Return-Path: Received: (qmail 21046 invoked from network); 27 Nov 2001 23:08:38 -0000 Received: from unknown (HELO murphys-inbound.services.quay.plus.net) (212.159.14.225) by excalibur.plus.net with SMTP; 27 Nov 2001 23:08:38 -0000 Received: (qmail 13416 invoked from network); 27 Nov 2001 23:08:48 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys.services.quay.plus.net with SMTP; 27 Nov 2001 23:08:48 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 168rIh-0005JI-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 27 Nov 2001 23:06:03 +0000 Received: from tvout.mail.uk.easynet.net ([194.6.96.5]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 168rIe-0005J9-00 for rsgb_lf_group@blacksheep.org; Tue, 27 Nov 2001 23:06:01 +0000 Received: from ericadodd (tnt-18-138.easynet.co.uk [212.134.224.138]) by tvout.mail.uk.easynet.net (Postfix) with SMTP id 5864263452 for ; Tue, 27 Nov 2001 23:05:17 +0000 (GMT) Message-ID: <002101c17798$67ab52e0$8ae086d4@ericadodd> From: "g3ldo" To: rsgb_lf_group@blacksheep.org References: <000901c176df$d74fcb80$0200a8c0@charter.net> <000d01c176e8$24500a00$0300a8c0@charter.net> Subject: LF: Re: 73 kHz Signal Measurements Date: Tue, 27 Nov 2001 23:07:23 -0000 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 5.50.4522.1200 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 John > Of course, there's a lot to be gained by narrowing the BW, so I ran ARGO at > 60 sec/dot, and had to crank in another 13 dB to kill HBG. There's a > considerable time lag in making such measurements, so fading sets some > limits on accuracy. But I did end up barely being able to see the signal > at -77 dB. Interesting, eh? Very interesting indeed. Your method is quite a standard method of making level measurements if the meter on the receiver is not accurate and I can see no fault in it. > > One possible objection to the method is that the absolute value of the > attenuation is probably in error due to the output impedance of the preamp > and the input impedance of the receiver not being 50 ohms. While that's > true, at least the changes in attenuation needed to kill the signal under > various band conditions would still be valid. This will enable me to track > things on a day-to-day basis. > You need some S/W that can record signal level ( I think some has already been suggested) so that it can be left unattended once the attenuation level had been established. I have heard that CFH may also be on, or near, 73.3kHz. Are you able to confirm that it is really Rugby that you are hearing? I guess that with your directional loop antenna you will have that question already resolved. Once you have some data it can be compared with Alan's propagation info to see if anything of interest emerges. Regards, Peter, G3LDO e-mail Web