Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dl06.r1000.mx.aol.com (Internet Inbound) with ESMTP id 5AB8B380000ED; Wed, 13 Jun 2012 15:34:15 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1SetIX-0003YP-1x for rs_out_1@blacksheep.org; Wed, 13 Jun 2012 20:32:09 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1SetIV-0003YG-W1 for rsgb_lf_group@blacksheep.org; Wed, 13 Jun 2012 20:32:07 +0100 Received: from smtpout1.wanadoo.co.uk ([80.12.242.29] helo=smtpout.wanadoo.co.uk) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1SetIS-0005Xc-92 for rsgb_lf_group@blacksheep.org; Wed, 13 Jun 2012 20:32:06 +0100 Received: from AGB ([2.26.8.23]) by mwinf5d06 with ME id MvXz1j00e0VovFE03vXzHd; Wed, 13 Jun 2012 21:32:03 +0200 Message-ID: From: "Graham" To: References: <1339438549.67345.YahooMailNeo@web171605.mail.ir2.yahoo.com> <85F124CBD59C48FEB97567F3B69B2AC1@lindavideo> <1339499711.77638.YahooMailNeo@web171605.mail.ir2.yahoo.com> <006a01cd48cb$f2e1aed0$0401a8c0@xphd97xgq27nyf> <1339599103.18960.YahooMailNeo@web171605.mail.ir2.yahoo.com> In-Reply-To: <1339599103.18960.YahooMailNeo@web171605.mail.ir2.yahoo.com> Date: Wed, 13 Jun 2012 20:31:59 +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! (VPS 120613-0, 13/06/2012), Outbound message X-Antivirus-Status: Clean 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: Gosh me too ! A switching valve cct and something that '' maintains circulating current within each resonator. Since the resonator is designed to store high KVA'' lumped delay line .... with a little -E voltage (-100's !) to the grid showing on the cct , any big tube can be used in pulse (modulator) service ..... and with 50% modulation at 15 KHz audio , that was going to be some hi-fi broadcast system , [...] 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 [80.12.242.29 listed in list.dnswl.org] 0.0 HTML_MESSAGE BODY: HTML included in message X-Scan-Signature: c573b52cf8151384d61669dad73b0e81 Subject: Re: LF: RE: Class E etc Content-Type: multipart/alternative; boundary="----=_NextPart_000_0032_01CD49A3.952550C0" 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: 1:2:496660256:93952408 X-AOL-SCOLL-URL_COUNT: 1 x-aol-sid: 3039ac1d4ad44fd8eb3658f8 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_0032_01CD49A3.952550C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Gosh me too ! A switching valve cct and something that '' maintains circulating = current within each resonator. Since the resonator is designed to store = high KVA'' lumped delay line ....=20 with a little -E voltage (-100's !) to the grid showing on the cct = , any big tube can be used in pulse (modulator) service ..... and = with 50% modulation at 15 KHz audio , that was going to be some = hi-fi broadcast system , must be some air defence ww2 / 1950 radar guys about to fill in = the gaps ! ,=20 I think you could use 807 valve Pete , in pulse service , should = do a good job , lots of -Ve grid bias and a ringing drive cct = ....... you could use a old 'valve' pulse generator for = experimentation , or a new one with a (pulse) transformer on the = o/p .but with the valve into grid 'amps' on peaks , the drive ctt = will need to be stable as the load will swing from 10K to .. = 100's ohms at conduction ?=20 asking before tx 'Is this spectrum in use ?' G. From: M0FMT=20 Sent: Wednesday, June 13, 2012 3:51 PM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: RE: Class E etc Well shoot me down with my britches on fire! Mal=20 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. 73 es GL Pete M0FMT IO91UX From: mal hamilton To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, 12 June 2012, 19:48 Subject: Re: LF: RE: Class E etc 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_0032_01CD49A3.952550C0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Gosh  me too !
 
A switching  valve cct and  something  that ''  = maintains circulating current within each resonator. Since the resonator = is=20 designed to store high KVA''  lumped  delay line ....
 
with a  little  -E voltage  (-100's !)  to = the =20 grid showing on the cct , any big tube  can be used in pulse = (modulator)=20 service .....  and  with   50%  = modulation =20 at  15 KHz   audio , that was going to  = be =20 some  hi-fi   broadcast system ,
 
must  be  some  air defence  ww2 / 1950=20  radar guys  about to fill  in the gaps !  ,
 
I  think  you  could use  807 valve  Pete = , in=20 pulse service  , should  do a  good  job , lots = of  -Ve=20 grid bias  and a  ringing  drive  cct ....... = you =20 could  use a  old  'valve'  pulse generator  = for=20 experimentation , or a  new  one  with a  = (pulse) =20 transformer on the  o/p .but  with the  valve into  = grid=20 'amps'  on peaks , the  drive  ctt will  need  = to =20 be  stable  as the  load  will  swing  = from =20 10K  to .. 100's  ohms  at conduction ?
 
asking  before tx 'Is this spectrum in use ?'
 
