Return-Path: Received: from mtain-ma02.r1000.mx.aol.com (mtain-ma02.r1000.mx.aol.com [172.29.96.10]) by air-dc07.mail.aol.com (v129.4) with ESMTP id MAILINDC071-86034cb24259292; Sun, 10 Oct 2010 18:46:49 -0400 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-ma02.r1000.mx.aol.com (Internet Inbound) with ESMTP id 268CC38000089; Sun, 10 Oct 2010 18:46:47 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1P54dO-0002LC-3M for rs_out_1@blacksheep.org; Sun, 10 Oct 2010 23:44:50 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1P54dN-0002L3-4q for rsgb_lf_group@blacksheep.org; Sun, 10 Oct 2010 23:44:49 +0100 Received: from nm8-vm0.bullet.mail.ukl.yahoo.com ([217.146.183.238]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1P54dN-0002nI-2X for rsgb_lf_group@blacksheep.org; Sun, 10 Oct 2010 23:44:49 +0100 Received: from [217.146.183.212] by nm8.bullet.mail.ukl.yahoo.com with NNFMP; 10 Oct 2010 22:44:42 -0000 Received: from [217.146.183.171] by tm5.bullet.mail.ukl.yahoo.com with NNFMP; 10 Oct 2010 22:44:41 -0000 Received: from [127.0.0.1] by omp1012.mail.ukl.yahoo.com with NNFMP; 10 Oct 2010 22:44:41 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 312164.34573.bm@omp1012.mail.ukl.yahoo.com Received: (qmail 34133 invoked by uid 60001); 10 Oct 2010 22:44:41 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.co.uk; s=s1024; t=1286750681; bh=5mMD1d9o15NWv186MTK8PQqveEHvFa83I98wjWk6z/M=; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=EJlGReRb0SjZD6Fz+uYJbXQumZSZUIHmEqtsqcjD9k5LVo9v2fzuwI4ua/tAJdwfMsl32Z7dluhnqF8/eP9yf7MQXNPxhz90MYkEtNGSw/oXhjlRi9+/Fw12LJIqBD7dNakFaCb2XyGJaPbsUH0OK1Gq88+CSCoHgHlCwa2P/1U= DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.co.uk; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=Dt6vV80g9I+RkP+Hv2K5M2SNE0Gq/OlpPZDCfXR/sA7MbnjpymZLCyJFhamMaiEIVhyzqZ2lGkH5+l2TqU38MuD2GrsCERn2AxNg/eMTuuMRfwhl9B+xC5PjYhVo6F4Ve5lDJ0X2OKjpJBtGVfzxkGzkjwtq0eDDmTq8/3R95V4=; Message-ID: <166307.34130.qm@web28104.mail.ukl.yahoo.com> X-YMail-OSG: .wpfvMkVM1ltGweEytyaQ1dfOad5QwXaplnRTYS4fezc4Fb 6arQ24xCv__s82WtIkdtQDOeMI2YbURKg6fNJgn54S8FvXJRn2MH6bKOgrEV ENmzcvPrFg16G3F_vPTZZS7b9Cid5euMrrNqEtQNqX1eHJTNEyKYBtGBc2hg EhQVLuiaeynH0OR.0EsWmwdd5R9S3VFKryP_1r3GFyZKY9EgENLhWwzItQrb rT7833lDlGDuqfwEGQGHZXwavRxpJW4cJXPmvmcvhPUJcEqeD3bwiiooU9rz UE7q5Pq3WXQLy Received: from [86.137.113.56] by web28104.mail.ukl.yahoo.com via HTTP; Sun, 10 Oct 2010 23:44:40 BST X-Mailer: YahooMailClassic/11.4.9 YahooMailWebService/0.8.106.282862 Date: Sun, 10 Oct 2010 23:44:40 +0100 (BST) From: M0FMT To: rsgb_lf_group@blacksheep.org In-Reply-To: MIME-Version: 1.0 DomainKey-Status: good (testing) Subject: Re: VLF: Transmit hardware Content-Type: multipart/alternative; boundary="0-1653628994-1286750680=:34130" 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_MESSAGE, HTML_TAG_EXISTS_TBODY 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-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-m279.1 ; domain : yahoo.co.uk DKIM : pass x-aol-sid: 3039ac1d600a4cb2425677e2 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none --0-1653628994-1286750680=:34130 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Hi Markus =A0 Great development work always the unexpected in the best planning. =A0 In UK 405 line TV was notorious for the 10kc/s whistle from the LOPTI (405= x25 [interlaced] frame TB =3D 10125Hz) and even the modern 625 lineTV=A0is= / was noticable at around 15kc/s (kHz) by the younger generation with goo= d ears... ;-)=A0=A0=A0 =A0 So, yes I can understand the issue now you bring it up. =A0 BTW I have been looking with Sound card RX and LW but seem to be getting= odd effects new to me BC AM break thro -=A0also not seeing any Alpha stat= ions? The big Mil stations are visible with a station on 18kc/s transmitti= ng 12wpm CW at times then TTY and other phase shift transmissions..... the= CW always ends with a K as though inviting a reply. =A0 Thanks for your efforts Markus. 73 es GL petefmt I support www.NotSpotTelecom.Com your community Telco / ISP. --- On Sun, 10/10/10, Markus Vester wrote: From: Markus Vester Subject: Re: VLF: Transmit hardware To: rsgb_lf_group@blacksheep.org Date: Sunday, 10 October, 2010, 11:20 I got a complaint from the neighbourhood about acoustic radiation from the= coil! So I=A0interrupted the carrier for a few minutes around 12:35 and= improvised a foam package for noise mitigation. =A0 BTW It is quite remarkable that=A0an air coil vibrates at=A09 kHz and not= 18 kHz, as Lorentz forces between windings should be a purely quadratic= effect. I presume that the vibration is induced by the earth field - at= only 50 uT it's amazing how strong the effect still is! The loudest part= of the setup is the ferrite transformer, probably due to magnetostriction= , with bias from=A0some remanent core magnetisation. =A0 Best wishes for a quiet Sunday, =A0 MArkus (DF6NM) =A0 =A0 ----- Original Message -----=20 From: M0FMT=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Sunday, October 10, 2010 12:02 AM Subject: Re: VLF: Transmit hardware ... XYL has warned no coils on the roof here!............. hee. =20 --0-1653628994-1286750680=:34130 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
=20 --0-1653628994-1286750680=:34130--
Hi Markus
 
