Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dh02.r1000.mx.aol.com (Internet Inbound) with ESMTP id 0B718380000A4; Tue, 23 Oct 2012 05:06:55 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1TQaQR-0004hp-Ib for rs_out_1@blacksheep.org; Tue, 23 Oct 2012 10:05:27 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1TQaQQ-0004hg-S1 for rsgb_lf_group@blacksheep.org; Tue, 23 Oct 2012 10:05:26 +0100 Received: from out1.ip05ir2.opaltelecom.net ([62.24.128.241]) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1TQaQO-0007dG-9c for rsgb_lf_group@blacksheep.org; Tue, 23 Oct 2012 10:05:25 +0100 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AhQKAHVchlBcHnaQ/2dsb2JhbABEgkqtC5B/A4ELgQmCGQUBAQUIAQEDSQIsAQEDBQIBAxEEAQEKJRQBBBoGFggGEwoBAgIBAYdhAxOsNZBJinhnBYEUhUUDiCWFR4YxgmuKEgOFDYJv X-IronPort-AV: E=Sophos;i="4.80,634,1344207600"; d="scan'208,217";a="397391552" Received: from host-92-30-118-144.as13285.net (HELO xphd97xgq27nyf) ([92.30.118.144]) by out1.ip05ir2.opaltelecom.net with SMTP; 23 Oct 2012 10:05:23 +0100 Message-ID: <000f01cdb0fd$85c495c0$0501a8c0@xphd97xgq27nyf> From: "mal hamilton" To: References: Date: Tue, 23 Oct 2012 09:05:17 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Spam-Score: 4.4 (++++) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Laurence Avoid such problems on LF/MF by using a vertical system like an inv L etc. Loops do not attract me because of the problems associated with high currents as you have stated 65 Amps !! One USA station some time back running QRO was talking about 90 Amps Big resonated loops are great for Receiving in the chosen direction but I leave them alone for Transmitting On the higher frequencies one wave length loops for the desired frequency are a different story. De malg3kev [...] Content analysis details: (4.4 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 SPF_PASS SPF: sender matches SPF record 0.0 HTML_MESSAGE BODY: HTML included in message 4.4 AXB_XMAILER_MIMEOLE_OL_024C2 AXB_XMAILER_MIMEOLE_OL_024C2 X-Scan-Signature: d0d76c369792b807e0925732d18ad9b1 Subject: LF: Re: Heating up Brass question Content-Type: multipart/alternative; boundary="----=_NextPart_000_000C_01CDB0FD.8562C6B0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,HTML_MESSAGE 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 x-aol-global-disposition: G x-aol-sid: 3039ac1d411650865e2f5f02 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. ------=_NextPart_000_000C_01CDB0FD.8562C6B0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Laurence Avoid such problems on LF/MF by using a vertical system like an inv L = etc. Loops do not attract me because of the problems associated with = high currents as you have stated 65 Amps !! One USA station some time = back running QRO was talking about 90 Amps Big resonated loops are great for Receiving in the chosen direction but = I leave them alone for Transmitting On the higher frequencies one wave length loops for the desired = frequency are a different story. De malg3kev =20 ----- Original Message -----=20 From: Laurence KL1 X=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Monday, October 22, 2012 11:09 PM Subject: LF: Heating up Brass question With my tuning unit for my 137 kHz LF amplifier the Ceramic feedthru = fasteners are Brass 1/4 inch diemater - and are getting a little warm. = Brass doesnt have the best low resistance compared with Copper etc. =20 With the Tx running last night full throttle (or close to it) the = total loop current was approaching 65A causing the Bolt(s) to get quite = warm. =20 The feedthrus are seen in the photo going thru the Rubbermaid at the = back - http://kl7uk.com/loop1500.jpg (this is the original tuner - = some of the components have changed for XPQ) =20 There is probably around 2Kv or more inplaces in the tuner and Im = seriously considering running the antennae cable straight thru the tub = wall using apporopiate weather proof grommets and using the plastic = rubbermaid together with the wire insulation into the tuning components = as the dilectric - Im concerned about any heating up of components - = but at this kind of current its more like designing a car alternator or = battery system :-) =20 Any one any pointers or suggestions - Im trying to eliminate any nut = bolt connection as Ohms arent wanted.... =20 Laurence KL 1 X ------=_NextPart_000_000C_01CDB0FD.8562C6B0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Laurence
Avoid such problems on LF/MF by = using a=20 vertical system like an inv L etc. Loops do not attract me because of = the=20 problems associated with high currents as you have stated 65 Amps !! One = USA=20 station some time back running QRO was talking about 90 = Amps
Big resonated loops are great for = Receiving in the=20 chosen direction but I leave them alone for Transmitting
On the higher frequencies one wave = length loops for=20 the desired frequency are a different story.
De malg3kev
 
----- Original Message -----
From:=20 Laurence KL1 X =
Sent: Monday, October 22, 2012 = 11:09=20 PM
Subject: LF: Heating up Brass=20 question


With my tuning unit for my 137 kHz LF = amplifier the=20 Ceramic feedthru fasteners are Brass 1/4 inch diemater - and are = getting=20 a little warm. Brass doesnt have the best low resistance compared with = Copper=20 etc.
 
With the Tx running last night full throttle (or = close to=20 it) the total loop current was approaching 65A causing the Bolt(s) to = get=20 quite warm.
 
The feedthrus are seen in the photo going = thru the=20 Rubbermaid at the back -  http://kl7uk.com/loop1500.jpg&= nbsp; =20 (this is the original tuner - some of the components have changed for=20 XPQ)
 
There is probably around 2Kv or more inplaces in the = tuner=20 and Im seriously considering running the antennae cable straight thru = the tub=20 wall using apporopiate weather proof grommets and using the plastic = rubbermaid=20 together with the wire insulation into the tuning components as the=20 dilectric -  Im concerned about any heating up of components = - but=20 at this kind of current its more like designing a car alternator or = battery=20 system :-)
 
Any one any pointers or suggestions - Im = trying to=20 eliminate any nut bolt connection as Ohms arent=20 wanted....
 
Laurence KL 1 = X
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