Return-Path: Received: from mtain-dg07.r1000.mx.aol.com (mtain-dg07.r1000.mx.aol.com [172.29.65.15]) by air-di03.mail.aol.com (v129.4) with ESMTP id MAILINDI034-eac14c41f11315d; Sat, 17 Jul 2010 14:06:11 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dg07.r1000.mx.aol.com (Internet Inbound) with ESMTP id 0AC613800008D; Sat, 17 Jul 2010 14:06:09 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OaBlL-0006wN-1W for rs_out_1@blacksheep.org; Sat, 17 Jul 2010 19:05:23 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OaBlK-0006wE-JB for rsgb_lf_group@blacksheep.org; Sat, 17 Jul 2010 19:05:22 +0100 Received: from mail-bw0-f43.google.com ([209.85.214.43]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1OaBlI-0006T6-RQ for rsgb_lf_group@blacksheep.org; Sat, 17 Jul 2010 19:05:22 +0100 Received: by bwz13 with SMTP id 13so2082877bwz.16 for ; Sat, 17 Jul 2010 11:05:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:content-type; bh=k4NPy+IZfIXdhNjR3C/gVaVVMqfDHOIYc1C+CbHAs9Y=; b=KDPfk8BCl0ZX7VAEsIcyN0+utbpPkU1t0IIaR8Zv4yZkm9BZws7QPEINDDPhqmEzB+ SjSWHb6eiyZbVA3I63H/XwFZ7U77HM2qlFMRAMaD4y723adVInkaRdiqio50iAKIl9DP VVhENCr3bisebLkUyC6c9DujeKhOCxTDwwxig= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=l9csEAxa+IhmbZeOo8+9D7+FLgBggS4fuqv0JIEYGCVAigS6FpwQnF64YRtaYC8I0i 4IzYaqQeVLuYs2Xx+2Q8jpxxu0wiTHQvjQ1w2FlQRkOGN1Q57HQloZn9UonmNWUN7y6s wtad2sgn2+OA8lPe9BQ4dyaDoseMjJyxaRUeo= MIME-Version: 1.0 Received: by 10.204.175.74 with SMTP id w10mr2150098bkz.4.1279389920107; Sat, 17 Jul 2010 11:05:20 -0700 (PDT) Received: by 10.204.122.148 with HTTP; Sat, 17 Jul 2010 11:05:20 -0700 (PDT) In-Reply-To: <4C41EA33.4010002@iup.uni-heidelberg.de> References: <6F39497B262549EABA3A1EF7B433C453@IBM7FFA209F07C> <001301cb2597$b8343630$0401a8c0@xphd97xgq27nyf> <4C41EA33.4010002@iup.uni-heidelberg.de> Date: Sat, 17 Jul 2010 19:05:20 +0100 Message-ID: From: Roger Lapthorn To: rsgb_lf_group@blacksheep.org DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: VLF: 838 Hz Content-Type: multipart/alternative; boundary=00032555834ab79d52048b992d55 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=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-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-d244.1 ; domain : gmail.com DKIM : pass x-aol-sid: 3039ac1d410f4c41f11172fb X-AOL-IP: 193.82.116.20 X-AOL-SPF: domain : blacksheep.org SPF : none X-Mailer: Unknown (No Version) --00032555834ab79d52048b992d55 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi Stefan, The choice of frequency is simply because this is the sidetone frequency from my K1EL keyer IC that I use to generate the QRSS3 and 10wpm CW signal= . It is quite stable too and perfectly suitable for 1-2 hours experimenting within 10km of home. The sidetone is low pass filtered and fed with some attenuation into my TDA2002 audio amp IC. The frequency misses 50Hz harmonics, but these have not been a major issue with my RX preamp which= has 2 cascaded Sallen-Key HPF sections to reject 50Hz and its early harmonics. 73s Roger G3XBM 2010/7/17 Stefan Sch=E4fer > Hi Roger, > > I have just read about your todays ELF TX test on 838 Hz. Congrats! > > Can you tell me why just exactly 838 Hz? Far away from 850 Hz and 800 Hz= , > clear, but why 838? Is there a reason? > > 73 and go on! > > Today i had to cancel my antenna improvement work due to rain and > thunderstorms in the morning but never mind... > > Stefan/DK7FC > > --=20 http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/g3xbm G3XBM GQRP 1678 ISWL G11088 --00032555834ab79d52048b992d55 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi Stefan,

The choice of frequency is simply because this is the si= detone frequency from my K1EL keyer IC that I use to generate the QRSS3 an= d 10wpm CW signal. It is quite stable too and perfectly suitable for 1-2= hours experimenting within 10km of home. The sidetone is low pass filtere= d and fed with some attenuation into my TDA2002 audio amp IC. The frequenc= y misses 50Hz harmonics, but these have not been a major issue with my RX= preamp which has 2 cascaded Sallen-Key HPF sections to reject 50Hz and it= s early harmonics.

73s
Roger G3XBM

2010/7/17 Stefan= Sch=E4fer <schaefer@iup.uni-heidelberg.de>
Hi Roger,

I have just read about your todays ELF TX test on 838 Hz. Congrats!

Can you tell me why just exactly 838 Hz? Far away from 850 Hz and 800 Hz,= clear, but why 838? Is there a reason?

73 and go on!

Today i had to cancel my antenna improvement work due to rain and thunders= torms in the morning but never mind...

Stefan/DK7FC




--
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/g3xbm
G3XBM=A0 =A0 GQRP 1678=A0 =A0 =A0 ISWL G11088
--00032555834ab79d52048b992d55--