Return-Path: <majordom@post.thorcom.com> Received: (qmail 26995 invoked from network); 26 Jul 1999 16:35:34 +0100 Received: from magnus.plus.net.uk (HELO magnus.force9.net) (195.166.128.27) by guiness.force9.net with SMTP; 26 Jul 1999 16:35:34 +0100 Received: (qmail 306 invoked from network); 26 Jul 1999 15:38:08 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by magnus.plus.net.uk with SMTP; 26 Jul 1999 15:38:08 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.02 #1) id 118mOt-00000m-00 for rsgb_lf_group-outgoing@blacksheep.org; Mon, 26 Jul 1999 16:10:47 +0100 Received: from [143.179.236.32] (helo=Lesothosaurus.big-orange.net) by post.thorcom.com with esmtp (Exim 3.02 #1) id 118mOo-000005-00 for rsgb_lf_group@blacksheep.org; Mon, 26 Jul 1999 16:10:43 +0100 Received: from w8k3f0 ([143.179.151.62]) by Lesothosaurus.big-orange.net (Netscape Messaging Server 3.6) with SMTP id AAA4897; Mon, 26 Jul 1999 17:09:21 +0200 Message-ID: <002f01bed779$88e0c880$3e97b38f@w8k3f0> From: "Dick Rollema" <d.w.rollema@gironet.nl> To: "LF-Group" <rsgb_lf_group@blacksheep.org> Cc: "Ger van Went, PA0GER" <van.went@hetnet.nl>, "Hans Peltzer, PA0HRP" <peltzer@gironet.nl>, "Klaas Spaargaren, PA0KSB" <k.spaargaren@wxs.nl>, "Jan Hekkert, PA3HCD" <jhekkert@ichthus.lifenet.nl> Subject: LF: Signals measured Date: Mon, 26 Jul 1999 16:50:11 +0200 MIME-Version: 1.0 Content-Type: text/html; charset=windows-1252 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 Sender: <majordom@post.thorcom.com> Content-transfer-encoding: 8bit <!DOCTYPE HTML PUBLIC "-//W3C//DTD W3 HTML//EN"> <HTML> <HEAD> <META content=text/html;charset=iso-8859-1 http-equiv=Content-Type> <META content='"MSHTML 4.72.3110.7"' name=GENERATOR> </HEAD> <BODY bgColor=#ffffff> <DIV><FONT color=#000000 size=2>To All from PA0SE</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>For the second time I have been measuring signals received here.</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT size=2>The substitution method was used again: the output from the receiver is fed to a 35 Hz wide audio bandpass filter and then to headphones and an oscilloscope. The gain of the receiver is adjusted for a suitable deflection on the scope. Next a signal generator is substituted for the aerial and its output adjusted for the same deflection on the scope. The strength of the signal is then read from the attenuator and level meter of the sig gen. (HP 606B).</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2><STRONG>Date Time Call Input receiver Field strength S-report</FONT></STRONG></DIV> <DIV><FONT size=2><STRONG> UTC dBm dB(uV)/m</STRONG></FONT></DIV> <DIV><FONT size=2><STRONG></STRONG></FONT> </DIV> <DIV><FONT size=2>23/7 1725 DCF39 -33 65 S 9+40 dB</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>23/7 1846 G4GVC </FONT><FONT size=2> -84 13.9 S 7</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV> </DIV> <DIV><FONT size=2>24/7 0225 DCF39 -37 61 S 9+36 dB (weaker than at daytime!)</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>24/7 0700 DCF39 -32 66 S 9 + 41 dB</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>24/7 0710 G4GVC -83 16 S 7/8</FONT></DIV> <DIV><FONT size=2><STRONG></STRONG></FONT> </DIV> <DIV><FONT color=#000000 size=2>24/7 0729 GM/G3YXM/P -91 6.8 S 6</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>24/7 1029 PA0VBR -92 5.9 S 6 (new station, his first QSO)</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>25/7 0703 DCF39 -32 66 S 9 + 40 dB</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>25/7 0715 GM/G3YXM/P -93 4.9 S 5/6</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>25/7 0723 DL3FDO -96 1.2 S 5</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>25/7 0800 G4GVC -84 14 S 7</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>25/7 0845 G3KEV -80 18 S 8 </FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>25/7 0903 OZ1KMR -80 18 S 8</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>25/7 0907 OZ5N </FONT><FONT color=#000000 size=2> -88 10 S 6/7</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT size=2>25/7 0915 ON7YD -83 15 S 7/8</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>A pity I heard no more stations.