Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-da06.r1000.mx.aol.com (Internet Inbound) with ESMTP id BA07338000097; Wed, 13 Jun 2012 10:52:44 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1SeovF-0002R4-Uq for rs_out_1@blacksheep.org; Wed, 13 Jun 2012 15:51:49 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1SeovE-0002Qv-Ph for rsgb_lf_group@blacksheep.org; Wed, 13 Jun 2012 15:51:48 +0100 Received: from nm20-vm0.bullet.mail.ird.yahoo.com ([77.238.189.221]) by relay1.thorcom.net with smtp (Exim 4.77) (envelope-from ) id 1SeovB-0004RY-7c for rsgb_lf_group@blacksheep.org; Wed, 13 Jun 2012 15:51:47 +0100 Received: from [77.238.189.233] by nm20.bullet.mail.ird.yahoo.com with NNFMP; 13 Jun 2012 14:51:44 -0000 Received: from [212.82.108.239] by tm14.bullet.mail.ird.yahoo.com with NNFMP; 13 Jun 2012 14:51:44 -0000 Received: from [127.0.0.1] by omp1004.mail.ird.yahoo.com with NNFMP; 13 Jun 2012 14:51:44 -0000 X-DKIM-Result: Domain=yahoo.co.uk Result=Good and Known Domain X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 377578.63775.bm@omp1004.mail.ird.yahoo.com Received: (qmail 22804 invoked by uid 60001); 13 Jun 2012 14:51:44 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.co.uk; s=s1024; t=1339599103; bh=1UyjOiYMG8F4GSYHw12rdKjk5nPGOQuP805Jgz6RKtM=; h=X-YMail-OSG:Received:X-Mailer:References:Message-ID:Date:From:Reply-To:Subject:To:MIME-Version:Content-Type; b=0WUZ0K9WtyuLxFgt32a1pyLvCOeXgq+VtGfYmdFxZPmXcMJFsSnG3ry3BfayPNMKnIcvLhqh4ea7jfGmJsePWd7+wFi6FIY7PRNNQT0xiTHmuu3eDTvevY0R3rc5na35tsOfG9Im8t9ojCN8b9F5U01zbgIYeR/KvNh88kFADfo= DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.co.uk; h=X-YMail-OSG:Received:X-Mailer:References:Message-ID:Date:From:Reply-To:Subject:To:MIME-Version:Content-Type; b=EvNz1337mf9dn93LiBVxxLLalnq8QWrrJ9zqyRf5HQ28V/LGVgDvnuqAZgl6ZHStuzHZEUHDwvlNyUGl5lR8ieCjhsnEqrxa8xZ50HzqC4EpPHfXtYQvV5RNBOYzWt8sjaAh+PX5AprjmU1CqBjaP8c/zPjuUHsNUcKEiLLKjvg=; X-YMail-OSG: RYJ3LAgVM1nzXC3tUbOzpKpzGY5RFtLgs.6PVhd0dBWxT80 JG3ZdkgNkMQa.3AyKD5cjVB4V41dEhJI0xVGgzceoN5BJti3r6bweC3rju2t Hkt.d0Rn.nO9m80TD6TV.GsBpVzIQARPRmN.L_7GCJPRJ1BekuVQAnylA.m2 CW1EA5aW3aunmq374ie35pEkdIfVc_5qwHfx4o.gI_feIarJwC9ichAdFN0i xFoZFFcqYe5fGGV8doQKWd0nWWj0x9C_jzEkuKwhcHgMGF0JVi7BEQxE30DD maYRgRn_w6EMW.HddCdLySnej_eMv2sfEJ.3agv.h1b2wA3MEWBZEUFAzyNj txaTSLeESCF5k8bYW3RbF9wXTHyvap2r8s2yVi3xzae1nI.G.ahWGXPSNJAH DqckS2tgE1N1HuGmKRj7Y41f82KhAvoqiBOPT474ZiIzT5xwp3bGMNQDdSSe pi6kIRaYEDk_gwjefvbVNZKw9a33N9i56fsagS7smS2N_c72HROCysednMjG VChPvNvq2HMhYUd97VjMAeAE7t4orPWP9xV8dcgmrVefhaXQge_uCsMqyWcX k6OMavXMEFwusxdZTnY1o3068LsiNVbVpp3gMgExwLpWJLDir130mWDo1k0n 1mkVCf9NsNEiSvEeVVrO8gP6tidrzl7merFL0cBrc1WLIm7Mqd.CMC9pbe.5 Lc8tyw0ZmuzlVzrbAdslLT3Dm9HsZNusdI9klPOkKHJl8ZjQYtQnAHjrk52R G5LsWhgeghQl5OSa720AkXR2yNQpXLdlo7NsJbyt6_XZHQMWP6wA3M2UOAZ1 KscurVEzm.w-- Received: from [86.164.64.131] by web171605.mail.ir2.yahoo.com via HTTP; Wed, 13 Jun 2012 15:51:43 BST X-Mailer: YahooMailWebService/0.8.118.349524 References: <1339438549.67345.YahooMailNeo@web171605.mail.ir2.yahoo.com> <85F124CBD59C48FEB97567F3B69B2AC1@lindavideo> <1339499711.77638.YahooMailNeo@web171605.mail.ir2.yahoo.com> <006a01cd48cb$f2e1aed0$0401a8c0@xphd97xgq27nyf> Message-ID: <1339599103.18960.YahooMailNeo@web171605.mail.ir2.yahoo.com> Date: Wed, 13 Jun 2012 15:51:43 +0100 (BST) From: M0FMT To: "rsgb_lf_group@blacksheep.org" MIME-Version: 1.0 X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Well shoot me down with my britches on fire! Mal I have just found an article on an enhanced Class C in Tube amplifiers By RCA. I have heard of higher efficiency Valve amps but never gave them any time because I thought they used special valves to achieve the fast response. But apparently not, it relies on a tuned circuit in the anode and cathode. The cathode LC being set at the third harmonic of the anode one. By combining the drive wave with the third hamonic you get a very fast rising pulse type wave at the drive frequency in the PA tuned circuit as with a class D/E solid state amp. URL is ........ http://nrcdxas.org/articles/bta5t/ I think the point about this is that it works OK for fixed frequency TX's like broadcast transmitters and the like. And probably will work OK for us on LF with such narrow allocations where we may get away with one set up. Now to see if it is scalable to lower power video tubes. [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [77.238.189.221 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (m0fmt[at]yahoo.co.uk) 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 FSL_FREEMAIL_2 FSL_FREEMAIL_2 0.0 FSL_FREEMAIL_1 FSL_FREEMAIL_1 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: 57c46fc57df9e768804caa43485df2f4 Subject: Re: LF: RE: Class E etc Content-Type: multipart/alternative; boundary="-176341844-131410687-1339599103=:18960" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: ** X-Spam-Status: No, hits=2.7 required=5.0 tests=HTML_50_60, HTML_FONTCOLOR_UNKNOWN,HTML_MESSAGE,OPT_HEADER,TO_ADDRESS_EQ_REAL 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-SCORE: 1:2:488106496:93952408 X-AOL-SCOLL-URL_COUNT: 1 X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-m407.1 ; domain : yahoo.co.uk DKIM : fail x-aol-sid: 3039ac1d404e4fd8a93b6595 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none ---176341844-131410687-1339599103=:18960 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Well shoot me down with my britches on fire!=0A=A0=0AMal =0AI have just fou= nd an article on an enhanced Class C in Tube amplifiers By RCA.=0AI have he= ard of higher efficiency Valve amps but never gave them any time because I = thought they used special valves to achieve the fast response. But apparent= ly not, it relies on a tuned circuit in the anode and cathode. The cathode = LC being set at the third harmonic of the anode one. By combining the drive= wave with the third hamonic you get a very fast rising pulse type=A0wave a= t the drive frequency in the PA tuned circuit as with a class D/E solid sta= te amp. URL is ........ http://nrcdxas.org/articles/bta5t/=0A=A0=0AI think = the point about this is that it works OK for fixed frequency TX's like bro= adcast transmitters and the like. And probably will work OK for us on LF wi= th such narrow allocations where we may get away with one set up.=0A=A0=0AN= ow to see if it is scalable to lower power video tubes.=0A=0A73 es GL Pete = M0FMT IO91UX=0A=0A=0A________________________________=0A From: mal hamilton= =0ATo: rsgb_lf_group@blacksheep.org =0ASent: Tuesda= y, 12 June 2012, 19:48=0ASubject: Re: LF: RE: Class E etc=0A =0A=0APete es= Co =0AThe class C tube amplifer is the nearest you can get to =0Aclass D o= r E and well designed would=A0produce 70% efficiency. =0AThe class D or E i= s not really an amplifier in the =0Aconvential sense it is merely an RF swi= tch at the frequency of interest and the =0Avoltage generated is increased = by a step up transformer with probably 80% to 90% =0Aefficiency if you are = lucky. =0ALike some have said a tube amp is more robust and tolerant =0Aof= mismatch to antenna without smoke. Fets are good but can go bang if one is= =0Anot careful about matching to load. =0AI have some Dentron amps for the= HF bands and they have =0Abeen going for years. =0AFets are probably more = manageable, compact =A0and safer =0Aregarding voltages, beware