Return-Path: Received: from mtain-mj06.r1000.mx.aol.com (mtain-mj06.r1000.mail.aol.com [172.21.164.90]) by air-mc04.mail.aol.com (v129.4) with ESMTP id MAILINMC043-a9314c889707b2; Thu, 09 Sep 2010 04:12:55 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-mj06.r1000.mx.aol.com (Internet Inbound) with ESMTP id 35A9A380000BB; Thu, 9 Sep 2010 04:12:53 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OtcEY-0008Ep-M0 for rs_out_1@blacksheep.org; Thu, 09 Sep 2010 09:11:50 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OtcEX-0008Eg-PD for rsgb_lf_group@blacksheep.org; Thu, 09 Sep 2010 09:11:49 +0100 Received: from smtp818.mail.ird.yahoo.com ([77.238.189.18]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1OtcES-0004II-MW for rsgb_lf_group@blacksheep.org; Thu, 09 Sep 2010 09:11:50 +0100 Received: (qmail 64767 invoked from network); 9 Sep 2010 08:11:37 -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:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=JlW79Hem1Ssm1Js0rxk5/8UJSpBTv3OeG1waswmHC8hDVtH7a7IM1ygGsU3waZ7zEYlQTT9rFMs3hxpbtLVCx657sOIESkVGSWn+DufojzUNbK7X8wMXc200OOFU+PL7+KkBQ5OPgv4wCsbvgg8Nz1GDl8cQ1yaKj2VtenC1EgI= ; DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=btinternet.com; s=s1024; t=1284019897; bh=IGpcgDAf0ZbFUyuPLf/iqWHNK2JG4gDHiRpEx86KAvg=; h=Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:From:To:References:Subject:Date:MIME-Version:Content-Type:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=vtRfPRv6xHcNgJOQXZWslDYE9XBSKrQNp181zQPV2zYV8I8n94nTGeYqzxpdsBfXGuYkbc7EFjoee12CiCnI+w/skcNbxzPmfJ3eyXyW+5c8Rb40PZ4YLWwajWu1BPqrxwlyx667H85TztzXGVkcYnXgo2B70iWGc9yzDEiFkDk= Received: from IBM7FFA209F07C (c.ashby435@86.171.33.114 with login) by smtp818.mail.ird.yahoo.com with SMTP; 09 Sep 2010 08:11:36 +0000 GMT X-Yahoo-SMTP: .u8e2g.swBByWKjbpA3lR6Fw.2ZEQrJJpVsTSrpXLCffsPaCEMY- X-YMail-OSG: .I.rtFQVM1kPtJAM2iqHVl2Nvkc4lzuZ4.hO0qEwoDbwImo pFj.LUp_rgIT3dLx4q.5Hkwa5HMxtnR1mz66KmU6DYM7jfS4Qj6h3sqZmz9e 2LHg0R22lI4qPNYMoKrNJ9IgN84rrRbluuaWE.jMOq4dAUwIIA6_HeThF5v0 77leKLmVpUSzb7km3xAQVeotpcBjVw.WarmEeRRqnT38qqx.wghENJET98_F 8mIW1.dNI8v7xvyHVrmtSUOBbZ72nmosIkefS X-Yahoo-Newman-Property: ymail-3 Message-ID: <7304C3CD17394F5B81C72D1A36628D0A@IBM7FFA209F07C> From: "Chris" To: References: <4C8686CF.9060100@iup.uni-heidelberg.de> <4C86A124.907@iup.uni-heidelberg.de> Date: Thu, 9 Sep 2010 09:11:38 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5931 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5931 DomainKey-Status: good (testing) X-Spam-Score: 3.4 (+++) X-Spam-Report: autolearn=disabled,FORGED_MUA_OUTLOOK=3.36,HTML_MESSAGE=0.001,UNPARSEABLE_RELAY=0.001 Subject: Re: LF: 137.5kHz WSPR Tuesday evening - reports appreciated Content-Type: multipart/alternative; boundary="----=_NextPart_000_001B_01CB4FFF.02546050" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: *** X-Spam-Status: No, hits=3.0 required=5.0 tests=FORGED_MUA_OUTLOOK, FROM_ENDS_IN_NUMS,HTML_20_30,HTML_FONTCOLOR_UNSAFE,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: mail_rly_antispam_dkim-m217.2 ; domain : btinternet.com DKIM : pass x-aol-sid: 3039400c89ac4c88970411de X-AOL-IP: 193.82.116.20 X-AOL-SPF: domain : blacksheep.org SPF : none ------=_NextPart_000_001B_01CB4FFF.02546050 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Stefan, I thought the power was the RMS voltage squared (i.e. peak voltage X= 0.707) divided by the resistance. Chris, G4AYT. ----- Original Message -----=20 From: Stefan Sch=E4fer=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, September 07, 2010 9:31 PM Subject: Re: LF: 137.5kHz WSPR Tuesday evening - reports appreciated Roger, For measuring the output power take a 50 Ohm dummy load (50, not 55= Ohms or so) and measure the peak voltage with an oscilloscope. Type= this into the excel file and calculate the output power (P=3D(=FB)^2/= (2*R)). 73, Stefan Am 07.09.2010 21:32, schrieb Andy Talbot:=20 Take a look at G3NYK's Class E design page http://www.alan.melia.b= tinternet.co.uk/classepa.htm Don't even try biassing the FET with a pot. You must use a square= wave drive- preferrable from a proper MOSFET driver like an ICL7667 or= TC4426 type, or at a push a stack of paralleled 74C drivers will do.