Return-Path: Received: from mtain-dg10.r1000.mx.aol.com (mtain-dg10.r1000.mx.aol.com [172.29.65.18]) by air-dc07.mail.aol.com (v129.4) with ESMTP id MAILINDC073-86534c8693b421e; Tue, 07 Sep 2010 15:34:12 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dg10.r1000.mx.aol.com (Internet Inbound) with ESMTP id 75D5538000094; Tue, 7 Sep 2010 15:34:10 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Ot3uL-0002FY-Kp for rs_out_1@blacksheep.org; Tue, 07 Sep 2010 20:32:41 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Ot3uK-0002FP-VI for rsgb_lf_group@blacksheep.org; Tue, 07 Sep 2010 20:32:40 +0100 Received: from mail-iw0-f171.google.com ([209.85.214.171]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Ot3uE-0000i7-Kt for rsgb_lf_group@blacksheep.org; Tue, 07 Sep 2010 20:32:41 +0100 Received: by iwn42 with SMTP id 42so6239336iwn.16 for ; Tue, 07 Sep 2010 12:32:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:content-type; bh=uTY//4lg2JJVQ6lqkkLPcyzBBNlmzup/vnx8C6mzMuY=; b=Ajycc4OzVwzU6W34gKGN9hq/OIO88y/sNktcJYtWcYv7dFqqiks/n0jALHkRcijS3d cIZ6Delh5Ea0QQY9bdwZ8+ZQe4PAvSHDzJk7Fh8lGXIug/ExS4rHwu1Bqa8FFQqkcLke X3zEslzj09fp3z4U48MEME3hMdQZPPZ4SbFFo= DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=DOAOa3gbmon8u9R90PyTCtMtefMfmnYYedKQYZ2z5lBj0vXiejkGcXeMQh8wlBbbCb I91Y6B2tfQx/zU8TF//uQwy1Cj6KV9yMKKkKhtwYRrQHCCuINUH35xYufkQ3b7s5nUEN VMWTFyK/8bKJji730o9SNsIgTbKljLHzDkqXI= MIME-Version: 1.0 Received: by 10.231.185.142 with SMTP id co14mr8108168ibb.97.1283887951220; Tue, 07 Sep 2010 12:32:31 -0700 (PDT) Received: by 10.231.167.149 with HTTP; Tue, 7 Sep 2010 12:32:31 -0700 (PDT) In-Reply-To: References: <4C8686CF.9060100@iup.uni-heidelberg.de> Date: Tue, 7 Sep 2010 20:32:31 +0100 Message-ID: From: Andy Talbot 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: 137.5kHz WSPR Tuesday evening - reports appreciated Content-Type: multipart/alternative; boundary=0016e6d26145438f7e048fb07502 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.1 required=5.0 tests=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-d257.1 ; domain : googlemail.com DKIM : pass x-aol-sid: 3039ac1d41124c8693b27ba0 X-AOL-IP: 193.82.116.20 X-AOL-SPF: domain : blacksheep.org SPF : none X-Mailer: Unknown (No Version) --0016e6d26145438f7e048fb07502 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable 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 use a squarewave 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. 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 doesn'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 produc= e > 40V p-p output from a 13.8V supply which is about half as efficient 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 with a resistive pot. The drive= is > not a square wave though, so I suppose this could be part of the issue? > > Stefan, if you have a better class E PA circuit for 137kHz suitable for > around the 10-20W out region I'd be interested in seeing it. I would pre= fer > to use toroid inductors because of size. I have several 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 wit= h > 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 dimensioned! >> >> See the infos at http://www.classeradio.com/ This is most useful if yo= u >> are starting with that design. On 137 kHz problems are much smaller tha= n on >> HF :-) >> >> Best 73, Stefan/DK7FC >> >> Am 07.09.2010 20:17, schrieb Roger Lapthorn: >> >> Just hit a bit of a snag and blew up my (last) IRF510 PA because of >> totally inadequate heatsink. So, I'm on 137.5kHz WSPR but only with abo= ut 1W >> from the simpler PA at present, so ERP low uWs. I need to get some hea= tsink >> 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 wrot= e: >> >>> My 137.5kHz WSPR TX transverter is now working fine, so I'll be *on-ai= r >>> with WSPR tonight (Sept 7th) from 5.30pm - 11pm UK time*. >>> >>> 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 withi= n, >>> 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. >>> >>> Not sure if anyone else has had this problem, but I *was* using the >>> small 16mm 3C90 cores (cream colour) as the PA bifilar output transfor= mer >>> and I had all sorts of issues with the darn thing overheating and even= one >>> cracking. I replaced this with a choke wound on a T106-2 core and made= the >>> output network work in class D/E and now everything 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 >>> >>> >>> -- >>> 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 >> >> > > > -- > http://g3xbm-qrp.blogspot.com/ > http://www.g3xbm.co.uk > http://www.youtube.com/user/g3xbm > G3XBM GQRP 1678 ISWL G11088 > --0016e6d26145438f7e048fb07502 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
Take a look at G3NYK's Class E design page http://www.alan.melia.btinternet= .co.uk/classepa.htm
=A0
Don't even try biassing the FET with a pot.=A0 You must use a squ= arewave drive- preferrable from a proper MOSFET driver like an ICL7667 or= TC4426 type, or at=A0a push a stack of paralleled 74C drivers will do.=A0=
=A0
I measured somewhere between=A0=A085 - 103% efficiency=A0for a 20 Wat= t design running from 12V on 1.9MHz.=A0 Its very difficult to measure PA= efficiency properly at low frequencies as the HP432=A0 power meter doesn&= #39;t go below 10MHz=A0=A0=A0 Judging by how not-hot the device got, looks= to be around 90%.=A0=A0=A0 See the next RadCom for more details.
=A0
On 7 September 2010 20:08, Roger Lapthorn <rogerlapthorn@= gmail.com> wrote:
Stefan/Mal,