of tubes wit= h voltages of a few K/volts at high =0Acurrent, like an electric chair!! = =0A73 de mal/g3kev =0A=0A----- Original Message ----- =0A>From: M0FMT =0A= >To: rsgb_lf_group@blacksheep.org =0A>Sent: Tuesday, June 12, 2012 11:15 = AM =0A>Subject: Re: LF: RE: Class E etc =0A>=0A> =0A>Hi Ken =0A>=A0 =0A>I b= elieve you can operate=A0some thermionic devices in higher classes than C= =A0but they generally lack the frequency response of a modern FET. I won't= go into figures but just think about it. The high efficiency output stage = has to operate like a switch it is not actually an amplifier. The faster i= t changes state from fully on with ultra low resistance to fully off (whic= h=A0means a device that will operate=A0well into the=A0VHF)=A0the higher t= he efficiency. If you have a device that is barely rated to say a couple o= f megs its not going to be much good (in terms of what we are talking abou= t)=A0at 500kc/s. Remember you are trying to get the magnetic field in the = inductor to rise and collapse at a very fast rate in-order to generate a = high electromagnetic field at the drive frequency. We are not talking sine = waves here as a scope on the drain will show. Although a scope on the outp= ut side of the drain inductor will show quite a clean looking sine wave. Try it. =0A>=A0 =0A>That chart at the end of that PDF file is very = clever and is the guide=A0I use to bring a PA into optimum performance. = =0A>=A0 =0A>What I was trying to say is that the math is all very well but = if you are trying to make a practical and=A0efficient CW TX for LF then= =A0there is enough empirical data from following the guide lines lines show= n on the sites I have posted=A0that will get you a good TX. If you want a = doctorate in theoretical physics to bamboozle you colleagues then that wil= l detract from the time it takes to build a very interesting high power, e= fficient=A0TX design well within anybodies capabilities.=A0The GW3UEP desi= gn being IMHO a very good (Scalable) example with no=A0RadCom=A0style unob= tainium in the components listing. =0A>=0A>73 es GL Pete M0FMT IO91UX=0A>= =0A>=0A>________________________________=0A>From: Ken =0A>To: rsgb_lf_group@blacksheep.org =0A>Sent: Monday, 11 June 201= 2, 22:09=0A>Subject: LF: RE: Class E etc=0A>=0A>=0A> =0A>Hi Pete. =0A>Ab= out 40 years ago my integration was quite good, liked doing 2nd order diff= erential equations, partial integration and integration by parts, the one = thing I had big problems with was 3 dimensional integration of a point in = free space . =A0=A0Looking at some of the sites my Class C MOSFET PA is pr= obably more like Class E by default. The reason I like valves is because t= hey are very forgiving devices unlike semiconductors, also the keep the sh= ack and the cat warm. =0A>=A0 =0A>73s =0A>=A0 =0A>Ken =0A>=A0 =0A>M0KHW =0A= >=A0 =0A>=0A>________________________________=0A> =0A>From:owner- rsgb_lf_= group@blacksheep.org [mailto: owner- rsgb_lf_group@blacksheep.org ] On Be= half Of M0FMT=0A>Sent: 11 June 2012 19:16=0A>To: rsgb_lf_group@blacksheep.o= rg=0A>Subject: LF: Class E etc =0A>=A0 =0A>=A0Hi Ken =0A>=A0 =0A>Ha ha S= tefan, how good is=A0your Integration Ken? =0A>=A0Here are a couple of si= tes that should answer your questions. You need a good dummy load and a go= od oscilloscope. Setting the conditions for the amplifier is to do with=A0= A/ the correct driver preferably using a FET drive chip (like TC4422 non a= nd TC4421 inverting) that will turn the FET fully=A0on and fully off on e= ach cycle. Very fast rise time with accurate=A0on off timing (mark / space= ). Ensuring the=A0max permitted gate voltage for the FET=A0is not exceeded = otherwise they pop, look out for transients, a diode clamp helps.