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Date: Wed, 13 Jun 2012 23:59:15 +0100 (BST)
From: M0FMT <m0fmt@yahoo.co.uk>
To: "rsgb_lf_group@blacksheep.org" <rsgb_lf_group@blacksheep.org>
In-Reply-To: <4FD900B4.7020905@iup.uni-heidelberg.de>
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Subject: Re: LF: RE: Class E etc
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Hi Stefan and Graham=0A=A0=0AThanks for the comments. None of my MF/LF tx.s=
 run more that 160watts although by seriesing a couple of PSUs one with a f=
loating ground I can run about 280Watts o/p from the TX. I don't like serie=
sing the PSUs so only do it during experimenting not on the air. Need to bu=
ild a new=A0high voltage PSU 100V at a good current rating.=A0The rigs are =
FET PA IRF840 etc=A0mostly xtal controlled or xtal mixer type master oscill=
ator (but do have DDS), into a FET driver chip. And set them as described e=
arlier.=0A=A0=0AI have played with High power Audio amps on 136kc/s transfo=
rming the Low impedance to 50 ohms+/- using Ferrite cored transformer to dr=
ive the antenna tuner. Front end currently popped!! Using it for QRSS overn=
ight.Will get it back on soon.=0A=A0=0AMy interest in Valve or Tube TX is a=
 side issue and am not advocating them for serious modern MF/LF work. Howev=
er there is no reason why not.=0A=A0=0AI have made a couple of TUBE QRP rig=
s one for 160/80 about 4/5 watts out Choke modulated AM and CW and FSK. Wor=
ked most of UK on AM on 3.615megs. The second is a copy for 500kc/s was ori=
ginally VFO controlled but now is again xtal mixer vxo. They use 6CL6 video=
 tubes in the PA. The 500kc/s tube tx only runs a watt o/p yet to figure ou=
t why, it should be about 5watts. How=A0ever on my new found Opera4 have=A0=
been reported in PA0 land (on the limit).=0AI have built and still got one =
or two=A0807 PAed rigs for 80m knocking about. Plus a Louis Varney design m=
ade by an unknown amateur in the 1950s and a Codar T5 and a push pull 807 r=
ig on the stocks.... but probably won't get finished. Plus an FL2000B. This=
 to show my thermionic credentials.... hee!=0A=A0=0AFor shear interest I wo=
uld like to try and make a high efficiency TUBE PA but probably won't get a=
round to it. But that 1960s RCA AM BC TX design looks interesting but proba=
bly very dodgy to set up, stability and all. Graham your arc tubes is all v=
ery well but what I have read is that they have a tendency to blow up......=
 and so do FETs ok so no change there then.=0A=A0=0AMy current limitation t=
o power Stefan is lack of a single stable PSU with a couple of KW output. T=
he antenna is now reduce to 35ft up and 128ft top. =0A=A0=0AI don't have a =
good RX for MF/LF what I have are deaf by others standards and this is my m=
ain area of interest at the moment. I have used a TS50 and a TS690s full fi=
lters=A0plus a couple of direct conversion HB=A0RX=A0with active filers and=
 notch.=0AFront ends have gone from dual gate mosfet to straight into the m=
ixer but S/N is still poor evidenced by WSPR and Opera reports I give to ot=
her station who are being received much better elsewhere. If any one can he=
lp me with that then it would make life here on MF/LF=A0a lot better. =0A=
=A0=0AKeep the bands open and may get to work you Stefan now you have 472/9=
....... why the delay in the UK????=0A=A0=0A73 es GL Pete M0FMT IO91UX=0A=
=0A=0A________________________________=0A From: Stefan Sch=E4fer <Stefan.Sc=
haefer@iup.uni-heidelberg.de>=0ATo: rsgb_lf_group@blacksheep.org =0ASent: W=
ednesday, 13 June 2012, 22:05=0ASubject: Re: LF: RE: Class E etc=0A  =0A=0A=
Hi Pete, LF, =0A=0AOn 137 kHz or 500 kHz you can quite easy achieve 95% eff=
iciency with a=0Aclass E PA. BTW a ferrite transformer is not needed! So if=
 your antenna=0Aprovides stable resonance and impdedance and if you like to=
 play=0Aarround a bit to obtain the best efficiency (not the highes output=
=0Apower), a well designed class E PA is definitifely a good choice! 1 kW=
=0ARF (CW, key down!) is possible with a single IRFP MOSFET. =0AI hardly ex=
pect that you will get such an efficiency with a tube amp=0Abut i can under=
stand the fascination of a glowing tube in a dark shack,=0Aalthough i'm not=
 from the tube generation ;-) The first power amplifier=0Ai heard of was a =
2N3055 in the late 80s as i was 12 year old or so :-)=0A=0A73, Stefan/DK7FC=
=0A=0A=0AAm 13.06.2012 16:51, schrieb M0FMT: =0AWell shoot me down=0Awith m=
y britches on fire! =0A>=A0 =0A>Mal  =0A>I have just found an article on an=