Great development work always the unexpected in the best planning.
 
In UK 405 line TV was notorious for the 10kc/s whistle from the LOPTI= (405x25 [interlaced] frame TB =3D 10125Hz) and even the modern 625 lineTV=  is / was noticable at around 15kc/s (kHz) by the younger generation= with good ears... ;-)   
 
So, yes I can understand the issue now you bring it up.
 
BTW I have been looking with Sound card RX and LW but seem to be gett= ing odd effects new to me BC AM break thro - also not seeing any Alph= a stations? The big Mil stations are visible with a station on 18kc/s tran= smitting 12wpm CW at times then TTY and other phase shift transmissions...= .. the CW always ends with a K as though inviting a reply.
 
Thanks for your efforts Markus.

73 es GL petefmt

I supp= ort www.NotSpotTelecom.Com your community Telco / ISP.

--- On Su= n, 10/10/10, Markus Vester <markusvester@aol.com> wrote:<= BR>

From: Markus Vester <markusvester@aol.com&g= t;
Subject: Re: VLF: Transmit hardware
To: rsgb_lf_group@blacksheep.= org
Date: Sunday, 10 October, 2010, 11:20

I got a complaint from the neighbourhood= about acoustic radiation from the coil! So I interrupted the carrier= for a few minutes around 12:35 and improvised a foam package for noise mi= tigation.
 
BTW It is quite remarkable that an= air coil vibrates at 9 kHz and not 18 kHz, as Lorentz forces between= windings should be a purely quadratic effect. I presume that the vibratio= n is induced by the earth field - at only 50 uT it's amazing how strong th= e effect still is! The loudest part of the setup is the ferrite transforme= r, probably due to magnetostriction, with bias from some remanent cor= e magnetisation.
 
Best wishes for a quiet Sunday,
 
MArkus (DF6NM)
 
 
----- Original Message -----
From: M0FMT
Sent: Sunday, October 10, 2010 12:0= 2 AM
Subject: Re: VLF: Transmit hardware=

...
XYL has warned no coils on the roof here!............. hee.