Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-de03.r1000.mx.aol.com (Internet Inbound) with ESMTP id 9AEF138000086; Tue, 12 Jun 2012 07:28:18 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1SePFr-0008DV-H7 for rs_out_1@blacksheep.org; Tue, 12 Jun 2012 12:27:23 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1SePFq-0008DM-MK for rsgb_lf_group@blacksheep.org; Tue, 12 Jun 2012 12:27:22 +0100 Received: from smtpout4.wanadoo.co.uk ([80.12.242.68] helo=smtpout.wanadoo.co.uk) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1SePFn-0007C7-3O for rsgb_lf_group@blacksheep.org; Tue, 12 Jun 2012 12:27:21 +0100 Received: from AGB ([2.26.8.114]) by mwinf5d54 with ME id MPTH1j0072Td5zW03PTHf1; Tue, 12 Jun 2012 13:27:18 +0200 Message-ID: <22D0EE9B51934FCCB589509350617092@AGB> From: "Graham" To: References: <1339438549.67345.YahooMailNeo@web171605.mail.ir2.yahoo.com> <85F124CBD59C48FEB97567F3B69B2AC1@lindavideo> <1339499711.77638.YahooMailNeo@web171605.mail.ir2.yahoo.com> In-Reply-To: <1339499711.77638.YahooMailNeo@web171605.mail.ir2.yahoo.com> Date: Tue, 12 Jun 2012 12:27:16 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-Mimeole: Produced By Microsoft MimeOLE V14.0.8117.416 X-Antivirus: avast! 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Content preview: Triggertron and a delay line (lumped) modern spark set hi From: M0FMT Sent: Tuesday, June 12, 2012 12:15 PM To: rsgb_lf_group@blacksheep.org Subject: Re: LF: RE: Class E etc Hi Ken [...] 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 [80.12.242.68 listed in list.dnswl.org] 0.0 HTML_MESSAGE BODY: HTML included in message X-Scan-Signature: cfcc86a3bdfbba3693e29dd7b2240377 Subject: Re: LF: RE: Class E etc Content-Type: multipart/alternative; boundary="----=_NextPart_000_004A_01CD4896.B430E550" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.4 required=5.0 tests=HTML_50_60, HTML_FONTCOLOR_UNKNOWN,HTML_MESSAGE,MISSING_OUTLOOK_NAME 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: 1:2:497577728:93952408 X-AOL-SCOLL-URL_COUNT: 1 x-aol-sid: 3039ac1d40cb4fd727d25d85 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. ------=_NextPart_000_004A_01CD4896.B430E550 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Triggertron and a delay line (lumped) modern spark set hi From: M0FMT=20 Sent: Tuesday, June 12, 2012 12:15 PM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: RE: Class E etc Hi Ken I believe you can operate some thermionic devices in higher classes than = C but 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 it changes state from fully on with ultra low = resistance to fully off (which means a device that will operate well = into the VHF) the higher the efficiency. If you have a device that is = barely rated to say a couple of megs its not going to be much good (in = terms of what we are talking about) at 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 output side of the drain inductor = will show quite a clean looking sine wave. Try it. That chart at the end of that PDF file is very clever and is the guide I = use to bring a PA into optimum performance. What I was trying to say is that the math is all very well but if you = are trying to make a practical and efficient CW TX for LF then there is = enough empirical data from following the guide lines lines shown on the = sites I have posted that will get you a good TX. If you want a doctorate = in theoretical physics to bamboozle you colleagues then that will = detract from the time it takes to build a very interesting high power, = efficient TX design well within anybodies capabilities. The GW3UEP = design being IMHO a very good (Scalable) example with no RadCom style = unobtainium in the components listing. 73 es GL Pete M0FMT IO91UX From: Ken To: rsgb_lf_group@blacksheep.org=20 Sent: Monday, 11 June 2012, 22:09 Subject: LF: RE: Class E etc Hi Pete. About 40 years ago my integration was quite good, liked doing 2nd order = differential 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 . Looking at some of the sites my Class C MOSFET = PA is probably more like Class E by default. The reason I like valves is = because they are very forgiving devices unlike semiconductors, also the = keep the shack and the cat warm. 73s Ken M0KHW From: owner- rsgb_lf_group@blacksheep.org [mailto: owner- = rsgb_lf_group@blacksheep.org ] On Behalf Of M0FMT Sent: 11 June 2012 19:16 To: rsgb_lf_group@blacksheep.org Subject: LF: Class E etc Hi Ken=20 Ha ha Stefan, how good is your Integration Ken? Here are a couple of sites that should answer your questions. You need a = good dummy load and a good oscilloscope. Setting the conditions for the = amplifier is to do with A/ the correct driver preferably using a FET = drive chip (like TC4422 non and TC4421 inverting) that will turn the FET = fully on and fully off on each cycle. Very fast rise time with accurate = on off timing (mark / space). Ensuring the max permitted gate voltage = for the FET is not exceeded otherwise they pop, look out for transients, = a diode clamp helps. B/ Setting the shunt capacitance and inductance in = the drain circuit can be done empirically See article below. Then follow = it with a low pass filter, although the output wave will be surprisingly = clean. Calculating the values is difficult as you don't necessarily know = all the starting parameters and in any case the result is going to wide = of the mark. The site below will gives some starting values. Best to use = 'Scope measurements to set the output conditions. You are looking for = fast, very fast On / Off rise times. Gate drive and understanding the = drain circuit is the key. These amplifiers are capable of incredibly good efficiency well above a = dodgy class C amp. This means the heat dissipation from the FET is very = low at high power giving cool heat-sinks! The GW3UEP (do a web search) single ended design is capable good = efficiency and high power depending upon the FET used and Drain supply = voltage. I have 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 voltage across the Dummy load. I then transfer = my connector from the Dummy load to the input of the tuned transformer = in the antenna up-lead. I adjust the coupling link to give the same peak = voltage across the tuner link turns. You are not looking for maximum = peak just the sames as across the dummy load indicating a 50ohm match. = This is done by either adding or reducing the number of turns (about two = turns) along with bringing the the transformer to resonance by measuring = the peak up-lead current, here you are looking for the maximum peak. =20 Oh yes and WIMA high voltage high value capacitors from Maplin work = well. Read the articles and search info on class E amplifiers.=20 For some bed time reading but ignor the math look at the Tuning = Procedure and the pictures at the end which tell it all really..... = http://www.cs.berkeley.edu/~culler/AIIT/papers/radio/Sokal%20AACD5-powera= mps.pdf For design ideas http://www.classeradio.com/ For a good practical circuit for a single ended amp that is a scalable = surefire design, no need to reinvent the wheel. http://www.gw3uep.ukfsn.org/ For antennas and antenna feed methods a "look no where else site"=20 http://www.strobbe.eu/on7yd/136ant/ 73 es GL Pete M0FMT IO91UX ------=_NextPart_000_004A_01CD4896.B430E550 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Triggertron and a  delay line (lumped) modern  = spark =20 set  hi

