Return-Path: Received: from mtain-dg02.r1000.mx.aol.com (mtain-dg02.r1000.mx.aol.com [172.29.65.10]) by air-dc05.mail.aol.com (v126.13) with ESMTP id MAILINDC051-86014b5b0bf92fc; Sat, 23 Jan 2010 09:47:21 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dg02.r1000.mx.aol.com (Internet Inbound) with ESMTP id 48DC838000047; Sat, 23 Jan 2010 09:47:20 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NYhFy-0005om-M7 for rs_out_1@blacksheep.org; Sat, 23 Jan 2010 14:46:34 +0000 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NYhFy-0005od-45 for rsgb_lf_group@blacksheep.org; Sat, 23 Jan 2010 14:46:34 +0000 Received: from mail-bw0-f221.google.com ([209.85.218.221]) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NYhFv-00061Y-PA for rsgb_lf_group@blacksheep.org; Sat, 23 Jan 2010 14:46:34 +0000 Received: by bwz21 with SMTP id 21so1730856bwz.4 for ; Sat, 23 Jan 2010 06:46:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type; bh=Q274Q1Q0ewYJo88VoM1ruGcJPcowNVd+u9wOemlj0cU=; b=tWYjzUDvVZY455I/oiSqTKy1x5ABCHWOiGzJNuwxjPEmn18TxMNcKMraUtAsmpe174 kgKauf0XtKY45nwBS1AxQ2t9qgy1KXu2ixmf66gMYdDefphVy6hyGXH+Dmv9+GwFO1Is TacdNpM2w9P+RM7TiXnGqXf1QHyr3/NFxZ8mQ= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=D+nPpNJc/PHyY0EVOzHbTcpoz7a1lTKq6VcXjWzg4BM7XmkMenkr30qBrHCCcofrw9 OXOqPVO64D3zUakyYzXwDl8Raxvb0EItCAgATu1I9VqKte606ro0ikgqmAgY0HDOTizT ms8vFYKhNRAzkAClyajBlaFkko6WQmBjFvxeE= MIME-Version: 1.0 Received: by 10.204.9.150 with SMTP id l22mr2307795bkl.171.1264257986188; Sat, 23 Jan 2010 06:46:26 -0800 (PST) In-Reply-To: <20100123151204.tm00cc8fmogkc80g@webmail6.kuleuven.be> References: <9afca2641001230502q45fb0825n3ee7dca1774c95eb@mail.gmail.com> <20100123151204.tm00cc8fmogkc80g@webmail6.kuleuven.be> Date: Sat, 23 Jan 2010 14:46:25 +0000 Message-ID: <9afca2641001230646l55038t2e03f54f763a829a@mail.gmail.com> From: Roger Lapthorn To: rsgb_lf_group@blacksheep.org DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: G3XBM's ERP on 500kHz Content-Type: multipart/alternative; boundary=00151758a6762bd6e4047dd600d5 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,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-sid: 3039ac1d410a4b5b0bf87f87 X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) --00151758a6762bd6e4047dd600d5 Content-Type: text/plain; charset=ISO-8859-1 Thanks Rik. It is good to know that the your figures more or less agree having done some proper simulations. Is it possible to email me these simulations please? 73s Roger G3XBM On 23 January 2010 14:12, Rik Strobbe wrote: > Roger, > > I simulated the antenna based on your description (with MMANA) and the > current through the vertical wire seems to be quite constant. So the tophat > works well and the effective height will be more or less the physical > height. > The simulation gives a radiation resistance of 0.074 Ohm, so with 0.12 A a > radiated power just over 1mW EMRP (1.75mW ERP). > In the real world it will be some dB's less (as Jim stated recently), > probably something like 0,5 to 1mW ERP. > > Very impressive that it covers over 1200km. > > 73, Rik ON7YD - OR7T > > > Quoting Roger Lapthorn : > > All, >> >> Yesterday I did a recalculation of the G3XBM ERP based on the classic >> formula and re-measurements of my antenna current. My antenna is a 5m long >> vertical with a spiral top hat of about 7 turns about 1.5m x 1.5m. Not >> being clear how to model the top hat I assumed effective heights of 5, 4 or >> 3m. The measured antenna current is 0.12A. >> >> My results are as follows: >> >> Assumed effective height 5m ERP = 1.53mW >> Assumed effective height 4m ERP = 0.98mW >> Assumed effective height 3m ERP = 0.55mW >> >> So, I believe my 1mW ERP previously calculated is not a bad estimate, and >> it may indeed be lower than this figure. >> >> 73s >> Roger G3XBM >> -- >> >> http://g3xbm-qrp.blogspot.com/ >> http://www.g3xbm.co.uk >> http://www.youtube.com/user/G3XBM >> G3XBM GQRP 1678 ISWL G11088 >> >> > > > -- http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/G3XBM G3XBM GQRP 1678 ISWL G11088 --00151758a6762bd6e4047dd600d5 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Thanks Rik.

It is good to know that the your figures more or less= agree having done some proper simulations. Is it possible to email me the= se simulations please?

73s
Roger G3XBM

On 23 January 2010 14:12, Rik Strobbe <Rik.Strobbe@fys.kuleuven.be> wrote:
Roger,

I simulated the antenna based on your description (with MMANA) and the cur= rent through the vertical wire seems to be quite constant. So the tophat= works well and the effective height will be more or less the physical hei= ght.
The simulation gives a radiation resistance of 0.074 Ohm, so with 0.12 A= a radiated power just over 1mW EMRP (1.75mW ERP).
In the real world it will be some dB's less (as Jim stated recently),= probably something like 0,5 to 1mW ERP.

Very impressive that it covers over 1200km.

73, Rik =A0ON7YD - OR7T


Quoting Roger Lapthorn <rogerlapthorn@gmail.com>:

All,

Yesterday I did a recalculation of the G3XBM ERP based on the =A0classic= formula and re-measurements of my antenna current. My =A0antenna is a 5m= long vertical with a spiral top hat of about 7 turns =A0about 1.5m x 1.5m= . Not being clear how to model the top hat I =A0assumed effective heights= of 5, 4 or 3m. The measured antenna =A0current is 0.12A.

My results are as follows:

Assumed effective height 5m =A0 =A0 ERP =3D 1.53mW
Assumed effective height 4m =A0 =A0 ERP =3D 0.98mW
Assumed effective height 3m =A0 =A0 ERP =3D 0.55mW

So, I believe my 1mW ERP previously calculated is not a bad =A0estimate,= and it may indeed be lower than this figure.

73s
Roger G3XBM
--

http://g3xbm-= qrp.blogspot.com/
http://www.g3xbm.co.u= k
http://www= .youtube.com/user/G3XBM
G3XBM =A0 =A0GQRP 1678 =A0 =A0 =A0ISWL G11088







--

http://g3xbm-qrp.blogspot.com/http://www.g3xbm.co.uk
http://www.youtube.com/user/G3XBM
G3XBM =A0 =A0GQRP 1678 =A0 =A0 =A0ISWL G11088
--00151758a6762bd6e4047dd600d5--