 enhanced Class C in=0ATube amplifiers By RCA. =0A>I have heard of higher=
=0Aefficiency Valve amps but never gave them any time because I thought=0At=
hey used special valves to achieve the fast response. But apparently=0Anot,=
 it relies on a tuned circuit in the anode and cathode. The cathode=0ALC be=
ing set at the third harmonic of the anode one. By combining the=0Adrive wa=
ve with the third hamonic you get a very fast rising pulse=0Atype=A0wave at=
 the drive frequency in the PA tuned circuit as with a=0Aclass D/E solid st=
ate amp. URL is ........ http://nrcdxas.org/articles/bta5t/ =0A>=A0 =0A>I t=
hink the point=0Aabout this is that it works OK for fixed frequency TX's li=
ke broadcast=0Atransmitters and the like. And probably will work OK for us =
on LF with=0Asuch narrow allocations where we may get away with one set up.=
 =0A>=A0 =0A>Now to see if it is=0Ascalable to lower power video tubes. =0A=
>=0A>73 es GL Pete=0AM0FMT IO91UX=0A>=0A>From: mal hamilton <g3kevmal@talkt=
alk.net>=0A>To: rsgb_lf_group@blacksheep.org =0A>Sent: Tuesday, 12 June=0A2=
012, 19:48=0A>Subject: Re: LF: RE:=0AClass E etc=0A>  =0A>=0A>Pete es Co =
=0A>The class C tube amplifer is the nearest you=0Acan get to class D or E =
and well designed would=A0produce 70% efficiency. =0A>The class D or E is n=
ot really an amplifier=0Ain the convential sense it is merely an RF switch =
at the frequency of=0Ainterest and the voltage generated is increased by a =
step up=0Atransformer with probably 80% to 90% efficiency if you are lucky.=
  =0A>Like some have said a tube amp is more robust=0Aand tolerant of misma=
tch to antenna without smoke. Fets are good but=0Acan go bang if one is not=
 careful about matching to load. =0A>I have some Dentron amps for the HF ba=
nds and=0Athey have been going for years. =0A>Fets are probably more manage=
able, compact=0A=A0and safer regarding voltages, beware of tubes with volta=
ges of a few=0AK/volts at high current, like an electric chair!! =0A>73 de =
mal/g3kev =0A>=0A>----- Original Message -----  =0A>>From: M0FMT  =0A>>To: =
rsgb_lf_group@blacksheep.org  =0A>>Sent: Tuesday, June 12, 2012=0A11:15 AM =
=0A>>Subject: Re: LF: RE: Class E etc =0A>>=0A>> =0A>>Hi Ken =0A>>=A0 =0A>>=
I believe you can operate=A0some thermionic devices in higher classes than =
C=A0but=0Athey generally lack the frequency response of a modern FET. I=0Aw=
on't go into figures but just think about it. The high efficiency output st=
age has to operate like a switch it is not actually an=0Aamplifier. The fas=
ter it changes state from fully on with ultra low=0Aresistance to fully off=
 (which=A0means a device that will operate=A0well=0Ainto the=A0VHF)=A0the h=
igher the efficiency. If you have a device that is=0Abarely rated to say a =
couple of megs its not going to be much good (in=0Aterms of what we are tal=
king about)=A0at 500kc/s. Remember you are trying=0Ato get the magnetic fie=
ld in the inductor to rise and collapse at a very=0Afast rate in-order to g=
enerate a high electromagnetic field at the drive frequency. We are=0Anot t=
alking sine waves here as a scope on the drain will show. Although=0Aa scop=
e on the output side of the drain inductor will show quite a=0Aclean lookin=
g sine wave. Try it. =0A>>=A0 =0A>>That chart at the end of that PDF file=
=0Ais very clever and is the guide=A0I use to bring a PA into optimum=0Aper=
formance. =0A>>=A0 =0A>>What I was trying to say is that the math is all ve=
ry=0Awell but if you are trying to make a practical and=A0efficient CW TX f=
or=0ALF then=A0there is enough empirical data from following the guide line=
s lines shown on the sites I have=0Aposted=A0that will get you a good TX. I=
f you want a doctorate in=0Atheoretical physics to bamboozle you colleagues=
 then that will detract from the time it takes to build a very interesting =
high=0Apower, efficient=A0TX design well within anybodies capabilities.=A0T=
he GW3UEP design being IMHO a very good (Scalable) example with no=A0RadCom=
=A0style unobtainium in the components listing. =0A>>=0A>>73 es GL Pete M0F=
MT IO91UX=0A>>=0A>>From: Ken <ken.h.wright@btinternet.com>=0A>>To: rsgb_lf_=
group@blacksheep.org =0A>>Sent: Monday, 11=0AJune 2012, 22:09=0A>>Subject: =
LF: RE:=0AClass E etc=0A>> =0A>>=0A>> =0A>>Hi Pete. =0A>>About 40 years ago=
 my integration was=0Aquite good, liked doing 2nd order differential=0Aequa=
tions, partial integration and integration by parts, the one thing=0AI had =
big problems with was 3 dimensional integration of a point in=0Afree space =
. =A0=A0Looking at some of the sites my Class C MOSFET PA is probably more =