From: M0FMT
Sent: Tuesday, June 12, 2012 12:15 PM
Subject: Re: LF: RE: Class E etc

Hi Ken
 
I believe you can=20 operate some thermionic devices in higher classes than C but = they=20 generally lack the frequency response of a modern FET. I won't go into figures but just think about it. The = high=20 efficiency output stage has to = operate=20 like a switch it is not actually an amplifier. The faster it changes = state from=20 fully on with ultra low resistance to fully off (which means a = device that=20 will operate well into the VHF) the higher the = efficiency. If you=20 have a device that is barely rated to say a couple of megs its not going = to be=20 much good (in terms of what we are talking about) at 500kc/s. = Remember you=20 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=20 field at the drive frequency. We are not talking sine waves here as a = scope on=20 the drain will show. Although a scope on the output side of the drain = inductor=20 will show quite a clean looking sine wave. Try it.
 
That chart at the end of that PDF file is very clever and is the guide I use = to bring a=20 PA into optimum performance.
 
What I was trying to say is that the math is all very well = but if you=20 are trying to make a practical and efficient CW TX for LF = then there=20 is enough empirical data from = following=20 the guide lines lines shown on the sites I have posted that will = get you a=20 good TX. If you want a doctorate in theoretical physics to bamboozle you colleagues then that will detract = from the=20 time it takes to build a very interesting high power, = efficient TX=20 design well within anybodies capabilities. The GW3UEP = design being IMHO=20 a very good (Scalable) example with no RadCom style unobtainium in the components listing.
 