Clearly my= design was not working in class E properly as the PA was dissipating a fa= ir 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 efficient 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 di= ssipation seems miles off what a good class E design should take. The IRF5= 10 gate voltage is set just below 3V with a resistive pot. The drive is no= t a square wave though, so I suppose this could be part of the issue?

Stefan, if you have a better class E PA circuit for 137kHz suitable fo= r 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 several T106-2 cor= es to hand as well as several 16mm diameter 3C90 cores.

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

73s
Roger G3XBM





2010/9/7 Stefan Sch=E4fer <= ;schae= fer@iup.uni-heidelberg.de>
Hello Roger,

Maybe you ca= n 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 st= ay 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 dimensioned!

See the infos at http://www.classeradio.com/=A0 This is most useful if you are sta= rting 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 Laptho= rn:=20
Just hit a bit of a snag and blew up my (last)= IRF510 PA because 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 uW= s.=A0 I need to get some heatsink and more FETs!

Any reports (now less likely) still appreciated.

[Mal - it star= ted out as a Class E design attempt but hadn't been optimised, so I gu= ess this counts as class D. ]

73s
Roger G3XBM



On 7 September 2010 17:34, Roger Lapthorn <rogerlapthorn@gmail.com> 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.

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

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

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

73s
Roger G3XBM


--
http://g3xbm-qrp.blogspot.com/
= http://www.g3xbm.co.= uk
http://www= .youtube.com/user/g3xbm
G3XBM=A0=A0 GQRP 1678=A0=A0=A0 ISWL G11088<= br>



--
http://g3xbm-qrp.blogspot= .com/
http://www.g3xbm.co.= uk
= http://www.youtube.com/user/g3xbm
G3XBM=A0=A0 GQRP 1678=A0=A0=A0 IS= WL G11088



--
http://g3xbm-qr= p.blogspot.com/
http://www.g3xbm.co.uk
http://www= .youtube.com/user/g3xbm
G3XBM=A0=A0 GQRP 1678=A0=A0=A0 ISWL G11088<= br>

--0016e6d26145438f7e048fb07502--