</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT size=2>For the S-point calculation I used the IARU recommendation: S 9 = -73 dBm; 1 S-point = 6 dB</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>For the field strength I used the earlier found relation e/E = 2.83 in which e = voltage at the aerial terminal of the receiver in microvolt; E = field strength in V/m.</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>The accuracy gets worse as the signal received is nearer to the noise level. The noise also corrupts the picture on the scope screen and it becomes increasingly difficult to read the amplitude of the signal in a mixture of signal and noise.</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT size=2>The minimum discernible signal by ear and scope at my location is about -97 dBm (S 5 in 35 Hz bandwidth).</FONT></DIV> <DIV><FONT size=2>It means that if I hear a signal it must be at least S 5. It confirms my earlier finding that an S-report by ear on a weak signal tends to be pessimistic. For relatively strong signals reports by ear agree pretty well with measured ones. </FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>In a QSO with Dave, GM/G3YXM/P, I gave him S5 by ear and measured S 6.</FONT></DIV> <DIV><FONT size=2>Andries, PA0VBR got S 4 by ear and I measured S 6. </FONT></DIV> <DIV><FONT color=#000000 size=2>I must try to remember that for future QSO's.</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>Now on a entirely different subject.</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>Alan Melia in his e-mail of 18 July, 23.12 hrs, mentioned F5MLP as a station having difficulty in getting started on LF.</FONT></DIV> <DIV><FONT color=#000000 size=2>I think beginners like F5MLP would be well advised to buy the <EM>LF Experimenter's Source Book </EM>by Peter Dodd, G3LDO at the RSGB Shop (hope he can read English). It gives precisely the sort of information a beginner requires.</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>In my opinion a real amateur who likes to experiment should invest in Test Gear, Literature and a Personal Computer with suitable software.</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>By chance I came across a very good article: "PROPAGATION OF LONG RADIO WAVES" by J.A. Adcock, VK3ACA. It appeared in the Australian magazine <EM>Amateur Radio </EM>in 4 parts, June to September 1991.</FONT></DIV> <DIV><FONT color=#000000 size=2>The article provides a thorough treatment of the subject, starting off with basic concepts like refraction, reflection and diffraction.</FONT></DIV> <DIV><FONT color=#000000 size=2>It answered many questions I had about propagation at LF.</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>I found the article at and downloaded it from our VERON website: <A href="http://www.veron.nl">http://www.veron.nl</A>.</FONT></DIV> <DIV><FONT color=#000000 size=2>Next click on HAMRADIO and LF-BAND; you find the article under the heading ''Engelstalig". </FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>73, Dick, PA0SE</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>JO22GD</FONT></DIV> <DIV><FONT color=#000000 size=2>D.W. Rollema</FONT></DIV> <DIV><FONT color=#000000 size=2>V.d. Marckstraat 5</FONT></DIV> <DIV><FONT color=#000000 size=2>2352 RA Leiderdorp</FONT></DIV> <DIV><FONT color=#000000 size=2>The Netherlands</FONT></DIV> <DIV><FONT color=#000000 size=2>Tel. +31 71 589 27 34</FONT></DIV> <DIV><FONT color=#000000 size=2>E-mail: <A href="mailto:d.w.rollema@gironet.nl">d.w.rollema@gironet.nl</A></FONT></DIV></BODY></HTML>