73 es GL Pete M0FMT = IO91UX
From: Ken=20 <ken.h.wright@btinternet.com>
To: rsgb_lf_group@blacksheep.org=20
Sent: Monday, 11 = June 2012,=20 22:09
Subject: LF: = RE: Class E=20 etc

Hi=20 Pete.
About 40 = years ago my=20 integration was quite good, liked doing 2nd order differential equations, partial = integration and=20 integration by parts, the one thing I had big problems with was 3 = dimensional=20 integration of a point in free space .   Looking at some of = the sites=20 my Class C MOSFET PA is = probably more=20 like Class E by default. The reason I like valves is because they are = very=20 forgiving devices unlike semiconductors, also the keep the shack and the = cat=20 warm.
 
73s
 
Ken
 
M0KHW
 
From: owner-=20 rsgb_lf_group@blacksheep.org [mailto:=20 owner- rsgb_lf_group@blacksheep.org ] On=20 Behalf Of M0FMT
Sent: 11 June 2012 = 19:16
To:=20 rsgb_lf_group@blacksheep.org
Subject: LF: Class E=20 etc
 
 
Hi Ken=20
 
Ha ha = Stefan, how=20 good is your Integration = Ken?
 
Here are a = couple of=20 sites that should answer your questions. You need a good dummy load and = a good=20 oscilloscope. Setting the conditions for the amplifier is to do = with  A/=20 the correct driver preferably using a FET=20 drive chip (like TC4422 non and TC4421 inverting) that will turn the = FET fully on and fully off on = each cycle.=20 Very fast rise time with accurate on off timing (mark / space). = Ensuring=20 the max permitted gate voltage for the FET is not exceeded otherwise they pop, look = out for=20 transients, a diode clamp helps.  B/ Setting the shunt capacitance = and=20 inductance in the drain circuit can be done empirically= See=20 article below. Then follow it with a low pass filter, although = the=20 output wave will be surprisingly=20 clean. Calculating the values is difficult as you don't necessarily = know=20 all the starting parameters and in any case the result = is going=20 to wide of the mark. The site below will gives some starting values. = Best to use=20 'Scope measurements to set=20 the output conditions. You are looking for fast, very fast On / Off rise = times.=20 Gate drive and understanding the drain circuit is the=20 key.
These = amplifiers are=20 capable of incredibly good efficiency well above a dodgy class C amp. = This means=20 the heat dissipation from the FET is very=20 low at high power giving cool heat-sinks!<= /SPAN>
 
The GW3UEP=20 (do a web search) single ended design is capable good efficiency&= nbsp;and=20 high power depending upon the FET used=20 and Drain supply voltage. I have modified one to run reliably at = 140watts and is=20 capable of almost twice that into a dummy load with a heat sink that is = fairly=20 cool. Adjusting L and C empirically= using=20 the 'scope to get the correct drain wave shape for max efficiency is the = way to=20 go. The article below shows you what you are looking for. I set my TX up = into a=20 50 Ohm dummy load adjusting L and C to get the correct drain wave shape = on the=20 'scope then measuring the peak voltage across the Dummy load. I = then=20 transfer my connector from the Dummy load to the input of the tuned = transformer in the antenna up-lead. I = adjust=20 the coupling link to give the same peak voltage across the tuner = link=20 turns. You are not looking for maximum peak just the sames as across the = dummy=20 load indicating a 50ohm match. This is done by either adding = or=20 reducing the number of turns (about two turns) along with bringing = the the=20 transformer to resonance by measuring the peak up-lead = current,=20 here you are looking for the maximum=20 peak.  
 
Oh yes and = WIMA high voltage high value = capacitors from=20 Maplin work=20 well.
 
Read the = articles=20 and search info on class E = amplifiers. 
 
 
For some = bed time=20 reading but ignor the math = look at the=20 Tuning Procedure and the pictures at the end which tell it all = really..... http://www.cs.berkeley.edu/~culler/AIIT/papers/radio/Soka= l%20AACD5-poweramps.pdf
 
For design = ideas
http://www.classeradio.com/
=
 
For a good = practical=20 circuit for a single ended amp that  is a scalable = surefire=20 design, no need to reinvent the wheel.
http://www.gw3uep.ukfsn.org/
 
For = antennas and=20 antenna feed methods a "look no where else site"=20
http://www.strobbe.eu/on7yd/136ant/
 
73 es = GL Pete M0FMT IO91UX
<= /DIV>

 
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