G.

From: M0FMT
Sent: Wednesday, June 13, 2012 3:51 PM
To: rsgb_lf_group@blacksheep.org= =20
Subject: Re: LF: RE: Class E etc

Well shoot me down with = my=20 britches on fire!
 
Mal
I have just found an article on an enhanced Class C in Tube=20 amplifiers By RCA.
I have heard of higher = efficiency=20 Valve amps but never gave them any time because I thought they used = special=20 valves to achieve the fast response. But apparently not, it relies on a = tuned=20 circuit in the anode and cathode. The cathode LC being set at the third = harmonic=20 of the anode one. By combining the drive wave with the third hamonic you = get a=20 very fast rising pulse type wave at the drive frequency in the PA = tuned=20 circuit as with a class D/E solid state amp. URL is ........ http://nrcdxas.org/articles/b= ta5t/
 
I think the point about = this is=20 that it works OK for fixed frequency TX's like broadcast transmitters = and the=20 like. And probably will work OK for us on LF with such narrow = allocations where=20 we may get away with one set up.
 
Now to see if it is = scalable to=20 lower power video tubes.
 
73 es GL Pete M0FMT = IO91UX
From: mal hamilton=20 <g3kevmal@talktalk.net>
To: rsgb_lf_group@blacksheep.org=20
Sent: Tuesday, 12 = June 2012,=20 19:48
Subject: Re: = LF: RE:=20 Class E etc

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: M0FMT
To: rsgb_lf_group@blacksheep.= org=20
Sent: Tuesday, June 12, 2012 = 11:15=20 AM
Subject: Re: LF: RE: Class E = etc

Hi Ken
 
I believe you=20 can operate some thermionic devices in higher classes than = C but=20 they generally lack the frequency response of a modern FET. I = won't go into=20 figures but = just think=20 about it. The high efficiency output = stage has to=20 operate like a switch it is not actually an amplifier. The faster it = changes=20 state 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=20 very fast rate in-order to generate = a high=20 electromagnetic field at the drive frequency. We are not talking sine = waves=20 here as a scope on the drain will show. Although a scope on the output = side of=20 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=20 use to 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 data from = following=20 the guide lines lines shown on the sites I have posted that will = get you=20 a good TX. If you want a doctorate in theoretical physics to bamboozle you colleagues then that = will=20 detract from the time it takes to build a very interesting high = power,=20 efficient TX design well within anybodies capabilities. The = GW3UEP = design being=20 IMHO a very good (Scalable) example with no RadCom style=20 unobtainium in=20 the components listing.
 
73 es GL=20 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 Pete.
About 40 years ago my integration was = quite=20 good, liked doing 2nd order differential = equations, partial=20 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 PA is probably more like Class = E by=20 default. The reason I like valves is because they are very forgiving = devices=20 unlike semiconductors, also the keep the shack and the cat=20 warm.
 
73s
 
Ken
 
M0KHW
 
From: owner- rsgb_lf_group@blacksheep.org = [mailto: = owner-=20 rsgb_lf_group@blacksheep.org ] On = Behalf Of=20 M0FMT
Sent: 11=20 June 2012 19:16
To: = rsgb_lf_group@blacksheep.org
Subject: LF: Class E=20 etc
 
 
Hi Ken =
 
Ha ha Stefan, how good is your Integration=20 Ken?
 
Here are a couple of sites that should = answer=20 your questions. You need a good dummy load and a good oscilloscope. = Setting=20 the conditions for the amplifier is to do with  A/ the correct = driver=20 preferably using a FET drive chip (like TC4422 non and = TC4421=20 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,=20 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 are capable of = incredibly good=20 efficiency well above a dodgy class C amp. This means the heat = dissipation=20 from the FET=20 is very low at high power giving cool heat-sinks!<= /SPAN>
 
The GW3UEP (do a web search) single ended = design is=20 capable good efficiency&= nbsp;and=20 high power depending upon the FET used and Drain supply voltage. I = have=20 modified one to run reliably at 140watts and is capable of almost = twice that=20 into a dummy load with a heat sink that is fairly cool. Adjusting L = and C=20 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 and search info on = class E=20 amplifiers. 
 
 
For some bed time reading but ignor = the math look=20 at the Tuning Procedure and the pictures at the end which tell it all=20 really..... http://www.cs.berkeley.edu/~culler/AIIT/papers/radio/Soka= l%20AACD5-poweramps.pdf
 
For design = ideas
=
 
For a good practical circuit for a = single ended=20 amp that  is a scalable = surefire=20 design, no need to reinvent the wheel.
 
For antennas and antenna feed methods = a "look no=20 where else site"
http://www.strobbe.eu/on7yd/136ant/
 
73 es GL Pete M0FMT IO91UX
=
<= /DIV>


 


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