= =20 I measured somewhere between 85 - 103% efficiency for a 20 Watt= design running from 12V on 1.9MHz. Its very difficult to measure PA= efficiency properly at low frequencies as the HP432 power meter does= n't go below 10MHz Judging by how not-hot the device got, looks to= be around 90%. See the next RadCom for more details. Andy www.g4jnt.com On 7 September 2010 20:08, Roger Lapthorn wrote: Stefan/Mal, Clearly my design was not working in class E properly as the PA= was dissipating a fair amount of heat and it was taking about 0.8A to= produce 40V p-p output from a 13.8V supply which is about half as eff= icient as it should be. I took a PA design start from a design program= I found on the net by Tonne Software called "Class E" and the values= seemed to be close to optimum when I adjusted caps and L up and down= a small amount, but the dissipation seems miles off what a good class= E design should take. The IRF510 gate voltage is set just below 3V wi= th a resistive pot. The drive is not a square wave though, so I suppos= e this could be part of the issue? Stefan, if you have a better class E PA circuit for 137kHz suita= ble for around the 10-20W out region I'd be interested in seeing it.= I would prefer to use toroid inductors because of size. I have severa= l T106-2 cores to hand as well as several 16mm diameter 3C90 cores. I'm still learning..... and not too proud to ask for help from= those with more experience. 73s Roger G3XBM 2010/9/7 Stefan Sch=E4fer Hello Roger, Maybe you can send us a circuit with its values. I have built= class E PA for 2200/160/80/40/30/17/10m and have some experience. If= you are using a IRF510 and stay in the QRP range (< 10 W) at 137 in= a class E stage you wouldn't even need a heat sink at all if well dim= ensioned! See the infos at http://www.classeradio.com/ This is most use= ful if you are starting with that design. On 137 kHz problems are much= smaller than on HF :-) Best 73, Stefan/DK7FC Am 07.09.2010 20:17, schrieb Roger Lapthorn:=20 Just hit a bit of a snag and blew up my (last) IRF510 PA bec= ause of totally inadequate heatsink. So, I'm on 137.5kHz WSPR but only= with about 1W from the simpler PA at present, so ERP low uWs. I need= to get some heatsink and more FETs! Any reports (now less likely) still appreciated. [Mal - it started out as a Class E design attempt but hadn't= been optimised, so I guess this counts as class D. ] 73s Roger G3XBM On 7 September 2010 17:34, Roger Lapthorn wrote: My 137.5kHz WSPR TX transverter is now working fine, so I'= ll be on-air with WSPR tonight (Sept 7th) from 5.30pm - 11pm UK time.= =20 After my success on QRSS3 with G3XIZ I'm hopeful he'll now= decode my WSPR signal tonight, assuming Chris can take a listen. If= anyone else within, say, 100km of Burwell, Cambs JO02dg cares to take= a look for the WSPR beacon (running around 35% TX time) I'd be most= grateful.=20 Not sure if anyone else has had this problem, but I was us= ing the small 16mm 3C90 cores (cream colour) as the PA bifilar output= transformer and I had all sorts of issues with the darn thing overhea= ting and even one cracking. I replaced this with a choke wound on a T1= 06-2 core and made the output network work in class D/E and now everyt= hing is working very predictably. The larger diameter 3C90 cores seem= fine in the step-down transformer matching the "in the air" loop. The WSPR beacon is now going ON..... 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 --=20 http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/g3xbm G3XBM GQRP 1678 ISWL G11088 ------=_NextPart_000_001B_01CB4FFF.02546050 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Stefan,
I thought the power was the RMS volta= ge squared=20 (i.e. peak voltage X 0.707) divided by the resistance.
Chris, G4AYT.
----- Original Message -----
Sent: Tuesday, September 07,= 2010 9:31=20 PM
Subject: Re: LF: 137.5kHz WSP= R Tuesday=20 evening - reports appreciated