like Class E by default. The reason I like valves=0Ais because they are ver=
y forgiving devices unlike semiconductors, also=0Athe keep the shack and th=
e cat warm. =0A>>=A0 =0A>>73s =0A>>=A0 =0A>>Ken =0A>>=A0 =0A>>M0KHW =0A>>=
=A0 =0A>> =0A>>From:owner- rsgb_lf_group@blacksheep.org [mailto:=0Aowner- r=
sgb_lf_group@blacksheep.org ] On Behalf Of M0FMT=0A>>Sent: 11 June 2012=0A1=
9:16=0A>>To: rsgb_lf_group@blacksheep.org=0A>>Subject: LF: Class E=0Aetc  =
=0A>>=A0 =0A>>=A0  Hi Ken     =0A>>=A0  =0A>>Ha ha Stefan, how good is=A0yo=
ur Integration Ken?   =0A>>=A0  Here are a couple of sites that should=0Aan=
swer your questions. You need a good dummy load and a good=0Aoscilloscope. =
Setting the conditions for the amplifier is to do with=A0=0AA/ the correct =
driver preferably using a FET drive chip (like TC4422 non and TC4421 invert=
ing) that will turn the FET fully=A0on and fully off on each cycle. Very fa=
st rise time with=0Aaccurate=A0on off timing (mark / space). Ensuring the=
=A0max permitted gate=0Avoltage for the FET=A0is not exceeded otherwise the=
y=0Apop, look out for transients, a diode clamp helps.=A0 B/ Setting the=0A=
shunt capacitance and inductance=A0in the drain=A0circuit can be done empir=
ically See article below. Then follow it with=A0a=A0low pass filter, althou=
gh the=0Aoutput wave will be surprisingly clean.=A0Calculating the values i=
s difficult as you don't necessarily=0Aknow all the starting=A0parameters a=
nd in any case=A0the result is=A0going to=0Awide of the mark. The site belo=
w will gives some starting values. Best=0Ato use 'Scope measurements to set=
 the output conditions. You are looking for fast, very fast On /=0AOff rise=
 times. Gate drive and understanding the drain circuit is the=0Akey.    The=
se amplifiers are capable of=0Aincredibly good efficiency well above a dodg=
y class C amp. This means=0Athe heat dissipation from the FET is very low a=
t high power=A0giving=0Acool heat-sinks!     =0A>>=A0  The GW3UEP (do=0Aa w=
eb search) single ended design is capable good efficiency=A0and=0Ahigh powe=
r depending upon the FET used and Drain supply voltage. I=0Ahave modified o=
ne to run reliably at 140watts and is capable of almost=0Atwice that into a=
 dummy load with a heat sink that is fairly cool.=0AAdjusting L and C empir=
ically using the 'scope to get the correct drain wave shape for max efficie=
ncy=0Ais the way to go. The article below shows you what you are looking fo=
r.=0AI set my TX up into a 50 Ohm dummy load adjusting L and C to get the=
=0Acorrect drain wave shape on the 'scope then measuring the peak voltage=
=0Aacross the Dummy load.=A0I then transfer my=A0connector from the Dummy l=
oad=0Ato the input of the tuned transformer in the antenna up-lead.=0AI adj=
ust the coupling link to give the same peak voltage=A0across the=0Atuner li=
nk turns. You are not looking for maximum peak just the sames=0Aas across t=
he dummy load indicating a 50ohm match.=A0This is done by=0Aeither=A0adding=
 or reducing=A0the number of turns (about two turns) along=0Awith bringing =
the the transformer to resonance by measuring the peak=A0up-lead current, h=
ere you are looking for the maximum peak.=A0=A0    =0A>>=A0  =0A>>Oh yes an=
d WIMA high voltage high value capacitors from Maplin work well.  =0A>> =0A=
>>=A0  Read the articles and search info on=0Aclass 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=0Atell it all really=
..... http://www.cs.berkeley.edu/~culler/AIIT/papers/radio/Sokal%20AACD5-po=
weramps.pdf  =0A>>=A0  =0A>>For design ideas   http://www.classeradio.com/ =
    =0A>>=A0  =0A>>For a good practical circuit for a=0Asingle ended amp=A0=
that =A0is a scalable surefire design, no need to reinvent the wheel.   =0A=
>>http://www.gw3uep.ukfsn.org/  =0A>> =0A>>=A0  For antennas and antenna fe=
ed methods=0Aa "look no where else site"     =0A>> =0A>>http://www.strobbe.=
eu/on7yd/136ant/  =0A>>=A0  =0A>>73 es GL Pete=0AM0FMT IO91UX              =
    =0A>>=0A>>=A0       =0A>=0A>         
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<html><body><div style=3D"color:#000; background-color:#fff; font-family:ve=
rdana, helvetica, sans-serif;font-size:10pt"><div><span>Hi Stefan and Graha=
m</span></div><div><span></span>&nbsp;</div><div><span>Thanks for the comme=
nts. None of my <span id=3D"misspell-0" class=3D"mark">MF</span>/LF <span i=
d=3D"misspell-2" class=3D"mark">tx</span>.s run more that 160watts although=
 by <span id=3D"misspell-3" class=3D"mark">seriesing</span> a couple of <sp=
