Return-Path: Received: (qmail 26369 invoked from network); 13 Dec 2002 16:35:53 -0000 Received: from warrior.services.quay.plus.net (212.159.14.227) by mailstore with SMTP; 13 Dec 2002 16:35:53 -0000 Content-Transfer-Encoding: 8bit Received: (qmail 28708 invoked from network); 13 Dec 2002 16:35:24 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from post.thorcom.com (193.82.116.70) by warrior.services.quay.plus.net with SMTP; 13 Dec 2002 16:35:24 -0000 X-SQ: A X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from majordom by post.thorcom.com with local (Exim 4.10) id 18Msl5-0001Px-00 for rsgb_lf_group-outgoing@blacksheep.org; Fri, 13 Dec 2002 16:33:51 +0000 Received: from [147.197.200.9] (helo=hestia.herts.ac.uk) by post.thorcom.com with esmtp (Exim 4.10) id 18Msl5-0001Po-00 for rsgb_lf_group@blacksheep.org; Fri, 13 Dec 2002 16:33:51 +0000 Received: from gemini ([147.197.200.44] helo=gemini.herts.ac.uk) by hestia.herts.ac.uk with esmtp (Exim 3.22 #1) id 18Mrot-0004Ku-00 for rsgb_lf_group@blacksheep.org; Fri, 13 Dec 2002 15:33:43 +0000 Received: from [147.197.232.252] (helo=rsch-15.herts.ac.uk) by gemini.herts.ac.uk with esmtp (Exim 3.33 #1) id 18Mror-0003Gb-00 for rsgb_lf_group@blacksheep.org; Fri, 13 Dec 2002 15:33:41 +0000 Message-ID: <5.1.0.14.0.20021213150612.029e8c38@gemini.herts.ac.uk> X-Sender: mj9ar@gemini.herts.ac.uk X-Mailer: QUALCOMM Windows Eudora Version 5.1 Date: Fri, 13 Dec 2002 15:33:35 +0000 To: rsgb_lf_group@blacksheep.org From: "James Moritz" In-reply-to: <000d01c2a2af$a32b5de0$09dc9384@jka> References: MIME-Version: 1.0 X-MailScanner: No Virus detected Subject: LF: Re: Jason on 136 Friday night, Argo settings Content-Type: text/plain; charset=us-ascii; format=flowed X-Spam-Status: No, hits=-1.2 required=5.0tests=DEAR_SOMEBODY,IN_REP_TO,QUOTED_EMAIL_TEXT,REFERENCES, SPAM_PHRASE_00_01version=2.42 Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Dear Markus, John, LF Group, At 08:57 13/12/2002 -0500, you wrote: > >- I am usually avoiding the AGC automatic gain setting as it makes it >impossible to distinguish between reduced signal and increased noise. >Sometimes when dashes are disrupted to a pair of dots, it would help to see >whether there is a burst of QRN in the middle.< > >I have used it to make things less touchy with my local noise levels, which >are both considerable and variable If you recall the "Hendrixizer" from some time ago, the same effect works well with QRSS. If you crank the RX gain up until the audio out is heavily clipped, it does quite a good job of reducing the effect of QRN crashes. The other effect is that, because you are effectively limiting the noise amplitude, the output noise level is fairly independent of the actual amplitude of the noise at the input. This makes the display quite tolerant to gradual changes of noise level. Try it - you might be surprised! On my RX, I just switch off the AGC and turn AF and RF gain to maximum, and set the sound card gain so it is well below overload - it sounds horrible, but the vertical streaks largely dissapear. Of course, it will only work if there are no strong signals above the noise within the RX passband; if there are, you will get FM-like quieting, where the strong signal suppresses the noise and weak signals. It won't help much either if there is strong noise drifting rapidly in and out of the passband, but then AGC will be just as bad. I will run a Jason mode beacon on 137.500kHz tonight, over at least 2300 - 0200 utc - any reports will be welcome. Cheers, Jim Moritz 73 de M0BMU