Return-Path: Received: (qmail 23420 invoked from network); 17 Apr 2001 10:03:41 -0000 Received: from unknown (HELO warrior-inbound.servers.plus.net) (212.159.14.227) by 10.226.25.101 with SMTP; 17 Apr 2001 10:03:41 -0000 Received: (qmail 11024 invoked from network); 17 Apr 2001 10:03:23 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by warrior with SMTP; 17 Apr 2001 10:03:23 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from majordom by post.thorcom.com with local (Exim 3.16 #2) id 14pS9V-0001m4-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 17 Apr 2001 10:52:05 +0100 Received: from mail.sitestar.net ([205.160.234.10] helo=mail.neocom.net) by post.thorcom.com with esmtp (Exim 3.16 #2) id 14pS9N-0001ly-00 for rsgb_lf_group@blacksheep.org; Tue, 17 Apr 2001 10:51:58 +0100 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from sitestar.net (reston-gnap-ip-216013-196.dynamic.ziplink.net [216.8.13.196]) by mail.neocom.net (8.11.2/8.11.2) with ESMTP id f3H9pLn13726 for ; Tue, 17 Apr 2001 05:51:21 -0400 Message-ID: <3ADC1315.2AAC5123@sitestar.net> Date: Tue, 17 Apr 2001 05:55:33 -0400 From: "Rye Gewalt" X-Mailer: Mozilla 4.75 [en] (Win95; U) X-Accept-Language: en MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org Subject: Re: LF: DFCW, an idea. References: <001001c0c64c$3aed0580$bc31893e@g3aqc> Content-Type: text/html; charset=windows-1252 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Content-transfer-encoding: 8bit Great Idea, I have been thinking along the same lines.  There are programs that allow the PC clock to be set within about a second to National Standards using the internet.  The PC clock could be set at the start of a transmission and then there could be a window within the bauds to do the FFT(s)  --- drop a couple of seconds on each end of the baud.  I am a great fan of signal averaging.

I'll try to find the software for synchronizing the PC clock with our Naval Observatory and send you a link.  It's pretty nice and even tells how far your clock was off prior to calibration.  There is some magic I don't understand about the network delays, but apparently they have that pretty well solved.

Regards
Rye

Laurie Mayhead wrote:

Hi all,I am very keen on exploiting DFCW to its limit (after all its easy to implement) but it still needs to be speeded up. Because of the lack of timing of the FFT bins they tend to become blurred and it is neccessary to leave large gaps between elements of a character with consequent waste of time.This is even more true with QRSS. With DFCW the frequency change between dots and dashes adequately separates them. Currently on T/A tests I have been using a 50 sec. period, 30 secs constitutes the transmitted element and 20 secs the gap ! What a waste of time. Looking at the signal on my monitor (also see Uwe's pics,thanks Uwe) these gaps are still poorly defined. I have thought about synchronising the Tx and Rx using some form of universal time signal but 1) this might be thought as cheatingand 2) the path variations, phase changes etc would be a problem. So my point is WHY BOTHER ! would it not still be possible to read the message without these gaps (they are hardly there anyway). For A to Z there is not much of a problem since there are only two adjacent elements ie 2 dots or two dashes, except for JO S H .But the numbers are a bigger problem. Anyway, crazy perhaps but any ideas ?   73s Laurie.