an id=3D"misspell-4" class=3D"mark">PSUs</span> one with a floating ground =
I can run about 280Watts o/p from the TX. I don't like <span id=3D"misspell=
-5" class=3D"mark">seriesing</span> the <span id=3D"misspell-6" class=3D"ma=
rk">PSUs</span> so only do it during experimenting not on the air. Need to =
build a new&nbsp;high voltage <span id=3D"misspell-7" class=3D"mark">PSU</s=
pan> 100V at a good current rating.&nbsp;The rigs are <span id=3D"misspell-=
8" class=3D"mark">FET</span> PA <span id=3D"misspell-9" class=3D"mark">IRF<=
/span>840 etc&nbsp;mostly <span
 id=3D"misspell-10" class=3D"mark">xtal</span> controlled or <span id=3D"mi=
sspell-11" class=3D"mark">xtal</span> mixer type master oscillator (but do =
have DDS), into a <span id=3D"misspell-12" class=3D"mark">FET</span> driver=
 chip. And set them as described earlier.</span></div><div><span></span>&nb=
sp;</div><div><span>I have played with High power Audio amps on 136kc/s tra=
nsforming the Low impedance to 50 ohms+/- using Ferrite cored transformer t=
o drive the antenna tuner. Front end currently <span id=3D"misspell-13"><sp=
an>popped</span></span>!! Using it for <span id=3D"misspell-14" class=3D"ma=
rk">QRSS</span> overnight.Will get it back on soon.</span></div><div><span>=
</span>&nbsp;</div><div><span>My interest in Valve or Tube TX is a side iss=
ue and am not advocating them for serious modern <span id=3D"misspell-15" c=
lass=3D"mark">MF</span>/LF work. However there is no reason why not.</span>=
</div><div><span></span>&nbsp;</div><div><span>I have made a couple of TUBE=
 <span
 id=3D"misspell-17" class=3D"mark">QRP</span> rigs one for 160/80 about 4/5=
 watts out Choke modulated AM and CW and <span id=3D"misspell-18" class=3D"=
mark">FSK</span>. Worked most of UK on AM on 3.615megs. The second is a cop=
y for 500kc/s was originally <span id=3D"misspell-19" class=3D"mark">VFO</s=
pan> controlled but now is again <span id=3D"misspell-20" class=3D"mark">xt=
al</span> mixer <span id=3D"misspell-21" class=3D"mark">vxo</span>. They us=
e 6CL6 video tubes in the PA. The 500kc/s tube <span id=3D"misspell-22" cla=
ss=3D"mark">tx</span> only runs a watt o/p yet to figure out why, it should=
 be about 5watts. How&nbsp;ever on my new found Opera4 have&nbsp;been repor=
ted in PA0 land (on the limit).</span></div><div><span>I have built and sti=
ll got one or two&nbsp;807 <span id=3D"misspell-23" class=3D"mark">PAed</sp=
an> rigs for 80m knocking about. Plus a Louis <span id=3D"misspell-24" clas=
s=3D"mark">Varney</span> design made by an unknown amateur in the 1950s and=
 a <span id=3D"misspell-25"
 class=3D"mark">Codar</span> T5 and a push pull 807 rig on the stocks.... b=
ut probably won't get finished. Plus an FL2000B. This to show my thermionic=
 credentials.... <span id=3D"misspell-26" class=3D"mark">hee</span>!</span>=
</div><div><span></span>&nbsp;</div><div><span>For shear interest I would l=
ike to try and make a high efficiency TUBE PA but probably won't get around=
 to it. But that 1960s RCA AM BC TX design looks interesting but probably v=
ery dodgy to set up, stability and all. Graham your arc tubes is all very w=
ell but what I have read is that they have a tendency to blow up...... and =
so do <span id=3D"misspell-27" class=3D"mark">FETs</span> <span id=3D"missp=
ell-28" class=3D"mark">ok</span> so no change there then.</span></div><div>=
<span></span>&nbsp;</div><div><span>My current limitation to power Stefan i=
s lack of a single stable <span id=3D"misspell-29" class=3D"mark">PSU</span=
> with a couple of KW output. The antenna is now reduce to 35ft up and 128f=
t top.
 </span></div><div><span></span>&nbsp;</div><div><span>I don't have a good =
RX for <span id=3D"misspell-30" class=3D"mark">MF</span>/LF what I have are=
 deaf by others standards and this is my main area of interest at the momen=
t. I have used a TS50 and a TS690s full filters&nbsp;plus a couple of direc=
t conversion <span id=3D"misspell-32" class=3D"mark">HB</span>&nbsp;RX&nbsp=
;with active filers and notch.</span></div><div><span>Front ends have gone =
from dual gate <span id=3D"misspell-33" class=3D"mark">mosfet</span> to str=
aight into the mixer but S/N is still <span id=3D"misspell-34">poor</span> =
evidenced by <span id=3D"misspell-35" class=3D"mark">WSPR</span> and Opera =
reports I give to other station who are being <span id=3D"misspell-36"><spa=
n>received</span></span> much better elsewhere. If any one can help me with=
 that then it would make life here on <span id=3D"misspell-37" class=3D"mar=
k">MF</span>/LF&nbsp;a lot better.