Roger,

For measuring the output power take a= 50 Ohm=20 dummy load (50, not 55 Ohms or so) and measure the peak voltage with= an=20 oscilloscope. Type this into the excel file and calculate the output= power=20 (P=3D(=FB)^2/(2*R)).

73, Stefan


Am 07.09.2010 21:3= 2, schrieb=20 Andy Talbot:=20
Take a look at G3NYK's Class E design page http://www.alan.melia.btinternet.co.uk/classepa.htm
 
Don't even try biassing the FET with a pot.  You must us= e a=20 squarewave drive- preferrable from a proper MOSFET driver like an= ICL7667 or=20 TC4426 type, or at a push a stack of paralleled 74C drivers= will=20 do. 
 
I measured somewhere between  85 - 103% efficiency&= nbsp;for a=20 20 Watt design running from 12V on 1.9MHz.  Its very difficul= t to=20 measure PA efficiency properly at low frequencies as the HP432&nbs= p; power=20 meter doesn't go below 10MHz    Judging by how not-= hot the=20 device got, looks to be around 90%.    See the next= RadCom=20 for more details.
 
On 7 September 2010 20:08, Roger Lapthorn= <rogerlapthorn@gmail.com>= wrote:
Stefan/Mal,

Clearly my design was not working in=20 class E properly as the PA was dissipating a fair amount of heat= and it=20 was taking about 0.8A to produce 40V p-p output from a 13.8V sup= ply which=20 is about half as efficient as it should be. I took a PA design= start from=20 a design program I found on the net by Tonne Software called "Cl= ass E" and=20 the values seemed to be close to optimum when I adjusted caps an= d L up and=20 down a small amount, but the dissipation seems miles off what a= good class=20 E design should take. The IRF510 gate voltage is set just below= 3V with a=20 resistive pot. The drive is not a square wave though, so I suppo= se this=20 could be part of the issue?

Stefan, if you have a better= class E PA=20 circuit for 137kHz suitable for around the 10-20W out region I'd= be=20 interested in seeing it. I would prefer to use toroid inductors= because of=20 size. I have several T106-2 cores to hand as well as several 16m= m diameter=20 3C90 cores.

I'm still learning..... and not too proud to= ask for=20 help from those with more experience.

73s
Roger=20 G3XBM





2010/9/7 Stefan Sch=E4fer <schaefer@iup.uni-heidelber= g.de>
Hello Roger,

= Maybe you can=20 send us a circuit with its values. I have built class E PA for= =20 2200/160/80/40/30/17/10m and have some experience. If you are= using a=20 IRF510 and stay in the QRP range (< 10 W) at 137 in a class= E stage=20 you wouldn't even need a heat sink at all if well=20 dimensioned!

See the infos at http://www.classeradio.com/  This is=20 most useful if you are starting with that design. On 137 kHz= problems=20 are much smaller than on HF :-)

Best 73, Stefan/DK7FC
Am=20 07.09.2010 20:17, schrieb Roger Lapthorn:=20
Just hit a bit of a snag and blew up= my (last)=20 IRF510 PA because of totally inadequate heatsink. So, I'm on= 137.5kHz=20 WSPR but only with about 1W from the simpler PA at present,= so ERP low=20 uWs.  I need to get some heatsink and more FETs!
Any=20 reports (now less likely) still appreciated.

[Mal -= it started=20 out as a Class E design attempt but hadn't been optimised,= so I guess=20 this counts as class D. ]

73s
Roger G3XBM

<= BR>
On 7 September 2010 17:34, Roger La= pthorn <roger= lapthorn@gmail.com>=20 wrote:
My 137.5kHz WSPR TX transverter is now working= =20 fine, so I'll be on-air with WSPR tonight (Sept 7th)= from=20 5.30pm - 11pm UK time.

After my success on= QRSS3=20 with G3XIZ I'm hopeful he'll now decode my WSPR signal ton= ight,=20 assuming Chris can take a listen. If anyone else within,= say, 100km=20 of Burwell, Cambs JO02dg cares to take a look for the WSPR= beacon=20 (running around 35% TX time) I'd be most grateful.= =20

Not sure if anyone else has had this problem, but= I=20 was using the small 16mm 3C90 cores (cream colour)= as the PA=20 bifilar output transformer and I had all sorts of issues= with the=20 darn thing overheating and even one cracking. I replaced= this with a=20 choke wound on a T106-2 core and made the output network= work in=20 class D/E and now everything is working very predictably.= The larger=20 diameter 3C90 cores seem fine in the step-down transformer= matching=20 the "in the air" loop.

The WSPR beacon is now going= =20 ON.....

73s
Roger G3XBM


--
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/g3xbm
G3X= BM  =20 GQRP 1678    ISWL=20 G11088



= --
http://g3xbm-qrp.blogsp= ot.com/
http://www.g3xbm.co.uk<= /A>
http://www.youtube.com= /user/g3xbm
G3XBM  =20 GQRP 1678    ISWL=20 G11088


--
htt= p://g3xbm-qrp.blogspot.com/
http://www.g= 3xbm.co.uk
http://www.youtube.= com/user/g3xbm
G3XBM  =20 GQRP 1678    ISWL=20 G11088

------=_NextPart_000_001B_01CB4FFF.02546050--