Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-ma01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 1EB75380000A6; Tue, 12 Jun 2012 14:50:24 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1SeW8s-0000a9-CM for rs_out_1@blacksheep.org; Tue, 12 Jun 2012 19:48:38 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1SeW8r-0000a0-9j for rsgb_lf_group@blacksheep.org; Tue, 12 Jun 2012 19:48:37 +0100 Received: from out1.ip02ir2.opaltelecom.net ([62.24.128.238]) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1SeW8m-0000Jj-K7 for rsgb_lf_group@blacksheep.org; Tue, 12 Jun 2012 19:48:36 +0100 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AnAGABSO109Ok8sr/2dsb2JhbABFFoIvnRuRFYRAgQiCEwUBAQMCCAEBA0kCHBABAQMFAgEDBwoEAQEKFwEGBxQBBBoGDQkIBgoJCgECAgEBh2wDDwe5SIpFYgsQhXYDiA2FMpJehH2CYIFX X-IronPort-AV: E=Sophos;i="4.77,398,1336345200"; d="scan'208,217";a="395648451" Received: from host-78-147-203-43.as13285.net (HELO xphd97xgq27nyf) ([78.147.203.43]) by out1.ip02ir2.opaltelecom.net with SMTP; 12 Jun 2012 19:48:30 +0100 Message-ID: <006a01cd48cb$f2e1aed0$0401a8c0@xphd97xgq27nyf> From: "mal hamilton" To: References: <1339438549.67345.YahooMailNeo@web171605.mail.ir2.yahoo.com> <85F124CBD59C48FEB97567F3B69B2AC1@lindavideo> <1339499711.77638.YahooMailNeo@web171605.mail.ir2.yahoo.com> Date: Tue, 12 Jun 2012 18:48:22 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 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: Pete es Co The class C tube amplifer is the nearest you can get to class D or E and well designed would produce 70% efficiency. The class D or E is not really an amplifier in the convential sense it is merely an RF switch at the frequency of interest and the voltage generated is increased by a step up transformer with probably 80% to 90% efficiency if you are lucky. Like some have said a tube amp is more robust and tolerant of mismatch to antenna without smoke. Fets are good but can go bang if one is not careful about matching to load. I have some Dentron amps for the HF bands and they have been going for years. Fets are probably more manageable, compact and safer regarding voltages, beware of tubes with voltages of a few K/volts at high current, like an electric chair!! 73 de mal/g3kev [...] 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 [62.24.128.238 listed in list.dnswl.org] 0.0 FSL_XM_419 Old OE version in X-Mailer only seen in 419 spam -0.0 SPF_PASS SPF: sender matches SPF record 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 FSL_UA FSL_UA 0.0 AXB_XMAILER_MIMEOLE_OL_024C2 AXB_XMAILER_MIMEOLE_OL_024C2 X-Scan-Signature: 273334288f972e3b54f080bebb9ff763 Subject: Re: LF: RE: Class E etc Content-Type: multipart/alternative; boundary="----=_NextPart_000_0065_01CD48CB.F0E828C0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.3 required=5.0 tests=HTML_50_60, HTML_FONTCOLOR_UNKNOWN,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-SCORE: 1:2:500569600:93952408 X-AOL-SCOLL-URL_COUNT: 1 x-aol-sid: 3039ac1d60094fd78f705846 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_0065_01CD48CB.F0E828C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Pete es Co The class C tube amplifer is the nearest you can get to class D or E and = well designed would produce 70% efficiency. The class D or E is not really an amplifier in the convential sense it = is merely an RF switch at the frequency of interest and the voltage = generated is increased by a step up transformer with probably 80% to 90% = efficiency if you are lucky.=20 Like some have said a tube amp is more robust and tolerant of mismatch = to antenna without smoke. Fets are good but can go bang if one is not = careful about matching to load. I have some Dentron amps for the HF bands and they have been going for = years. Fets are probably more manageable, compact and safer regarding = voltages, beware of tubes with voltages of a few K/volts at high = current, like an electric chair!! 73 de mal/g3kev ----- Original Message -----=20 From: M0FMT=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, June 12, 2012 11:15 AM 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 =20 ------=_NextPart_000_0065_01CD48CB.F0E828C0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Pete es Co
The class C tube amplifer is the nearest you can = get to=20 class D or E and well designed would produce 70% = efficiency.
The class D or E is not really an amplifier in = the=20 convential sense it is merely an RF switch at the frequency of interest = and the=20 voltage generated is increased by a step up transformer with probably = 80% to 90%=20 efficiency if you are lucky.
Like some have said a tube amp is more robust = and tolerant=20 of mismatch to antenna without smoke. Fets are good but can go bang if = one is=20 not careful about matching to load.
I have some Dentron amps for the HF bands and = they have=20 been going for years.
Fets are probably more manageable, compact =  and safer=20 regarding voltages, beware of tubes with voltages of a few K/volts at = high=20 current, like an electric chair!!
73 de mal/g3kev
 
