Return-Path: Received: (qmail 11405 invoked from network); 26 Oct 1999 09:45:20 +0100 Received: from unknown (HELO cask.force9.net) (195.166.128.29) by guiness.force9.net with SMTP; 26 Oct 1999 09:45:20 +0100 Received: (qmail 28261 invoked from network); 26 Oct 1999 08:45:21 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by cask.force9.net with SMTP; 26 Oct 1999 08:45:21 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.02 #1) id 11g1eD-0000Fy-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 26 Oct 1999 09:08:01 +0100 X-Priority: 3 X-MSMail-Priority: Normal Received: from mail2.hamilton-standard.com ([153.4.57.12]) by post.thorcom.com with esmtp (Exim 3.02 #1) id 11g1eC-0000Dr-00 for rsgb_lf_group@blacksheep.org; Tue, 26 Oct 1999 09:08:00 +0100 Received: from curly.hsd.utc.com by mail2.hamilton-standard.com; (8.9.1/) id EAA31759; Tue, 26 Oct 1999 04:15:27 -0400 (EDT) X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from umrsvr.hsd.utc.com by curly.hsd.utc.com; (5.65v3.2/1.1.8.2/27Feb96-0334PM) id AA03677; Tue, 26 Oct 1999 04:06:53 -0400 Received: from nmex01nt.hsd.utc.com by umrsvr.hsd.utc.com; (8.9.0/) id EAA12500; Tue, 26 Oct 1999 04:04:34 -0400 (EDT) Received: by nmex01nt.hsd.utc.com with Internet Mail Service (5.5.2448.0) id ; Tue, 26 Oct 1999 09:59:08 +0100 Message-ID: From: "Soegiono, Gamal" To: rsgb_lf_group@blacksheep.org Subject: LF: Re: Technical details of CFH (137kHz) Date: Tue, 26 Oct 1999 09:59:06 +0100 X-Mailer: Internet Mail Service (5.5.2448.0) Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Content-type: text/plain; charset=windows-1252; format=flowed MIME-Version: 1.0 Content-transfer-encoding: 8bit Many thanks to Alan Melia G3NYK and John VE1FTL for the valuable details on canadian station CFH. Antenna systems designed for the frequency range around 150 kHz, composed of vertical mast 200-360m in height, capacitive toploading, radial system 60 to 120 radials (each having a length which is equal to the mast height) reach a typical over-all system efficiency of no less than 80% and no more than 95%, 90% being the most common design target value (for no compromise implementation). example-1 (Donebach LW BC station on 153 kHz): double 360m mast + cap-top transmitter power = 500 kW (27.99 dBkW) EMRP = 794.3 kW (29 dBkW) antenna efficiency = 88% antenna directivity (**) = 1.805 (2.565 dB) antenna gain (**) = 1.589 (2.01 dB) (**) = relative to lossless monopole over perfect ground plane In compromise implementations and for lower operating frequencies, system efficiency degrade rapidly. example-2 (Mainflingen standard time and frequency station on 77.5 kHz): single 200m mast + cap-top transmitter power = 50 kW (17.99 dBkW) EMRP = 30 kW (14.77 dBkW) antenna efficiency = 60% antenna directivity (**) = 1 (0 dB) antenna gain (**) = 0.6 (-2.218 dB) Best 73 de Gamal Gamal Soegiono (SWL) 50N01 / 08E27 / JO 40 fa soegiono@nm.hsd.utc.com or soegiono@nmex01nt.hsd.utc.com