 </span></div><div><span></span>&nbsp;</div><div><span></span><span></span>=
<span></span><span></span><span>Keep the bands open and may get to work you=
 Stefan now you have 472/9.......<var id=3D"yui-ie-cursor"></var> why the d=
elay in the UK????</span></div><div><span></span>&nbsp;</div><div>73 es <sp=
an id=3D"misspell-39" class=3D"mark">GL</span> Pete M0FMT IO91<span id=3D"m=
isspell-41" class=3D"mark">UX</span><br>  <div style=3D"font-family: verdan=
a, helvetica, sans-serif; font-size: 10pt;"> <div style=3D"font-family: tim=
es new roman, new york, times, serif; font-size: 12pt;"> <div dir=3D"ltr"> =
<font size=3D"2" face=3D"Arial"> <div style=3D"margin: 5px 0px; padding: 0p=
x; border: 1px solid rgb(204, 204, 204); height: 0px; line-height: 0; font-=
size: 0px;" class=3D"hr" contentEditable=3D"false" readonly=3D"true"></div>=
  <b><span style=3D"font-weight: bold;">From:</span></b> Stefan <span id=3D=
"misspell-42" class=3D"mark">Sch=E4fer</span> &lt;Stefan.Schaefer@iup.uni-h=
eidelberg.de&gt;<br>
 <b><span style=3D"font-weight: bold;">To:</span></b> rsgb_lf_group@blacksh=
eep.org <br> <b><span style=3D"font-weight: bold;">Sent:</span></b> Wednesd=
ay, 13 June 2012, 22:05<br> <b><span style=3D"font-weight: bold;">Subject:<=
/span></b> Re: LF: RE: Class E etc<br> </font> </div> <br><div id=3D"yiv486=
436119">=0A=0A=0A=0A  =0A=0A<div>=0AHi Pete, LF, <br>=0A<br>=0AOn 137 kHz o=
r 500 kHz you can quite easy achieve 95% efficiency with a=0Aclass E PA. BT=
W a ferrite transformer is not needed! So if your antenna=0Aprovides stable=
 resonance and <span id=3D"misspell-45" class=3D"mark">impdedance</span> an=
d if you like to play=0A<span id=3D"misspell-46" class=3D"mark">arround</sp=
an> a bit to obtain the best efficiency (not the <span id=3D"misspell-47" c=
lass=3D"mark">highes</span> output=0Apower), a well designed class E PA is =
<span id=3D"misspell-48" class=3D"mark">definitifely</span> a good choice! =
1 kW=0ARF (CW, key down!) is possible with a single <span id=3D"misspell-49=
" class=3D"mark">IRFP</span> <span id=3D"misspell-50" class=3D"mark">MOSFET=
</span>. <br>=0AI hardly expect that you will get such an efficiency with a=
 tube amp=0Abut i can understand the fascination of a glowing tube in a dar=
k shack,=0Aalthough <span id=3D"misspell-51" class=3D"mark">i'm</span> not =
from the tube generation ;-) The first power amplifier=0Ai heard of was a 2=
N3055 in the late 80s as i was 12 year old or so :-)<br>=0A<br>=0A73, Stefa=
n/<span id=3D"misspell-52" class=3D"mark">DK</span>7<span id=3D"misspell-53=
" class=3D"mark">FC</span><br>=0A<br>=0A<br>=0AAm 13.06.2012 16:51, <span i=
d=3D"misspell-54" class=3D"mark">schrieb</span> M0FMT:=0A<blockquote type=
=3D"cite">=0A  <div style=3D"color: rgb(0, 0, 0); font-family: verdana, hel=
vetica, sans-serif; font-size: 10pt; background-color: rgb(255, 255, 255);"=
>=0A  <div id=3D"yiv486436119">=0A  <div>=0A  <div style=3D"color: rgb(0, 0=
, 0); font-family: verdana, helvetica, sans-serif; font-size: 10pt; backgro=
und-color: rgb(255, 255, 255);">=0A  <div id=3D"yiv486436119yui_3_2_0_20_13=
3959793478443"><span id=3D"yiv486436119yui_3_2_0_20_1339597934784223">Well =
shoot me down=0Awith my britches on fire!</span></div>=0A  <div><span id=3D=
"yiv486436119yui_3_2_0_20_1339597934784230"></span>&nbsp;</div>=0A  <div id=
=3D"yiv486436119yui_3_2_0_20_1339597934784237"><span id=3D"yiv486436119yui_=
3_2_0_20_1339597934784233">Mal </span></div>=0A  <div><span>I have just fou=
nd an article on an enhanced Class C in=0ATube amplifiers By RCA.</span></d=
iv>=0A  <div id=3D"yiv486436119yui_3_2_0_20_1339597934784245"><span id=3D"y=
iv486436119yui_3_2_0_20_1339597934784239">I have heard of higher=0Aefficien=
cy Valve amps but never gave them any time because I thought=0Athey used sp=
ecial valves to achieve the fast response. But apparently=0Anot, it relies =
on a tuned circuit in the anode and cathode. The cathode=0ALC being set at =
the third harmonic of the anode one. By combining the=0Adrive wave with the=
