Return-Path: Received: (qmail 7004 invoked from network); 6 Dec 2000 20:32:57 -0000 Received: from unknown (HELO warrior-inbound.servers.plus.net) (212.159.14.227) by extortion.plus.net with SMTP; 6 Dec 2000 20:32:57 -0000 Received: (qmail 1581 invoked from network); 6 Dec 2000 20:35:03 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by warrior with SMTP; 6 Dec 2000 20:35:03 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.16 #1) id 143lAu-0006dC-00 for rsgb_lf_group-outgoing@blacksheep.org; Wed, 06 Dec 2000 20:28:24 +0000 Received: from mail6.svr.pol.co.uk ([195.92.193.212]) by post.thorcom.com with esmtp (Exim 3.16 #1) id 143lAs-0006d5-00 for rsgb_lf_group@blacksheep.org; Wed, 06 Dec 2000 20:28:22 +0000 Received: from modem-200.aluminum.dialup.pol.co.uk ([62.136.12.200] helo=default) by mail6.svr.pol.co.uk with smtp (Exim 3.13 #0) id 143lAm-0001DN-00 for rsgb_lf_group@blacksheep.org; Wed, 06 Dec 2000 20:28:17 +0000 Message-ID: <001301c05fc2$6015a7e0$c80c883e@default> From: "MAL HAMILTON" To: rsgb_lf_group@blacksheep.org Subject: LF: Re: Re: Coils and amplifiers Date: Wed, 6 Dec 2000 19:00:10 -0000 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 4.72.3110.5 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: -----Original Message----- From: Peter Dodd To: rsgb_lf_group@blacksheep.org Date: 06 December 2000 16:09 Subject: LF: Re: Coils and amplifiers >Andy said: > >> Some of us don't have such large antennas as you, Peter. For 1 Watt ERP >> I would need approx 4kW RF. > >Yes, I am well aware of that - and that is why I mentioned I5TGC's LF >antenna, which must be the smallest of the LF antennas in the LF group. >However, the subject was loading coil cooling - and was it necessary. >I only quoted my transmitter power and antenna current because that >was the only experience I had of using higher power at LF > >While on the subject of power amplifiers the only successful design >that I have seen is the one by G3LNP, see 'The LF Experimenter's >Source Book', second edition. You must have missed MM0ALM signal. He is the strongest on the band and uses a tube amplifier designed and built by himself. He is several S points above anyone else. Considering he has no connection with electronics as a profession he could show most others the way. Seem to remember EI0CF with his home designed/built amplifier being the strongest on the band also. Surprised you missed hearing these two stations. Too many early nights or day time doozing off !!!!!!!!!!!!!!!!!!!! G3KEV >I have seen solid state amplifiers that use many separate amplifiers >with the outputs combined using a ferrite transformer. This might be >the way to go in the construction of a less lethal design. >The Decca transmitters were designed with safety (and reliability) in mind. > > > > >-- >Regards, Peter, G3LDO > > > > >