Return-Path: Received: from mtain-de10.r1000.mx.aol.com (mtain-de10.r1000.mx.aol.com [172.29.64.210]) by air-md10.mail.aol.com (v129.4) with ESMTP id MAILINMD104-8b9f4c95051729; Sat, 18 Sep 2010 14:29:43 -0400 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-de10.r1000.mx.aol.com (Internet Inbound) with ESMTP id 764CB3800016A; Sat, 18 Sep 2010 14:29:41 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Ox28r-0008A7-7N for rs_out_1@blacksheep.org; Sat, 18 Sep 2010 19:28:05 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Ox28g-00089y-NP for rsgb_lf_group@blacksheep.org; Sat, 18 Sep 2010 19:27:54 +0100 Received: from relay.uni-heidelberg.de ([129.206.100.212]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Ox28f-0002KC-Un for rsgb_lf_group@blacksheep.org; Sat, 18 Sep 2010 19:27:55 +0100 Received: from ix.urz.uni-heidelberg.de (cyrus-portal.urz.uni-heidelberg.de [129.206.100.176]) by relay.uni-heidelberg.de (8.14.1/8.14.1) with ESMTP id o8IIRMWl007256 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sat, 18 Sep 2010 20:27:23 +0200 Received: from extmail.urz.uni-heidelberg.de (extmail.urz.uni-heidelberg.de [129.206.100.140]) by ix.urz.uni-heidelberg.de (8.13.8/8.13.8) with ESMTP id o8IIRqB7032565 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sat, 18 Sep 2010 20:27:52 +0200 Received: from [147.142.13.124] (vpn513-124.rzuser.uni-heidelberg.de [147.142.13.124]) by extmail.urz.uni-heidelberg.de (8.13.4/8.13.1) with ESMTP id o8IIRaKr017365 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sat, 18 Sep 2010 20:27:37 +0200 Message-ID: <4C9504C1.7010305@iup.uni-heidelberg.de> Date: Sat, 18 Sep 2010 20:28:17 +0200 From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.11) Gecko/20100711 Thunderbird/3.0.6 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <4C94FBCA.1060802@iup.uni-heidelberg.de> In-Reply-To: X-Spam-Score: 1.6 (+) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,HTML_TAG_EXIST_TBODY=0.126,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: 137.5kHz WSPR success Content-Type: multipart/alternative; boundary="------------030806070308060503000201" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.9 required=5.0 tests=HTML_30_40,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: S X-AOL-REROUTE: YES x-aol-sid: 3039ac1d40d24c95051501c5 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none X-Mailer: Unknown (No Version) --------------030806070308060503000201 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay.uni-heidelberg.de id o8IIRMWl007256 Roger, This sound very hopefully and enthusiastic :-) What is the area of your=20 loop? And what is the "gain" compared to the earth antenna? Will you=20 give up the earth antenna project? And what about your ULF (838 Hz) tests? For the IRF510 you can allow 20...25 V supply voltage, if well matched,=20 so if the voltage is now 12...13.8 V you can double the voltage and get=20 6 dB more power, so maybe twice the distance :-) 73 and keep us informated! Stefan/DK7FC Am 18.09.2010 20:06, schrieb Roger Lapthorn: > Hi Stefan (et al), > > Still using the single IRF510 but driving it with a better square wave= =20 > now. I hope to change the design tomorrow to run from a higher supply=20 > rail and realise another 3-4dB or so of ERP. The other simple change I= =20 > can make (later) is with my loop antenna, which is made from wire only= =20 > 1mm diameter. Increasing this to 4-5mm wire should reduce the losses=20 > another 3dB or more. I can also try running the lower part nearer the=20 > ground thereby increasing the loop area by another 20%. However this=20 > may introduce other losses. > > So far I am pleased with the results: with only around 4-5W from the=20 > PA, a very simple loop antenna with thin wire, tuned with a simple ATU= =20 > on the bedroom table using just a standard capacitance decade box, a=20 > simple 3C90 step-down transformer and a current meter, I've now been=20 > heard/seen by 4 different stations in SE England and the WSPR reports=20 > already suggest further is possible. > > This autumn is going to be a bundle of fun! > > 73s > Roger G3XBM > > > 2010/9/18 Stefan Sch=E4fer > > > Hello Roger, > > Congrats to that distance and to the PA :-) Which FET is in use > now? And how is the driver realised? > > 73 and GL, > > Stefan/DK7FC > > Am 18.09.2010 12:54, schrieb Roger Lapthorn: >> Some success this morning with my second ever 137kHz WSPR report, >> this time from *G3XIZ* who got me up to -23dB S/N during the >> morning. According to the WSPR database the distance is 46km. >> BTW, the PA is running about 5W RF out (ERP about 10-20uW) in >> class-E with a nice cool heatsink. Next steps will be to increase >> the power and ERP. >> >> 2010-09-18 08:50 *G3XBM * 0.137534 -23 -1 JO02d= g >> 0.001 G3XIZ IO92ub 46 240 >> >> >> Many thanks Chris, and everyone else please keep looking! >> >> 73s >> Roger G3XBM >> >> --=20 >> http://g3xbm-qrp.blogspot.com/ >> http://www.g3xbm.co.uk >> http://www.youtube.com/user/g3xbm >> G3XBM GQRP 1678 ISWL G11088 > > > > > --=20 > http://g3xbm-qrp.blogspot.com/ > http://www.g3xbm.co.uk > http://www.youtube.com/user/g3xbm > G3XBM GQRP 1678 ISWL G11088 --------------030806070308060503000201 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Roger,