 third <span id=3D"misspell-56" class=3D"mark">hamonic</span> you get a ver=
y fast rising pulse=0Atype&nbsp;wave at the drive frequency in the PA tuned=
 circuit as with a=0Aclass D/E solid state amp. URL is ........ <a href=3D"=
http://nrcdxas.org/articles/bta5t/" rel=3D"nofollow" target=3D"_blank">http=
://nrcdxas.org/articles/bta5t/</a></span></div>=0A  <div id=3D"yiv486436119=
yui_3_2_0_20_1339597934784278"><span id=3D"yiv486436119yui_3_2_0_20_1339597=
934784277"><span id=3D"yiv486436119yui_3_2_0_20_1339597934784263"></span></=
span>&nbsp;</div>=0A  <div id=3D"yiv486436119yui_3_2_0_20_1339597934784284"=
><span><span id=3D"yiv486436119yui_3_2_0_20_1339597934784286">I think the p=
oint=0Aabout this is that it works OK for fixed frequency <span id=3D"missp=
ell-57" class=3D"mark">TX's</span> like broadcast=0Atransmitters and the li=
ke. And probably will work OK for us on LF with=0Asuch narrow allocations w=
here we may get away with one set up.</span></span></div>=0A  <div id=3D"yi=
v486436119yui_3_2_0_20_1339597934784258"><span id=3D"yiv486436119yui_3_2_0_=
20_1339597934784254"></span>&nbsp;</div>=0A  <div id=3D"yiv486436119yui_3_2=
_0_20_1339597934784296"><span id=3D"yiv486436119yui_3_2_0_20_13395979347842=
90">Now to see if it is=0Ascalable to lower power video tubes.</span></div>=
=0A  <div id=3D"yiv486436119yui_3_2_0_20_1339597934784270">&nbsp;</div>=0A =
 <div id=3D"yiv486436119yui_3_2_0_20_133959793478455">73 es <span id=3D"mis=
spell-59" class=3D"mark">GL</span> Pete=0AM0FMT IO91<span id=3D"misspell-61=
" class=3D"mark">UX</span><br>=0A  <div style=3D"font-family: verdana, helv=
etica, sans-serif; font-size: 10pt;" class=3D"yiv486436119ms__id4273">=0A  =
<div style=3D"font-family: times new roman, new york, times, serif; font-si=
ze: 12pt;" class=3D"yiv486436119ms__id4274">=0A  <div dir=3D"ltr"> <font si=
ze=3D"2" face=3D"Arial"> <b><span style=3D"font-weight: bold;">From:</span>=
</b> <span id=3D"misspell-62" class=3D"mark">mal</span> <span id=3D"misspel=
l-63" class=3D"mark">hamilton</span>=0A<a class=3D"yiv486436119moz-txt-link=
-rfc2396E" href=3D"mailto:g3kevmal@talktalk.net" rel=3D"nofollow" target=3D=
"_blank" ymailto=3D"mailto:g3kevmal@talktalk.net">&lt;g3kevmal@talktalk.net=
&gt;</a><br>=0A  <b><span style=3D"font-weight: bold;">To:</span></b>=0A<a =
class=3D"yiv486436119moz-txt-link-abbreviated" href=3D"mailto:rsgb_lf_group=
@blacksheep.org" rel=3D"nofollow" target=3D"_blank" ymailto=3D"mailto:rsgb_=
lf_group@blacksheep.org">rsgb_lf_group@blacksheep.org</a> <br>=0A  <b><span=
 style=3D"font-weight: bold;">Sent:</span></b> Tuesday, 12 June=0A2012, 19:=
48<br>=0A  <b><span style=3D"font-weight: bold;">Subject:</span></b> Re: LF=
: RE:=0AClass E etc<br>=0A  </font> </div>=0A  <br>=0A  <div id=3D"yiv48643=
6119">=0A  <div>=0A  <div><font face=3D"Arial">Pete es Co</font></div>=0A  =
<div><font face=3D"Arial">The class C tube <span id=3D"misspell-65" class=
=3D"mark">amplifer</span> is the nearest you=0Acan get to class D or E and =
well designed would&nbsp;produce 70% efficiency.</font></div>=0A  <div><fon=
t face=3D"Arial">The class D or E is not really an amplifier=0Ain the <span=
 id=3D"misspell-66" class=3D"mark">convential</span> sense it is merely an =
RF switch at the frequency of=0Ainterest and the voltage generated is incre=
ased by a step up=0Atransformer with probably 80% to 90% efficiency if you =
are lucky. </font></div>=0A  <div><font face=3D"Arial">Like some have said =
a tube amp is more robust=0Aand tolerant of mismatch to antenna without smo=
ke. <span id=3D"misspell-67" class=3D"mark">Fets</span> are good but=0Acan =
go bang if one is not careful about matching to load.</font></div>=0A  <div=
><font face=3D"Arial">I have some <span id=3D"misspell-68" class=3D"mark">D=
entron</span> amps for the HF bands and=0Athey have been going for years.</=
font></div>=0A  <div><font face=3D"Arial"><span id=3D"misspell-69" class=3D=
