Return-Path: Received: (qmail 745 invoked from network); 16 Sep 2001 02:01:03 -0000 Received: from unknown (HELO murphys-inbound.services.quay.plus.net) (212.159.14.225) by excalibur-qfe1-smtp-plusnet.harl.plus.net with SMTP; 16 Sep 2001 02:01:03 -0000 Received: (qmail 7564 invoked from network); 16 Sep 2001 01:59:52 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys with SMTP; 16 Sep 2001 01:59:52 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.16 #2) id 15iR9H-0003di-00 for rsgb_lf_group-outgoing@blacksheep.org; Sun, 16 Sep 2001 02:55:07 +0100 Received: from [212.95.144.6] (helo=publiconline.co.uk) by post.thorcom.com with smtp (Exim 3.16 #2) id 15iR9G-0003db-00 for rsgb_lf_group@blacksheep.org; Sun, 16 Sep 2001 02:55:06 +0100 Received: (qmail 15103 invoked from network); 16 Sep 2001 01:53:02 -0000 Received: from unknown (HELO default) (213.109.130.248) by 212.95.144.6 with SMTP; 16 Sep 2001 01:53:02 -0000 Message-ID: <032601c13e52$93a6b120$f8826dd5@default> From: "Julian Hardstone" To: rsgb_lf_group@blacksheep.org, lowfer@qth.net, amfmtvdx@qth.net References: <3B96D665.86894C88@netins.net> Subject: LF: Re: Long Wave Broadcasting Date: Sun, 16 Sep 2001 02:53:07 +0100 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 5.00.2014.211 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: Sorry to join this thread rather late - yes, they sound fine, the bandwidth limitation almost invariably being imposed by the receiver, especially single-tuned ferrite rods, a limitation which need not apply to the transceivers with wideband front-ends most amateurs are using now. The percentage b/w does seem impressive, but radio engineers in other disciplines would probably feel underwhelmed - how about VHF broadcast radio or UHF TV, where several Tx channels are combined into one antenna (especially in Wales!)? The important point I want to make is that to think about antenna bandwidth is rather misleading - that bit of wire for LF has as much b/w as you like, but it is the antenna *system*, dominated by the matching network, which has limited b/w. Mike has mentioned the BBC Droitwich Tee antenna, and I recall that this is matched not by a sharply resonant tuning coil, but by cascaded and tapered L-C matching networks (perhaps 3-sections). I suppose this starts to look like a bit of transmission line with tapered impedance, and is easily modelled to show the increased bandwidth. Regards - Julian G3TFR ----- Original Message ----- From: Dr. Tom Gruis To: ; ; Sent: Thursday, September 06, 2001 2:50 AM Subject: LF: Long Wave Broadcasting > Hi from Iowa, USA, EN31do > > This my seem a silly question, but I am curious. > > How is the audio quality of European LW BC stations? The bandwidth > percentage is really something on those frequencies. >