Return-Path: Received: (qmail 2558 invoked from network); 13 Jun 1999 17:34:57 +0100 Received: from magnet.plus.net.uk (HELO magnet.force9.net) (195.166.128.26) by guiness.force9.net with SMTP; 13 Jun 1999 17:34:57 +0100 Received: (qmail 23329 invoked from network); 13 Jun 1999 16:39:43 -0000 Received: from post.thorcom.com (194.75.130.70) by magnet.plus.net.uk with SMTP; 13 Jun 1999 16:39:43 -0000 Received: from troy.blacksheep.org ([194.75.183.50] ident=root) by post.thorcom.com with esmtp (Exim 2.04 #3) id 10tD9x-0000xx-00; Sun, 13 Jun 1999 17:31:01 +0100 Received: (from root@localhost) by troy.blacksheep.org (8.6.12/8.6.12) id QAA29588 for rsgb_lf_group-outgoing; Sun, 13 Jun 1999 16:31:14 GMT Received: from post.thorcom.com (root@post.unica.co.uk [194.75.183.70]) by troy.blacksheep.org (8.6.12/8.6.12) with ESMTP id QAA29584 for ; Sun, 13 Jun 1999 16:31:12 GMT Received: from cask.force9.net ([195.166.128.29]) by post.thorcom.com with smtp (Exim 2.04 #3) id 10tD9b-0000xt-00 for rsgb_lf_group@blacksheep.org; Sun, 13 Jun 1999 17:30:39 +0100 Received: (qmail 25593 invoked from network); 13 Jun 1999 16:31:20 -0000 Received: from relay3.force9.net (HELO relay2.force9.net) (195.166.128.25) by cask.force9.net with SMTP; 13 Jun 1999 16:31:20 -0000 Received: (qmail 246 invoked from network); 13 Jun 1999 16:24:27 -0000 Received: from 262.hiper02.shef.dialup.force9.net (HELO prstesv1) (195.166.145.6) by relay3.force9.net with SMTP; 13 Jun 1999 16:24:27 -0000 Message-ID: <002201beb5ba$72000120$0600a8c0@prstesv1.prestel.co.uk> From: "Dave" To: rsgb_lf_group@blacksheep.org Subject: LF: Re: Disappearing 'dits' Date: Sun, 13 Jun 1999 17:31:24 +0100 MIME-Version: 1.0 Content-Type: text/html; charset=windows-1252 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 4.72.3110.1 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org Content-transfer-encoding: 8bit

Alan,

I don't think it's the fault of transmitters failing to send proper dots, looking at mine on a scope the envelope is just the same as it would be on HF. I do agree that it's the dots that get lost though, and apart from those stations who don't seem to send any dots, I reckon it's in the receive end of the path. The combination of very narrow RX filters (much narrower than TX antenna/ATU bandwidth) and operation very close to the noise floor means the dots get lost first.

So the moral is "good solid dots" please!

73, Dave G3YXM

Hi After listening to some weak (to me) stations on 136 this morning it occured to me that I was getting a solid, well above the noise dash, but the dits were not at the same peak strength. Noise was fairly low at the time, so it was not being carved up by static. It occurs to me that it may be that some keyers, or even some 'fists', are producing very shorts dots even at the relatively easy speeds used on 136. Can it be that the Q's of aerials and tuning are such that the TX is not rising to full power during a 'dit'?? I find that a bit hard to believe. I do know that when I was learnimg my morse thanks to an old PO Telegraphist up in Liverpool with a G3K call. He used to say that 'you had to send real SOLID dots on old long trans-oceanic cables' otherwise he reckoned they would not get to the other end! I wonder whether this is a lesson for us ...its not so much the slowing down that helps copy on a weak signal so much as the SOLID dot that the slower more deliberate transmission gives. Being basically lazy and not having been an HF morse user I can't express an opinion either way. It would certainly be interesting to know what the tx rise-time (or maybe the aerial current rise-time) actually was with some of your fairly high Q aerials.

Cheers de Alan G3NYK