Return-Path: Received: (qmail 3762 invoked from network); 27 Oct 1999 07:38:06 +0100 Received: from unknown (HELO magnet.force9.net) (195.166.128.26) by guiness.force9.net with SMTP; 27 Oct 1999 07:38:06 +0100 Received: (qmail 6077 invoked from network); 27 Oct 1999 06:46:11 -0000 Content-Transfer-Encoding: 8bit Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by magnet.plus.net.uk with SMTP; 27 Oct 1999 06:46:11 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.02 #1) id 11gMN0-0003fS-00 for rsgb_lf_group-outgoing@blacksheep.org; Wed, 27 Oct 1999 07:15:38 +0100 X-Priority: 3 X-MSMail-Priority: Normal Received: from mail.sci.fi ([195.74.0.53] helo=pefletti.saunalahti.fi ident=root) by post.thorcom.com with esmtp (Exim 3.02 #1) id 11gMMz-0003fM-00 for rsgb_lf_group@blacksheep.org; Wed, 27 Oct 1999 07:15:37 +0100 Received: from default (MLXVIII.hdyn.saunalahti.fi [195.197.6.168]) by pefletti.saunalahti.fi (8.9.1/8.9.1) with SMTP id JAA09078 for ; Wed, 27 Oct 1999 09:15:32 +0300 (EET DST) Message-ID: <3.0.6.32.19991027091531.00800510@laatikko.saunalahti.fi> X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Sender: oh2lx@laatikko.saunalahti.fi (Unverified) X-Mailer: QUALCOMM Windows Eudora Light Version 3.0.6 (32) Date: Wed, 27 Oct 1999 09:15:31 +0300 To: rsgb_lf_group@blacksheep.org From: =?iso-8859-1?Q?V=E4in=F6_Lehtoranta?= Subject: LF: EMRP estimations In-reply-to: <006f01bf1ffd$55a92a80$4ff9abc3@default> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Hi folks, This is just a comment. I recently wrote a short story for the Finnish SRAL magazine about Field strength measurements - which we have been doing for over 40 yrs. We have been flight measuring most Finnish NDB/Locator beacons and all Finnish and Swedish DGPS beacons. Most powerful I've ever seen in N. Europe is Tallinn "LK" 386 kHz radiating abt 30 W. Of 105 Finnish NDB /Locators most (Tx=500W) radiate between 8-12 W, some even 15 W, using a 14 m high top loaded monopole. I made some EMRP calculations for OH1TN who is located 152 km from my place. Can hear him daily as ground wave. For 136 kHz sigma I use 0.5 mS/m, for 300 kHz 1 mS/m. Reino's EMRP can be anything between 10 mW and 50 mW. Hope some day we can make some real field measurements. I have at home an old Anritsu Field strength meter but its sensitivity / selectivity is not good enough. Can only estimate that his real Fs is less than 10 dBuV/m. --------------------------------------------------------- GROUND WAVE FIELD-STRENGHT, MILLINGTON METHOD OH1TN -> OH2LX, Ground distance = 152 km FIELD-STRENGTH DB ABOVE 1 MICROVOLT/METER EPS =10.0 SIGMA = .5 mS/m FREQ = 136. kHz POWER = .05 W DIST. (KM) F-S (DBU) 1.0 66.3 2.0 60.2 3.0 56.5 4.0 53.9 5.0 51.9 6.0 50.2 7.0 48.8 8.0 47.5 9.0 46.4 10.0 45.4 30.0 33.9 50.0 27.2 70.0 22.6 90.0 18.8 110.0 15.7 130.0 12.8 150.0 10.2 170.0 7.8 190.0 5.6 210.0 3.5 END OF CIRCUIT ------------------------------------------------------------ ---------------------------------------------------------- V.K.Lehtoranta, OH2LX, POBox 50, FIN-05401 Jokela, Finland ------ Tel: +358-9-4173965 ---- Fax: +358-9-4173961 ------ E-mail: vaiski@dlc.fi - alias: oh2lx@dlc.fi & oh2lx@sral.fi