Return-Path: Received: (qmail 2967 invoked from network); 6 Nov 2001 06:46:36 -0000 Received: from unknown (HELO murphys-inbound.services.quay.plus.net) (212.159.14.225) by excalibur.plus.net with SMTP; 6 Nov 2001 06:46:36 -0000 Received: (qmail 356 invoked from network); 6 Nov 2001 06:46:20 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys.services.quay.plus.net with SMTP; 6 Nov 2001 06:46:20 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 160zqN-0003qF-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 06 Nov 2001 06:36:19 +0000 Received: from mta1-rme.xtra.co.nz ([210.86.15.129]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 160zqL-0003q9-00 for rsgb_lf_group@blacksheep.org; Tue, 06 Nov 2001 06:36:17 +0000 Received: from xtr743187 ([210.54.76.179]) by mta1-rme.xtra.co.nz with SMTP id <20011106063453.NRQF3964.mta1-rme.xtra.co.nz@xtr743187> for ; Tue, 6 Nov 2001 19:34:53 +1300 Message-ID: <005201c1668d$7df95a40$b34c36d2@xtr743187> From: "Vernall" To: rsgb_lf_group@blacksheep.org References: <20011105.160737.-484705.3.riese-k3djc@juno.com> Subject: Re: LF: Re: spectrum 136kHz Date: Tue, 6 Nov 2001 19:35:45 +1300 MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.2919.6600 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Hi all, Thanks to Bob Reise for pointing out that ringing voltage is a lot higher than S9. A high pass filter would be a useful precaution for connecting to a telephone line. For checking LF harmonic content it should be connected to an LF receiver, not directly to a sound card. Further, the higher frequency content may propagate in unbalanced mode, rather than in "pushpull", in which case radio sampling could be via a low value capacitor, to either leg of the telephone line. But the practical result is still there, that amateurs should avoid multiples of 8 kHz for weak signal LF DX work. 73, Bob ZL2CA