Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-di02.r1000.mx.aol.com (Internet Inbound) with ESMTP id A7BDE380000AA; Fri, 25 Jan 2013 09:51:25 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Tykbn-0001ly-FU for rs_out_1@blacksheep.org; Fri, 25 Jan 2013 14:50:23 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Tykbm-0001lp-PQ for rsgb_lf_group@blacksheep.org; Fri, 25 Jan 2013 14:50:22 +0000 Received: from mail-qe0-f50.google.com ([209.85.128.50]) by relay1.thorcom.net with esmtps (TLSv1:RC4-SHA:128) (Exim 4.77) (envelope-from ) id 1Tykbj-0001h8-Bg for rsgb_lf_group@blacksheep.org; Fri, 25 Jan 2013 14:50:21 +0000 Received: by mail-qe0-f50.google.com with SMTP id 7so118356qea.37 for ; Fri, 25 Jan 2013 06:49:57 -0800 (PST) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:x-received:date:message-id:subject:from:to :content-type; bh=mS4qUFhlC+kiTDvCMi+CDkpbf1CwcmoMfy+eoW9y2gI=; b=wN8NEIk73Ul47p6N3ZRULsgdPRtpIjKGrcu1lCO1tkeb3j5PcakUMp/XUl7qDNW9hd QwhIS9LiilBc2TGx6M4wf/DUDBqwyVSGhXZNRfPEHKACreEKdX2splS68JworN+Gazrl q1Y+UZkJSIuwzIjqmnGAMbzY0ae59lbmv0Z8IbqLKbV+1TPptLjr2IcgsS3QdpXIPniv M1ehDOpongCrTS5pzncFDDf9DAEXP+EOLJmosO2QUrBuhdyK9wc3IK7fJeyEHDhfBYb7 hsUREHGLuRydTittei+sBkqq6u+cTg1Yi34F7oIwVq+t7vDy/PHG8E2uMyPD9k7Te5Vh 94eA== MIME-Version: 1.0 X-Received: by 10.229.206.16 with SMTP id fs16mr1482039qcb.69.1359125397591; Fri, 25 Jan 2013 06:49:57 -0800 (PST) Received: by 10.229.156.18 with HTTP; Fri, 25 Jan 2013 06:49:57 -0800 (PST) Date: Fri, 25 Jan 2013 14:49:57 +0000 Message-ID: From: Roger Lapthorn To: rsgb_lf_group@yahoogroups.co.uk, "rsgb_lf_group@blacksheep.org" , Mike Dennison , bernie , Chris Osborn , g4bao X-Spam-Score: -0.7 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Today I repeated my field measurements to establish the ERP of my 8W QRSS3 137.766kHz beacon feeding my earth-electrode antenna. This time I believe I did the measurement correctly. Here's how. 1. Travel 2km from the home QTH with E-field probe, FT817 and PC running Spectran. 2. Choose a location in the best direction for the "loop in the ground" so the measured signal strength is close to the maximum possible i.e. not off the sides of the loop. I chose a location due west free from wires, trees, pylons etc. 3. Set up FT817 so the RF gain is adjustable and turned well back and the AGC is inactive. 4. Tune in my LF beacon and adjust the RF gain to the lowest possible detection level. 5. Measure the S/N of my signal with Spectran and note reading. 6. Retune to the German commercial station DCF39 (138.830kHz) and, without adjusting the RF gain at all, measure the S/N with Spectran. 7. Repeat these measurements 5 times. 8. Calculate the difference in dB between my signal and DCF39, in my case *41.3dB* 9. Using the assumption that DCF39 has a field strength of 1mV/m, work out my own field strength: *9uV/m* 10. Using the formula ERP = (E^2 * d^2)/49 work out the ERP. [...] Content analysis details: (-0.7 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [209.85.128.50 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (rogerlapthorn[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: 21e2055b299bd63ed331c37c8a3e15ca Subject: LF: My 137.766kHz ERP is approx 6.6uW Content-Type: multipart/alternative; boundary=0016e68ee29887575904d41e0adc X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=HTML_MESSAGE autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false x-aol-global-disposition: G X-AOL-SCOLL-AUTHENTICATION: mtain-di02.r1000.mx.aol.com ; domain : gmail.com DKIM : fail x-aol-sid: 3039ac1da60651029bed4022 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none --0016e68ee29887575904d41e0adc Content-Type: text/plain; charset=ISO-8859-1 Today I repeated my field measurements to establish the ERP of my 8W QRSS3 137.766kHz beacon feeding my earth-electrode antenna. This time I believe I did the measurement correctly. Here's how. 1. Travel 2km from the home QTH with E-field probe, FT817 and PC running Spectran. 