"mark">Fets</span> are probably more manageable, compact=0A&nbsp;and safer =
regarding voltages, beware of tubes with voltages of a few=0AK/volts at hig=
h current, like an electric chair!!</font></div>=0A  <div><font face=3D"Ari=
al">73 <span id=3D"misspell-70" class=3D"mark">de</span> <span id=3D"misspe=
ll-71" class=3D"mark">mal</span>/g3<span id=3D"misspell-72" class=3D"mark">=
kev</span></font></div>=0A  <div>&nbsp;</div>=0A  <blockquote style=3D"padd=
ing-right: 0px; padding-left: 5px; margin-right: 0px; margin-left: 5px; bor=
der-left-color: rgb(0, 0, 0); border-left-width: 2px; border-left-style: so=
lid;" dir=3D"ltr">=0A    <div style=3D"font: 10pt/normal arial; font-size-a=
djust: none; font-stretch: normal;" class=3D"yiv486436119ms__id4288">----- =
Original Message ----- </div>=0A    <div style=3D"background: rgb(228, 228,=
 228); font: 10pt/normal arial; font-size-adjust: none; font-stretch: norma=
l;" class=3D"yiv486436119ms__id4289"><b>From:</b> <a title=3D"m0fmt@yahoo.c=
o.uk" href=3D"mailto:m0fmt@yahoo.co.uk" rel=3D"nofollow" target=3D"_blank" =
ymailto=3D"mailto:m0fmt@yahoo.co.uk">M0FMT</a>=0A    </div>=0A    <div styl=
e=3D"font: 10pt/normal arial; font-size-adjust: none; font-stretch: normal;=
" class=3D"yiv486436119ms__id4290"><b>To:</b> <a title=3D"rsgb_lf_group@bla=
cksheep.org" href=3D"mailto:rsgb_lf_group@blacksheep.org" rel=3D"nofollow" =
target=3D"_blank" ymailto=3D"mailto:rsgb_lf_group@blacksheep.org">rsgb_lf_g=
roup@blacksheep.org</a>=0A    </div>=0A    <div style=3D"font: 10pt/normal =
arial; font-size-adjust: none; font-stretch: normal;" class=3D"yiv486436119=
ms__id4291"><b>Sent:</b> Tuesday, June 12, 2012=0A11:15 AM</div>=0A    <div=
 style=3D"font: 10pt/normal arial; font-size-adjust: none; font-stretch: no=
rmal;" class=3D"yiv486436119ms__id4292"><b>Subject:</b> Re: LF: RE: Class E=
 etc</div>=0A    <div><br>=0A    </div>=0A    <div style=3D"color: rgb(0, 0=
, 0); font-family: verdana, helvetica, sans-serif; font-size: 10pt; backgro=
und-color: rgb(255, 255, 255);" class=3D"yiv486436119ms__id4293">=0A    <di=
v><span>Hi Ken</span></div>=0A    <div><span></span>&nbsp;</div>=0A    <div=
><span>I <span id=3D"yiv486436119misspell-0"><span>believe</span></span>=0A=
you can operate&nbsp;some thermionic devices in higher classes than C&nbsp;=
but=0Athey generally lack the frequency response of a modern <span id=3D"yi=
v486436119misspell-0" class=3D"yiv486436119mark"><span id=3D"misspell-75" c=
lass=3D"mark">FET</span></span>. I=0Awon't go into <span id=3D"yiv486436119=
misspell-2"><span>figures</span></span>=0Abut just think about it. The high=
 <span id=3D"yiv486436119misspell-3"><span>efficiency</span></span>=0Aoutpu=
t stage has to operate like a switch it is not actually an=0Aamplifier. The=
 faster it changes state from fully on with ultra low=0Aresistance to fully=
 off (which&nbsp;means a device that will operate&nbsp;well=0Ainto the&nbsp=
;VHF)&nbsp;the higher the efficiency. If you have a device that is=0Abarely=
 rated to say a couple of megs its not going to be much good (in=0Aterms of=
 what we are talking about)&nbsp;at 500kc/s. Remember you are trying=0Ato g=
et the magnetic field in the inductor to rise and <span id=3D"yiv486436119m=
isspell-4"><span>collapse</span></span> at a very=0Afast <u>rate</u> <span =
id=3D"yiv486436119misspell-5"><span>in-order</span></span>=0Ato generate a =
high electromagnetic field at the drive frequency. We are=0Anot talking sin=
e waves here as a scope on the drain will show. Although=0Aa scope on the o=
utput side of the drain inductor will show quite a=0Aclean looking sine wav=
e. Try it.</span></div>=0A    <div><span></span>&nbsp;</div>=0A    <div><sp=
an>That chart at the end of that <span id=3D"yiv486436119misspell-1" class=
=3D"yiv486436119mark"><span id=3D"misspell-76" class=3D"mark">PDF</span></s=
pan> file=0Ais very clever and is the guide&nbsp;I use to bring a PA into o=
ptimum=0Aperformance.</span></div>=0A    <div><span></span>&nbsp;</div>=0A =