----- Original Message -----
From:=20 M0FMT
Sent: Tuesday, June 12, 2012 = 11:15=20 AM
Subject: Re: LF: RE: Class E = etc

Hi Ken
 
I believe you can = 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=20 from fully on with ultra low resistance to fully off (which means = a=20 device that will operate well into the VHF) the higher = the=20 efficiency. If you have a device that is barely rated to say a couple = of megs=20 its not going to be much good (in terms of what we are talking = about) at=20 500kc/s. Remember you are trying to get the magnetic field in the = inductor to=20 rise and collapse at a very = fast=20 rate in-order to = generate a=20 high electromagnetic field at the drive frequency. We are not talking = sine=20 waves here as a scope on the drain will show. Although a scope on the = output=20 side of the drain inductor will show quite a clean looking sine wave. = Try=20 it.
 
That chart at the end of that PDF file is very clever and is the guide I = use to=20 bring a PA into optimum performance.
 
What I was trying to say is that the math is all very well = but if=20 you are trying to make a practical and efficient CW TX for LF=20 then there is enough empirical=20 data from following the guide lines lines shown on the sites I have=20 posted that will get you a good TX. If you want a doctorate in=20 theoretical physics to bamboozle you=20 colleagues then that will = detract=20 from the time it takes to build a very interesting high power, = efficient TX=20 design well within anybodies capabilities. The GW3UEP design being=20 IMHO 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=20 E etc

Hi=20 Pete.
About 40 = years ago my=20 integration was quite good, liked doing 2nd order differential equations, partial = integration and integration by parts, the one thing I had big problems = with=20 was 3 dimensional integration of a point in free space . =   Looking=20 at some of the sites my Class C MOSFET=20 PA is probably more like Class E by default. The reason I like valves = is=20 because they are very forgiving devices unlike semiconductors, also = the keep=20 the shack and the cat 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=20 of sites that should answer your questions. You need a good dummy load = and a=20 good oscilloscope. Setting the conditions for the amplifier is to do=20 with  A/ the correct driver preferably using a FET drive chip (like TC4422 non and TC4421 = inverting)=20 that will turn the FET = fully on=20 and fully off on each cycle. Very fast rise time with accurate on = off=20 timing (mark / space). Ensuring the max permitted gate voltage = for the=20 FET is not exceeded = otherwise they=20 pop, look out for transients, a diode clamp helps.  B/ Setting = the shunt=20 capacitance and 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=20 use 'Scope measurements to=20 set the output conditions. You are looking for fast, very fast On / = Off rise=20 times. Gate drive and understanding the drain circuit is the=20 key.
These = amplifiers=20 are capable of incredibly good efficiency well above a dodgy class C = amp. This=20 means the heat dissipation from the FET=20 is very 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=20 is capable of almost twice that into a dummy load with a heat sink = that is=20 fairly cool. Adjusting L and C empirically= using=20 the 'scope to get the correct drain wave shape for max efficiency is = the way=20 to go. The article below shows you what you are looking for. I set my = TX up=20 into a 50 Ohm dummy load adjusting L and C to get the correct drain = wave shape=20 on the 'scope then measuring the peak voltage across the Dummy = load. I=20 then transfer my connector from the Dummy load to the input of = the tuned=20 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=20 the 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/Sokal= %20AACD5-poweramps.pdf
 
For = design=20 ideas
http://www.classeradio.com/
<= /SPAN>
 
For a = good=20 practical 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


 
------=_NextPart_000_0065_01CD48CB.F0E828C0--