Return-Path: Received: (qmail 71 invoked from network); 7 Aug 2002 18:23:14 -0000 Received: from warrior.services.quay.plus.net (212.159.14.227) by mailstore with SMTP; 7 Aug 2002 18:23:14 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: (qmail 16869 invoked from network); 7 Aug 2002 18:22:57 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from post.thorcom.com (193.82.116.70) by warrior.services.quay.plus.net with SMTP; 7 Aug 2002 18:22:56 -0000 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 17cWfW-0004DH-00 for rsgb_lf_group-outgoing@blacksheep.org; Wed, 07 Aug 2002 20:40:30 +0100 Received: from imo-r02.mx.aol.com ([152.163.225.98]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 17cWfV-0004Cm-00 for rsgb_lf_group@blacksheep.org; Wed, 07 Aug 2002 20:40:30 +0100 Received: from DL4YHF@aol.com by imo-r02.mx.aol.com (mail_out_v33.5.) id l.de.2b3811f6 (4254) for ; Wed, 7 Aug 2002 13:48:23 -0400 (EDT) From: DL4YHF@aol.com Message-ID: Date: Wed, 7 Aug 2002 13:48:23 EDT Subject: LF: Reasons for different soundcard sensitivity To: rsgb_lf_group@blacksheep.org MIME-Version: 1.0 Content-Type: text/html; charset=windows-1252 X-Mailer: AOL 6.0 for Windows XP DE sub 50 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Content-transfer-encoding: 8bit Dear Jim and group,

The problem you mentioned (Jason decoding and waterfall sensitivity) may not only be a problem of the soundcard itself. Just a thought:

The reason can also be the computer itself: If windoze (or something else) occupies the CPU for too long, there may be an interrupted stream of input samples, producing a phase jump.
To verify this, feed a clean and stable sine wave from an audio generator into the line input, and observe the signal on the waterfall (either Jason, Argo, SpecLab..). If samples get lost, the spectrum will get "broad" occasionally for a few lines on the waterfall display.

On my office-PC the inevitable microsoft-jingle is chopped into pieces when the system boots, despite a 1GHz-CPU. No trouble on an old 266 MHz-workhorse. I guess the DMA from harddisk and soundcard collide in some cases, in other cases they dont. Or one soundcard has a larger hardware buffer than others. Time to build external ADC hardware.. ?

Different SNR of the soundcards should'nt be the reason, as long at the input level is properly set. Or does one of the tested cards only have an 8-bit ADC ?

Regards,
 Wolf  DL4YHF.