2. Choose a location in the best direction for the "loop in the ground" so the measured signal strength is close to the maximum possible i.e. not off the sides of the loop. I chose a location due west free from wires, trees, pylons etc. 3. Set up FT817 so the RF gain is adjustable and turned well back and the AGC is inactive. 4. Tune in my LF beacon and adjust the RF gain to the lowest possible detection level. 5. Measure the S/N of my signal with Spectran and note reading. 6. Retune to the German commercial station DCF39 (138.830kHz) and, without adjusting the RF gain at all, measure the S/N with Spectran. 7. Repeat these measurements 5 times. 8. Calculate the difference in dB between my signal and DCF39, in my case *41.3dB* 9. Using the assumption that DCF39 has a field strength of 1mV/m, work out my own field strength: *9uV/m* 10. Using the formula ERP = (E^2 * d^2)/49 work out the ERP. Answer? *My measured ERP on 137.766kHz is approximately 6.6uW* Caveats: 1. If DCF39 is not approx 1mV/m then the ERP needs to be adjusted up or down proportionally. 2. Measurement error is approx +/- 2dB. Stations who have managed to receive this beacon (best DX so far 56.7 and 61km) are doing very well. *The QRPp QRSS3 beacon is still running over the weekend and more reports would be appreciated.* 73s Roger G3XBM -- http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk https://sites.google.com/site/sub9khz/ http://qss2.blogspot.com/ http://www.youtube.com/user/G3XBM --0016e68ee29887575904d41e0adc Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
Today I repeated my field measurements to establ= ish the ERP of my 8W QRSS3 137.766kHz beacon feeding my earth-electrode antenna. This time I be= lieve I did=20 the measurement correctly. Here's how.
  1. Travel 2km from the home QTH with E-field probe, FT817 and PC runni= ng Spectran.
  2. Choose a location in the best direction for the "= loop in the ground" so the measured signal strength is close to the ma= ximum possible i.e.=20 not off the sides of the loop. I chose a location due west free from wires,= trees, pylons etc.
  3. Set up FT817 so the RF gain is adjustable a= nd turned well back and the AGC is inactive.
  4. Tune in my LF beacon a= nd adjust the RF gain to the lowest possible detection level.
  5. Measure the S/N of my signal with Spectran and note reading.
  6. Re= tune to the German commercial station DCF39 (138.830kHz) and, without adjus= ting the RF gain at all, measure the S/N with Spectran.
  7. Repeat thes= e measurements 5 times.
  8. Calculate the difference in dB between my signal and DCF39, in my case = 41.3dB
  9. Using the assumption that DCF39 has a field strength = of 1mV/m, work out my own field strength: 9uV/m
  10. Using th= e formula ERP =3D (E^2 * d^2)/49 work out the ERP.
Answer? =A0 =A0 My measured ERP on 137.766kHz is approximately 6.6uW<= /b>

Caveats:
  1. If DCF39 is not approx 1mV/m then the ERP needs to be adjusted up o= r down proportionally.
  2. Measurement error is approx +/- 2dB.
    3. Stations who have managed to receive this beacon (best DX so far 56.7 and 6= 1km) are doing very well.

    The QRPp QRSS3=A0 beacon is still ru= nning over the weekend and more reports would be appreciated.

73s
Roger G3XBM
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