Return-Path: Received: (qmail 54405 invoked from network); 17 Dec 2003 14:43:27 -0000 Received: from unknown (HELO ptb-mxscan03.plus.net) (212.159.14.237) by ptb-mailstore01.plus.net with SMTP; 17 Dec 2003 14:43:27 -0000 Received: (qmail 31551 invoked from network); 17 Dec 2003 14:43:27 -0000 X-Filtered-by: Plusnet (hmail v1.01) X-Priority: 3 X-MSMail-Priority: Normal X-Spam-detection-level: 11 Received: from ptb-mxcore03.plus.net (212.159.14.217) by ptb-mxscan03.plus.net with SMTP; 17 Dec 2003 14:43:27 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore03.plus.net with esmtp (Exim) id 1AWctb-0008CS-CU for dave@picks.force9.co.uk; Wed, 17 Dec 2003 14:43:27 +0000 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1AWcsa-0003Xb-VU for rs_out@blacksheep.org; Wed, 17 Dec 2003 14:42:24 +0000 Received: from [213.218.75.234] (helo=smtp05.freeler.nl) by post.thorcom.com with esmtp (Exim 4.14) id 1AWcsZ-0003XS-NI for rsgb_lf_group@blacksheep.org; Wed, 17 Dec 2003 14:42:23 +0000 Received: (qmail 11165 invoked from network); 17 Dec 2003 14:42:22 -0000 X-Fake-Domain: unknown Received: from unknown (HELO w8k3f0.freeler.nl) ([62.21.138.237]) (envelope-sender ) by smtp05.freeler.nl (qmail-ldap-1.03) with SMTP for ; 17 Dec 2003 14:42:21 -0000 Message-ID: <6.0.1.1.2.20031217142629.03a80840@POP3.freeler.nl> X-Sender: FRE0000086604@POP3.freeler.nl (Unverified) X-Mailer: QUALCOMM Windows Eudora Version 6.0.1.1 Date: Wed, 17 Dec 2003 15:44:18 +0100 To: "LF-Group" From: "Dick Rollema" MIME-Version: 1.0 Subject: LF: Field strength of PA0SE and DCF39 Content-Type: text/html; charset=windows-1252 X-Spam-Checker-Version: SpamAssassin 2.60 (1.212-2003-09-23-exp) on post.thorcom.com X-Spam-Status: No, hits=0.0 required=5.0 tests=HTML_MESSAGE autolearn=no version=2.60 X-SA-Exim-Scanned: Yes Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-PN-SPAMFiltered: yes X-Spam-Rating: 1 Content-transfer-encoding: 8bit To All from PA0SE,

This morning I measured the field strength of my transmitter again, after improving the insulation at the feed-through of the aerial to the shack, using the centre conductor plus insulation of RG-213 coax, surrounded by a paxolin tube through the hard wood window frame.

In the open countryside at 5.83km from the aerial field strength was 610 microvolt/m. From this follows a radiated power of 140mW EMRP.

Transmitter output 300W
Aerial current 3.2A
From this follows:
Total resistance in the aerial-earth system is 300/(3.2 x 3.2) = 29.3 ohm.
Loss resistance in the coil 9.3 ohm.
Earth resistance 29.3 - 9.3 = 20 ohm.

When measuring FS I always measure the FS of DCF39 as well.

This morning I found FS = 1.29mV/m in the countryside. This is remarkably low.
On 12 April 2000 I found 1.93mV/m
On 4 December 2003 it was 2.13mV/m.

But when I measured FS in the afternoon in the shack it was back at 2.13 mV/m again. (On an earlier occasion I have found that FS of DCF39 in the shack does not differ from what I measure in the open country, which is rather remarkable.)
So it seems DCF39 suffered a temporary power reduction this morning.

73, Dick, PA0SE