=A0 B/ Se= tting the shunt capacitance and inductance=A0in the drain=A0circuit can be= done empirically See article below. Then follow it with=A0a=A0low pass fi= lter, although the output wave will be surprisingly clean.=A0Calculating t= he values is difficult as you don't necessarily know all the starting=A0pa= rameters and in any case=A0the result is=A0going to wide of the mark. The = site below will gives some starting values. Best to=20 use 'Scope measurements to set the output conditions. You are looking for= fast, very fast On / Off rise times. Gate drive and understanding the dra= in circuit is the key. These amplifiers are capable of incredibly good ef= ficiency well above a dodgy class C amp. This means the heat dissipation f= rom the FET is very low at high power=A0giving cool heat-sinks! =0A>=A0The= GW3UEP (do a web search) single ended design is capable good efficiency=A0= and high power depending upon the FET used and Drain supply voltage. I ha= ve modified one to run reliably at 140watts and is capable of almost twice= that into a dummy load with a heat sink that is fairly cool. Adjusting L = and C empirically using the 'scope to get the correct drain wave shape for= max efficiency is the way to go. The article below shows you what you are= looking for. I set my TX up into a 50 Ohm dummy load adjusting L and C to= get the correct drain wave shape on the 'scope then measuring the peak vo= ltage across the Dummy load.=A0I then transfer my=A0connector from the Dum= my load to the input of the tuned transformer in the antenna up-lead. I ad= just the coupling link to give the same peak voltage=A0across the tuner li= nk turns. You are not looking for maximum peak just the sames as across th= e dummy load indicating a 50ohm match.=A0This is done by either=A0adding or reducing=A0the number of turns (about two turns) along= with bringing the the transformer to resonance by measuring the peak=A0up= -lead current, here you are looking for the maximum peak.=A0=A0 =0A>=A0 = =0A>Oh yes and WIMA high voltage high value capacitors from Maplin work we= ll. =0A> =0A>=A0Read the articles and search info on class E amplifiers.= =A0 =0A>=A0 =0A>=A0 =0A>For some bed time reading but ignor the math look= at the Tuning Procedure and the pictures at the end which tell it all rea= lly..... http://www.cs.berkeley.edu/~culler/AIIT/papers/radio/Sokal%20AACD5= -poweramps.pdf =0A>=A0 =0A>For design ideas http://www.classeradio.com/ = =0A>=A0 =0A>For a good practical circuit for a single ended amp=A0that =A0= is a scalable surefire design, no need to reinvent the wheel. =0A>http://= www.gw3uep.ukfsn.org/ =0A> =0A>=A0For antennas and antenna feed methods a = "look no where else site" =0A> =0A>http://www.strobbe.eu/on7yd/136ant/ = =0A>=A0 =0A>73 es GL Pete M0FMT IO91UX=0A>=0A>=A0 ---176341844-131410687-1339599103=:18960 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
Well shoot me down with my britches on fire!
&nb= sp;
Mal
I = have just found an article on an enhanced Class C in Tube amplifiers By RCA= .
I have heard of higher ef= ficiency Valve amps but never gave them any time because I thought they use= d special valves to achieve the fast response. But apparently not, it relies on a tu= ned circuit in the anode and cathode. The cathode LC being set at the third= harmonic of the anode one. By combining the drive wave with the third hamo= nic you get a very fast rising=0A pulse type wave at the drive frequen= cy in the PA tuned circuit as with a class D/E solid state amp. URL is ....= .... http://nrcdxas.org/arti= cles/bta5t/
 
