a good idea for the long term). >> >> I took the end off the keg, which is 370mm internal diameter, and the >> coil is on a 130 mm former, likely to be no more than 160mm diameter >> wound. The antenna is predominantly current fed so no voltage larger >> than about 3kV is present. >> >> Has anyone tried this and am I likely to lose radiated power by >> reducing the Q of the coil, the Tx output voltage and current are >> just the same? >> >> Hugh, M0DSZ >> > > >