Return-Path: Received: from mtain-dj06.r1000.mx.aol.com (mtain-dj06.r1000.mail.aol.com [172.19.187.142]) by air-mc06.mail.aol.com (v129.4) with ESMTP id MAILINMC064-a9764d2cae7d234; Tue, 11 Jan 2011 14:24:45 -0500 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dj06.r1000.mx.aol.com (Internet Inbound) with ESMTP id 4F9183800009E; Tue, 11 Jan 2011 14:24:43 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Pcjoq-0002vC-HZ for rs_out_1@blacksheep.org; Tue, 11 Jan 2011 19:23:48 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Pcjop-0002v3-Oz for rsgb_lf_group@blacksheep.org; Tue, 11 Jan 2011 19:23:47 +0000 Received: from mail-iw0-f171.google.com ([209.85.214.171]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Pcjom-0001qL-Vy for rsgb_lf_group@blacksheep.org; Tue, 11 Jan 2011 19:23:47 +0000 Received: by iwn2 with SMTP id 2so20780219iwn.16 for ; Tue, 11 Jan 2011 11:23:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:content-type; bh=NMmDbiWzAyVn4gL+WU/XfpSG8UAtPsZ9t/6s7huEXyE=; b=v2K/vviZsaTj/FFFi3seLzds1H0j3/q2zM+8DiJk7uENmYCbOJy0h7L0Hy7aaGKDO2 AwXEf4xTulTlCSnLJw7uDe056jl3884rt4pFV0O5zo9ghyQltPOsGdFMQ0LyO8vgzxU4 DV8/mCp/sYhVhuXaoWXzxDd1Pr+jQH1TkI4Jc= 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=kPgxeLLrmLHYbljWyG8HOV7kLfyUDr+MNRKoWsXe0FDjK7cO2j+nBZS3v03riv18nT EatnUUlBQmR07n1wjLfXReO4qRf1PVal7sL2PuG/XHYLM1LNuZxRWkom29mqu8t/wp+c 9WAohHbqXTAFSze9OGy8XCRmbacRLmzqkWm2c= MIME-Version: 1.0 Received: by 10.231.35.131 with SMTP id p3mr30208361ibd.87.1294773581414; Tue, 11 Jan 2011 11:19:41 -0800 (PST) Received: by 10.231.200.211 with HTTP; Tue, 11 Jan 2011 11:19:41 -0800 (PST) In-Reply-To: References: <4D2CA71C.5070808@iup.uni-heidelberg.de> Date: Tue, 11 Jan 2011 19:19:41 +0000 Message-ID: From: Andy Talbot To: rsgb_lf_group@blacksheep.org DomainKey-Status: good (testing) X-Spam-Score: 0.1 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,HTML_TAG_EXIST_TBODY=0.126 Subject: Re: LF: Re: Increased ERP on 137.5kHz - WSPR reports please Content-Type: multipart/alternative; boundary=00032557a2ba628193049996f71b X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.2 required=5.0 tests=HTML_FONTCOLOR_UNSAFE, HTML_MESSAGE,HTML_TAG_EXISTS_TBODY 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-d012.1 ; domain : gmail.com DKIM : pass x-aol-sid: 3039cdbc9d0b4d2cae7b2e3c X-AOL-IP: 195.171.43.25 X-Mailer: Unknown (No Version) --00032557a2ba628193049996f71b Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable If I understand corrrctly, you're measuring the current into the tap then? In any case, I doubt a ferrite rod even at that power could be linear as= a loading coil For example :: Using the approximation of 6pF /metre, antenna cap =3D 18pF. Lets call it 25pF to allows for strays. That will need 53mH to resonate, and Xc / Xl =3D j46k ohms. If you *were* to have 180mA flowing in the antenna, it would therefore hav= e around 8kV on it. If we assume a ferrite rod 8mm diameter, X sectional area =3D 50mm^2, and allow a Bmax of 0.2 Tesla Using V =3D 4.44.F,N.A.B it will need 270 turns to avoid saturation. Which I'm guessing it hasn't got. If it has, it'll be very thin wire that can't take 8kV Andy 'JNT/'IMR On 11 January 2011 19:04, Roger Lapthorn wrote: > My Marconi is just my 28MHz halo and its short coax feed (strapped) fed= via > an indoors ferrite rod inductor which is tuned and tapped. So most of th= e > current is NOT flowing in the vertical section. I need to set to work on > erecting a "real" vertical and a real matching network. There is no excu= se. > > The loop produces a signal that has been received at 148km (and quite > consistently at 46km) despite the low ERP (recalculated as around 200uW > based on the current flowing in the loop), so if I can get a more effect= ive > vertical, rather than my poor attempt today, there is hope. > > 73s > Roger G3XBM > > 2011/1/11 Stefan Sch=E4fer > > Roger, >> >> Maybe there was a kind of "utilities assisted earth mode" on the loop= at >> 3 km distance, as you call it? How high is the antenna and where is is >> placed? I hope its on the roof of the house :-) If its near a wet tree= and >> just 3m long, it may be worse than the loop. How do you measure the >> resonance? If you measure the antenna current, how high is it? >> I think you are on the right way to make your signal detectable in high= er >> distances! Good luck! >> >> 73, Stefan/DK7FC >> >> Am 11.01.2011 19:26, schrieb Roger Lapthorn: >> >> So much for the theory then.... >> >> The signal level at G6ALB in the next village (3km although WSPR shows= it >> as 0km) is some 10dB *down* on my loop antenna. Not sure if I got my su= ms >> wrong or there is some unexplained loss. The RX system at G6ALB is >> unchanged. >> >> 73s >> Roger G3XBM >> >> On 11 January 2011 17:32, Roger Lapthorn wrot= e: >> >>> Dear All, >>> >>> Today I rigged up and matched a simple, small, Marconi vertical on 136= kHz >>> instead of the vertical loop. Based on measurements of antenna current= and >>> some reasonable assumptions of effective height, I now believe I have= around >>> 200uW ERP on the band - heck this is *high* power for me! >>> >>> From now until late this evening I will run the WSPR beacon (136kHz US= B >>> dial) in the hope that a few more people will be able to copy the QRPp >>> signal. Please have a go and let me have any reports. >>> >>> 73s and good luck >>> >>> Roger G3XBM >>> >>> -- >>> g3xbm-qrp.blogspot.com/ >>> www.g3xbm.co.uk >>> www.youtube.com/user/g3xbm >>> G3XBM GQRP 1678 ISWL G11088 >>> >> >> >> >> -- >> g3xbm-qrp.blogspot.com/ >> www.g3xbm.co.uk >> www.youtube.com/user/g3xbm >> G3XBM GQRP 1678 ISWL G11088 >> >> >> >> >> >> > > > -- > g3xbm-qrp.blogspot.com/ > www.g3xbm.co.uk > www.youtube.com/user/g3xbm > G3XBM GQRP 1678 ISWL G11088 > > > > > > --00032557a2ba628193049996f71b Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
If I understand corrrctly, you're measuring the current into the= tap then?
In any case, I doubt a ferrite rod even at that power could be linear= as a loading coil
For example=A0::
=A0
Using the approximation of 6pF /metre, antenna cap =3D 18pF.=A0 Lets= call it=A025pF to allows for strays.=A0=A0
That will need 53mH to resonate, and Xc / Xl =3D=A0 j46k ohms.=A0=A0= =A0=A0=A0
If you were to have 180mA flowing in the antenna, it= would therefore=A0have around 8kV on it.=A0
=A0
If we assume a ferrite rod 8mm diameter,=A0 X sectional area=A0=3D 50= mm^2, and allow a Bmax of 0.2 Tesla
Using V =3D 4.44.F,N.A.B=A0=A0it will=A0need 270 turns to avoid satur= ation.=A0=A0=A0
Which I'm guessing it hasn't got.=A0 If it has, it'll be= very thin wire that can't take 8kV
=A0
Andy
'JNT/'IMR