I think the point about this is that = it works OK for fixed frequency TX's like broadcast transmitters and the l= ike. And probably will work OK for us on LF with such narrow allocations wh= ere we may get away with one set up.
 
Now to see if it is scal= able to lower power video tubes.
 
73 es GL Pete M0FMT IO91UX
<= font size=3D"2" face=3D"Arial">
From: mal ham= ilton <g3kevmal@talktalk.net>
To: rsgb_lf_group@blacksheep.org
Sent: Tuesday, 12 June 2012, 19:48
Subject: Re: LF: RE: Class E etc

=0A=0A =0A =0A
=0A
Pete es Co
=0A
The class C= tube amplifer is the nearest you can get to =0Aclass D or E and well desig= ned would produce 70% efficiency.
=0A
The class D or E is not really an amplifier in the =0Aconvential sense= it is merely an RF switch at the frequency of interest and the =0Avoltage = generated is increased by a step up transformer with probably 80% to 90% = =0Aefficiency if you are lucky.
=0A
L= ike some have said a tube amp is more robust and tolerant =0Aof mismatch to= antenna without smoke. Fets are good but can go bang if one is =0Anot care= ful about matching to load.
=0A
I have= some Dentron amps for the HF bands and they have =0Abeen going for years.<= /font>
=0A
Fets are probably more manageable,= compact  and safer =0Aregarding voltages, beware of tubes with voltag= es of a few K/volts at high =0Acurrent, like an electric chair!!=0A
73 de mal/g3kev
=0A
 =0A
=0A
----- Original Message -----
=0A
From:= =0A M0F= MT
=0A
To: <= a title=3D"rsgb_lf_group@blacksheep.org" href=3D"mailto:rsgb_lf_group@black= sheep.org" rel=3D"nofollow" target=3D"_blank" ymailto=3D"mailto:rsgb_lf_gro= up@blacksheep.org">rsgb_lf_group@blacksheep.org =0A
=0A
Sent: Tuesday, June 12, 2012 1= 1:15 =0A AM
=0A
Subj= ect: Re: LF: RE: Class E etc
=0A

=0A
=0A
Hi Ken
=0A
 <= /div>=0A
I believe you can =0A operate some thermionic devices in higher cl= asses than C but they =0A generally lack the frequency response of a = modern FET= . I won't go into figures= but just think about it. The high =0A efficiency output stage has to operate = =0A like a switch it is not actually an amplifier. The faster it changes s= tate =0A from fully on with ultra low resistance to fully off (which = means a =0A device that will operate well into the VHF) the= higher the =0A efficiency. If you have a device that is barely rated to s= ay a couple of megs =0A its not going to be much good (in terms of what we= are talking about) at =0A 500kc/s. Remember you are trying to get th= e magnetic field in the inductor to =0A rise and collapse at a very fast =0A rate in-order to generate= a =0A high electromagnetic field at the drive frequency. We are not talki= ng sine =0A waves here as a scope on the drain will show. Although a scope= on the output =0A side of the drain inductor will show quite a clean look= ing sine wave. Try =0A it.
=0A
 
= =0A
That chart at the end of that PDF file is very clever and is t= he guide I use to =0A bring a PA into optimum performance.=0A
 
=0A
What I was trying to s= ay is that the math is all very well but if =0A you are trying to make a p= ractical and efficient CW TX for LF =0A then there is enough empirical =0A data f= rom following the guide lines lines shown on the sites I have =0A posted&n= bsp;that will get you a good TX. If you want a doctorate in =0A theoretica= l physics to bamboozle you =0A colleagues= then that will detract =0A from the time it takes to build a very = interesting high = power, efficient TX =0A design well within anybodies capabilities.&nb= sp;The GW<= /span>3UEP= design being =0A IMHO a very good (Scalable) example with no = RadCom style unobtainium in the components listing.
=0A
&n= bsp;
=0A
73 es GL Pete M0FMT IO91UX
=0A
=0A
=0A
=0A
From: Ken =0A <ken.h.wright@btinternet.c= om>
To: rsgb_lf_grou= p@blacksheep.org =0A
Sent: Monday, 11 June 2012, =0A 22:09
Subject: LF: RE: Class =0A E etc

=0A =
=0A =0A=0A
=0A
=0A
Hi =0A Pete.=
=0A
About 40 years ago my =0A i= ntegration was quite good, liked doing 2nd order differential equa= tions, partial =0A integration and integration by parts, the one thing I h= ad big problems with =0A was 3 dimensional integration of a point in free = space .   Looking =0A at some of the sites my Class C MOSFET =0A= PA is probably more like Class E by default. The reason I like valves is = =0A because they are very forgiving devices unlike semiconductors, also th= e keep =0A the shack and the cat warm.
=0A
=  
=0A
73s
=0A
 
