Return-Path: <owner-rsgb_lf_group@blacksheep.org>
Received: from mtain-de09.r1000.mx.aol.com (mtain-de09.r1000.mx.aol.com [172.29.64.209]) by air-di06.mail.aol.com (v129.4) with ESMTP id MAILINDI063-eacc4c61d59eef; Tue, 10 Aug 2010 18:41:34 -0400
Received: from post.thorcom.com (post.thorcom.com [193.82.116.20])
by mtain-de09.r1000.mx.aol.com (Internet Inbound) with ESMTP id 2E3803800008A;
Tue, 10 Aug 2010 18:41:33 -0400 (EDT)
Received: from majordom by post.thorcom.com with local (Exim 4.14)
id 1OixU7-00085B-Lk
for rs_out_1@blacksheep.org; Tue, 10 Aug 2010 23:39:51 +0100
Received: from [193.82.116.32] (helo=relay1.thorcom.net)
by post.thorcom.com with esmtp (Exim 4.14)
id 1OixU7-000852-88
for rsgb_lf_group@blacksheep.org; Tue, 10 Aug 2010 23:39:51 +0100
Received: from smtp815.mail.ukl.yahoo.com ([217.12.12.244])
by relay1.thorcom.net with smtp (Exim 4.63)
(envelope-from <alan.melia@btinternet.com>)
id 1OixU5-0006VB-LI
for rsgb_lf_group@blacksheep.org; Tue, 10 Aug 2010 23:39:51 +0100
Received: (qmail 64000 invoked from network); 10 Aug 2010 22:39:43 -0000
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws;
s=s1024; d=btinternet.com;
h=DKIM-Signature:Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:From:To:References:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE:X-Antivirus:X-Antivirus-Status;
b=TQT2U7gv7zRryH6FBDovgv05FoPif3DRZHw6GmreWdqCrrROJq7miTuU4c0GRG090dplMoDwer1oIjJUHDDIAEbIO3uNbzg9GKNcCKVFIhwBqNq33m8VnPNnASMzL5DkMbIdhUVwDYoDSyEe/BGc52w0PYys7IBhjgLwGE80xQ4= ;
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=btinternet.com; s=s1024; t=1281479983; bh=x+eKDBflatasAjaneKXzMJDsYTQaHLfG15WfGghO41I=; h=Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:From:To:References:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE:X-Antivirus:X-Antivirus-Status; b=1fYEoybbUzcpUFX47RSZqzUuNAOsdaDYcSkmyfup5jFl3OwEqUh/nue93KPLxRyr0i5zg3cEuVvddZze7i8xSXrSs/S9++8Wx9QPBJRQ3ikBqBgfraOeGkzynGntl6tEKsPq63qS/kLBqbHh6lIIKw9C4SsFS4r7KRrtQtQIM+k=
Received: from lark (alan.melia@86.145.241.226 with login)
by smtp815.mail.ukl.yahoo.com with SMTP; 10 Aug 2010 22:39:43 +0000 GMT
X-Yahoo-SMTP: fpz.2VeswBBs59bVshRPmMN51lcO2lgFRIvE4XTqE8dRwOxd70E-
X-YMail-OSG: b.4mGbMVM1nmVRhCVc.eHMWtBxiseyBr6MzhB7de.CK6qS9
fkEIyqTXt0p3YC1XyXZTdgBAMB2K7kAcG52e.i4UMPp_uhiIbfmEkdTkcG5j
uUYd1TN6kyy3yJOD4LFsdU4OtZKkGZa26jsOaXftNjXtJbEjgYDRQ9lhMtLH
SLwTVgMxAOuD3X_DZ19LlYeNfbgBItW8xb8CVc_UPWgXlq.Ufkf7mzzZnf.z
UFt8nQJg6ZMz0f53DyXmScKv_x8HzvehBH.ip8PhKcoOLezrgtCLPkRU-
X-Yahoo-Newman-Property: ymail-3
Message-ID: <009101cb38dc$f0b119d0$4001a8c0@lark>
From: "Alan Melia" <alan.melia@btinternet.com>
To: "RSGB LF Gp" <rsgb_lf_group@blacksheep.org>
References: <AANLkTi=WfnnC0rPFdFd8ec=QR4Jdi8fDk_VfVsx17S3i@mail.gmail.com>
Date: Tue, 10 Aug 2010 23:39:44 +0100
MIME-Version: 1.0
X-Priority: 3
X-MSMail-Priority: Normal
X-Mailer: Microsoft Outlook Express 6.00.2800.2001
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.2001
X-Antivirus: avast! (VPS 100810-1, 10/08/2010), Outbound message
X-Antivirus-Status: Clean
DomainKey-Status: good (testing)
X-Spam-Score: 0.0 (/)
X-Spam-Report: autolearn=disabled,UNPARSEABLE_RELAY=0.001
Subject: LF: Re: 136kHz ERP calculation
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
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=none 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: mail_rly_antispam_dkim-d227.2 ; domain : btinternet.com DKIM : fail
x-aol-sid: 3039ac1d40d14c61d59d2d50
X-AOL-IP: 193.82.116.20
X-AOL-SPF: domain : blacksheep.org SPF : none
Hi Roger you can calibrate your loop first using DCF39 on 138.83. This has a
field strength in our area of 1mV/m. Then you could work back your own ERP
by comparison...... 1W ERP produces 300mV/m at 1km, 100mV/m at 10km (from
memory ....I think that is correct....10dB per decade after 1km). Doing it
that way removes as lot of the variables, and its a good thumbnail
calculation.
Alan G3NYK
----- Original Message -----
From: "Roger Lapthorn" <rogerlapthorn@gmail.com>
To: <rsgb_lf_group@blacksheep.org>; <rogerlapthorn@gmail.com>
Sent: Tuesday, August 10, 2010 7:09 PM
Subject: LF: 136kHz ERP calculation
> *My last post didn't appear, so this is a retry...*
>
> About a week ago I recorded my 136kHz QRP beacon (2W from PA, QRSS3, using
> just 20m separated earth electrodes as the antenna) at 14.9km away from
the
> QTH using Spectran with a 30t, 80cm loop, Hi-Z matching into the FT817.
>
> I'm wondering if someone here is able to *work out the ERP* that I must be
> achieving please. These are the numbers I have:
>
> Spectran signal level -42.5dB
> Resolution 0.17Hz
> Sampling rate 11025
> Distance (Rx from TX) 14.9km
>
> It surprises me that the signal can be seen so well at this distance with
> such low power and with this "antenna" set-up. Thanks in advance for any
> help and please excuse my ignorance.
>
> 73s
> Roger G3XBM
>
> --
> http://g3xbm-qrp.blogspot.com/
> http://www.g3xbm.co.uk
> http://www.youtube.com/user/g3xbm
> G3XBM GQRP 1678 ISWL G11088
>