On 11 January 2011 19:04, Roger Lapthorn <rogerlapthorn@= gmail.com> wrote:
My Marconi is just my 28MHz ha= lo and its short coax feed (strapped) fed via an indoors ferrite rod induc= tor which is tuned and tapped. So most of the current is NOT flowing in th= e vertical section. I need to set to work on erecting a "real"= vertical and a real matching network. There is no excuse.

The loop produces a signal that has been received at 148km (and quite= consistently at 46km) despite the low ERP (recalculated as around 200uW= based on the current flowing in the loop), so if I can get a more effecti= ve vertical, rather than my poor attempt today, there is hope.

73s
Roger G3XBM

2011/1/11 Stefan Sch= =E4fer <schaefer@iup.uni-heidelberg.de>=20

Roger,

Maybe there was a= kind of=A0 "utilities assisted earth mode" on the loop at 3 km= distance, as you call it? How high is the antenna and where is is placed?= I hope its on the roof of the house :-) If its near a wet tree and just= 3m long, it may be worse than the loop. How do you measure the resonance?= If you measure the antenna current, how high is it?
I think you are on the right way to make your signal detectable in higher= distances! Good luck!

73, Stefan/DK7FC

Am 11.01.2011 19:26,= schrieb Roger Lapthorn:=20
So much for the theory then....

The signa= l level at G6ALB in the next village (3km although WSPR shows it as 0km)= is some 10dB down on my loop antenna. Not sure if I got my sums wr= ong or there is some unexplained loss. The RX system at G6ALB is unchanged= .

73s
Roger G3XBM

On 11 January 2011 17:= 32, Roger Lapthorn <rogerlapthorn@gmail.com> wrote:<= br>
Dear All,

= Today I rigged up and matched a simple, small, Marconi vertical on 136kHz= instead of the vertical loop. Based on measurements of antenna current an= d some reasonable assumptions of effective height, I now believe I have ar= ound 200uW ERP on the band - heck this is high power for me!

From now until late this evening I will run the WSPR beacon (136kHz US= B dial) in the hope that a few more people will be able to copy the QRPp= signal. Please have a go and let me have any reports.

73s and good= luck

Roger G3XBM

--
g3xbm-qrp.blogspot.= com/
www.g3xb= m.co.uk
www.youtub= e.com/user/g3xbm
G3XBM=A0=A0 GQRP 1678=A0=A0=A0 ISWL G11088



--
g3xbm-qrp.blogspot.com/
www.g3xbm.co.uk<= br>www.you= tube.com/user/g3xbm
G3XBM=A0=A0 GQRP 1678=A0=A0=A0 ISWL G11088
3D""
=A0 =A0

=A0
=3D"" =A0 =3D"" =A0 =A0 =A0
=A0
=A0

<= /tbody>





--
g3xbm-qrp.blogspot.com/
www.g3xbm.co.uk
www.youtube.= com/user/g3xbm
G3XBM=A0=A0 GQRP 167= 8=A0=A0=A0 ISWL G11088
3D""
=A0 =A0
=A0
=3D"" =A0 =3D"" =A0 =A0 =A0
=A0
=A0

--00032557a2ba628193049996f71b--