=0A
Ken
=0A
&nb= sp;
=0A
M0KHW
=0A=
 
=0A
= =0A
=0A
=0A
From: owner- =0A rsgb_lf_group@blacksheep.org [mailto: =0A owner- rsgb_lf_= group@blacksheep.org ] On =0A Behalf= Of M0FMT
Sent:<= /b> 11 June 2012 19:16
To:<= /b> =0A rsgb_lf_group@blacksheep.org
Subject: LF: Class E =0A etc
=0A =
 
=0A
= =0A
=0A
=0A
=0A
=0A
=0A =0A
=0A
=0A =0A
=0A
=0A =0A
=0A
 
=0A
=0A
Hi Ken =0A
=0A
=0A
=0A
=0A
 
=0A
=0A
Ha ha Stefan, how =0A good = is your Integration Ken?
=0A
=0A
=0A <= div style=3D"background: white;" class=3D"yiv1949524383MsoNormal"> 
=0A
=0A Here are= a couple =0A of sites that should answer your questions. You need a good = dummy load and a =0A good oscilloscope. Setting the conditions for the amp= lifier is to do =0A with  A/ the correct driver preferably using a FET = drive chip (like TC4422 non and TC4421 inverting) =0A that will turn the <= span id=3D"yiv1949524383misspell-19" class=3D"yiv1949524383mark">FET= fully on =0A and fully off on each cycle. Very fast rise time with a= ccurate on off =0A timing (mark / space). Ensuring the max permi= tted gate voltage for the =0A FET is not exceeded otherwise they =0A = pop, look out for transients, a diode clamp helps.  B/ Setting the shu= nt =0A capacitance and inductance in the drain circuit can be do= ne empirically See =0A article below. Then= follow it with a low pass filter, although the =0A output wave = will be surprisingly =0A clean. Calcu= lating the values is difficult as you don't necessarily know =0A all the s= tarting parameters and in any case the result is going =0A = to wide of the mark. The site below will gives some starting values. Best t= o =0A use 'Scope measurements to =0A set = the output conditions. You are looking for fast, very fast On / Off rise = =0A times. Gate drive and understanding the drain circuit is the =0A key.=
=0A
=0A
=0A
=0A
These amplifiers =0A are = capable of incredibly good efficiency well above a dodgy class C amp. This = =0A means the heat dissipation from the FET =0A is very low at high power&n= bsp;giving cool heat-sinks!
=0A
=0A
<= font color=3D"black" size=3D"2" face=3D"Verdana">
=0A
=0A
 
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The GW3UEP =0A (do a web search) single e= nded design is capable good efficiency&nb= sp;and =0A high power depending upon the FET used =0A and Drain supply volt= age. I have modified one to run reliably at 140watts and =0A is capable of= almost twice that into a dummy load with a heat sink that is =0A fairly c= ool. Adjusting L and C empirically using = =0A the 'scope to get the correct drain wave shape for max efficiency is t= he way =0A to go. The article below shows you what you are looking for. I = set my TX up =0A into a 50 Ohm dummy load adjusting L and C to get the cor= rect drain wave shape =0A on the 'scope then measuring the peak voltage ac= ross the Dummy load. I =0A then transfer my connector from the D= ummy load to the input of the tuned =0A transformer in the antenna up-lead. I adjust =0A the coupling link to give = the same peak voltage across the tuner link =0A turns. You are not lo= oking for maximum peak just the sames as across the dummy =0A load indicat= ing a 50ohm match. This is done by either adding or =0A reducing=  the number of turns (about two turns) along with bringing the =0A th= e transformer to resonance by measuring the peak up= -lead current, =0A here you are looking for the maximum =0A = peak.  
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= Oh yes and WIMA high voltage high value capacitors from =0A Maplin work =0A= well.
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Read the articles =0A and search info on cl= ass E amplifiers. 
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For some bed time =0A = reading but ignor the math look at the =0A Tuning Procedure and the pictures= at the end which tell it all really..... http://www.cs.berkeley.edu/~culler/AIIT/papers/radio/So= kal%20AACD5-poweramps.pdf
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For design =0A ideas
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For a good =0A prac= tical circuit for a single ended amp that  is a scalable surefire =0A design, no need to reinvent the whee= l.
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For antennas and =0A anten= na feed methods a "look no where else site" =0A
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= 73 es GL Pete M0FMT IO91UX
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