This sound very hopefully and enthusiastic :-) What is the area of your loop? And what is the "gain" compared to the earth antenna? Will you give up the earth antenna project? And what about your ULF (838 Hz) tests?

For the IRF510 you can allow 20...25 V supply voltage, if well matched, so if the voltage is now 12...13.8 V you can double the voltage and get 6 dB more power, so maybe twice the distance :-)

73 and keep us informated!

Stefan/DK7FC


Am 18.09.2010 20:06, schrieb Roger Lapthorn:
Hi Stefan (et al),

Still using the single IRF510 but driving it with a better square wave now. I hope to change the design tomorrow to run from a higher supply rail and realise another 3-4dB or so of ERP. The other simple change I can make (later) is with my loop antenna, which is made from wire only 1mm diameter. Increasing this to 4-5mm wire should reduce the losses another 3dB or more. I can also try running the lower part nearer the ground thereby increasing the loop area by another 20%. However this may introduce other losses.

So far I am pleased with the results: with only around 4-5W from the PA, a very simple loop antenna with thin wire, tuned with a simple ATU on the bedroom table using just a standard capacitance decade box, a simple 3C90 step-down transformer and a current meter, I've now been heard/seen by 4 different stations in SE England and the WSPR reports already suggest further is possible.

This autumn is going to be a bundle of fun!

73s
Roger G3XBM


2010/9/18 Stefan Schäfer <schaefer@iup.uni-heidelberg.de>
Hello Roger,

Congrats to that distance and to the PA :-) Which FET is in use now? And how is the driver realised?

73 and GL,

Stefan/DK7FC

Am 18.09.2010 12:54, schrieb Roger Lapthorn:
Some success this morning with my second ever 137kHz WSPR report, this time from G3XIZ who got me up to -23dB S/N during the morning. According to the WSPR database the distance is 46km. BTW, the PA is running about 5W RF out (ERP about 10-20uW) in class-E with a nice cool heatsink. Next steps will be to increase the power and ERP.

 2010-09-18 08:50   G3XBM   0.137534   -23   -1   JO02dg   0.001   G3XIZ   IO92ub   46   240 

Many thanks Chris, and everyone else please keep looking!

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
--------------030806070308060503000201--