Return-Path: Received: (qmail 9211 invoked from network); 31 Jul 2002 16:02:10 -0000 Received: from marstons.services.quay.plus.net (212.159.14.223) by mailstore with SMTP; 31 Jul 2002 16:02:10 -0000 Received: (qmail 29704 invoked by uid 10001); 31 Jul 2002 16:06:59 -0000 Received: from post.thorcom.com (193.82.116.70) by marstons.services.quay.plus.net with SMTP; 31 Jul 2002 16:06:59 -0000 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 17ZxaX-0002ed-00 for rsgb_lf_group-outgoing@blacksheep.org; Wed, 31 Jul 2002 18:48:45 +0100 Received: from darius.concentric.net ([207.155.198.79]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 17ZxaW-0002eY-00 for rsgb_lf_group@blacksheep.org; Wed, 31 Jul 2002 18:48:44 +0100 Received: from newman.concentric.net (newman.concentric.net [207.155.198.71]) by darius.concentric.net [Concentric SMTP Routing 1.0] id g6VFvA227865 for ; Wed, 31 Jul 2002 11:57:13 -0400 (EDT) Received: from jka ([208.37.242.34]) by newman.concentric.net (8.9.1a) id LAA21601; Wed, 31 Jul 2002 11:57:09 -0400 (EDT) Message-ID: <002601c238ac$2dc7e2c0$09dc9384@jka> From: "John Andrews" To: rsgb_lf_group@blacksheep.org References: <7D653C9C42F5D411A27C00508BF8803DCB9B57@mail.dstl.gov.uk> Subject: LF: Re: Droitwich carrier Date: Wed, 31 Jul 2002 12:06:05 -0400 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 6.00.2600.0000 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: > A 'perfect' 100% modulated AM transmission carrying a sinewave should have > 4.8 dB peak to mean, so what mechanism can account for 6.9dB ? This > certainly does seem to reinforce the idea that the carrier reduces with > amplitude. Here in the U.S., positive peak levels of 125% are allowed. The maximum negative peak level is obviously 100%, the point at which the carrier goes away. Not sure what the regulations are over there, but the asymmetry might explain the readings. And I'll echo some earlier comments, here. I used to be in charge of a 5 kW PDM rig that had very little carrier shift with "old fashioned" audio processing ahead of it. But with an Optimod, it used to buck quite a bit. No amount of twiddling with the tilt or other settings on the Optimod would get rid of it. John Andrews, W1TAG