   <div><span>What I was trying to say is that the math is all very=0Awell =
but if you are trying to make a practical and&nbsp;efficient CW TX for=0ALF=
 then&nbsp;there is enough <span id=3D"yiv486436119misspell-8"><span>empiri=
cal</span></span>=0Adata from following the guide lines lines shown on the =
sites I have=0Aposted&nbsp;that will get you a good TX. If you want a docto=
rate in=0Atheoretical physics to <span id=3D"yiv486436119misspell-9"><span>=
bamboozle</span></span>=0Ayou <span id=3D"yiv486436119misspell-10"><span>co=
lleagues</span></span>=0Athen that will detract from the time it takes to b=
uild a very <span id=3D"yiv486436119misspell-11"><span>interesting</span></=
span> high=0Apower, efficient&nbsp;TX design well within anybodies capabili=
ties.&nbsp;The <span id=3D"yiv486436119misspell-3" class=3D"yiv486436119mar=
k"><span id=3D"misspell-78" class=3D"mark">GW</span></span>3<span id=3D"yiv=
486436119misspell-4" class=3D"yiv486436119mark"><span id=3D"misspell-79" cl=
ass=3D"mark">UEP</span></span>=0Adesign being IMHO a very good (Scalable) e=
xample with no&nbsp;<span id=3D"yiv486436119misspell-5" class=3D"yiv4864361=
19mark"><span id=3D"misspell-80" class=3D"mark">RadCom</span></span>&nbsp;s=
tyle=0A    <span id=3D"yiv486436119misspell-6" class=3D"yiv486436119mark"><=
span id=3D"misspell-81" class=3D"mark">unobtainium</span></span>=0Ain the c=
omponents listing.</span></div>=0A    <div>&nbsp;</div>=0A    <div>73 es <s=
pan id=3D"yiv486436119misspell-7" class=3D"yiv486436119mark"><span id=3D"mi=
sspell-82" class=3D"mark">GL</span></span> Pete M0FMT IO91<span id=3D"yiv48=
6436119misspell-9" class=3D"yiv486436119mark"><span id=3D"misspell-84" clas=
s=3D"mark">UX</span></span><br>=0A    <div style=3D"font-family: verdana, h=
elvetica, sans-serif; font-size: 10pt;" class=3D"yiv486436119ms__id4294">=
=0A    <div style=3D"font-family: times new roman, new york, times, serif; =
font-size: 12pt;" class=3D"yiv486436119ms__id4295">=0A    <div dir=3D"ltr">=
<font size=3D"2" face=3D"Arial"> <b><span style=3D"font-weight: bold;">From=
:</span></b> Ken=0A<a class=3D"yiv486436119moz-txt-link-rfc2396E" href=3D"m=
ailto:ken.h.wright@btinternet.com" rel=3D"nofollow" target=3D"_blank" ymail=
to=3D"mailto:ken.h.wright@btinternet.com">&lt;ken.h.wright@btinternet.com&g=
t;</a><br>=0A    <b><span style=3D"font-weight: bold;">To:</span></b>=0A<a =
class=3D"yiv486436119moz-txt-link-abbreviated" href=3D"mailto:rsgb_lf_group=
@blacksheep.org" rel=3D"nofollow" target=3D"_blank" ymailto=3D"mailto:rsgb_=
lf_group@blacksheep.org">rsgb_lf_group@blacksheep.org</a> <br>=0A    <b><sp=
an style=3D"font-weight: bold;">Sent:</span></b> Monday, 11=0AJune 2012, 22=
:09<br>=0A    <b><span style=3D"font-weight: bold;">Subject:</span></b> LF:=
 RE:=0AClass E etc<br>=0A    </font></div>=0A    <br>=0A    <div id=3D"yiv4=
86436119">=0A    <style>#yiv486436119   UNKNOWN {=0AFONT-FAMILY:Tahoma;pano=
se-1:2 11 6 4 3 5 4 4 2 4;}=0A#yiv486436119   UNKNOWN {=0AFONT-FAMILY:Verda=
na;panose-1:2 11 6 4 3 5 4 4 2 4;}=0A#yiv486436119     P.yiv486436119MsoNor=
mal {=0AFONT-SIZE:12pt;MARGIN:0cm 0cm 0pt;FONT-FAMILY:"Times New Roman";}=
=0A#yiv486436119    LI.yiv486436119MsoNormal {=0AFONT-SIZE:12pt;MARGIN:0cm =
0cm 0pt;FONT-FAMILY:"Times New Roman";}=0A#yiv486436119    DIV.yiv486436119=
MsoNormal {=0AFONT-SIZE:12pt;MARGIN:0cm 0cm 0pt;FONT-FAMILY:"Times New Roma=
n";}=0A#yiv486436119    A:link {=0ACOLOR:blue;TEXT-DECORATION:underline;}=
=0A#yiv486436119    SPAN.yiv486436119MsoHyperlink {=0ACOLOR:blue;TEXT-DECOR=
ATION:underline;}=0A#yiv486436119    A:visited {=0ACOLOR:blue;TEXT-DECORATI=
ON:underline;}=0A#yiv486436119    SPAN.yiv486436119MsoHyperlinkFollowed {=
=0ACOLOR:blue;TEXT-DECORATION:underline;}=0A#yiv486436119    SPAN.yiv486436=
119EmailStyle18 {=0ACOLOR:navy;FONT-FAMILY:Arial;}=0A#yiv486436119   UNKNOW=
N {=0AMARGIN:72pt 90pt;}=0A#yiv486436119    DIV.yiv486436119Section1 {=0A=
=0A}=0A</style>=0A    <div>=0A    <div class=3D"yiv486436119Section1">=0A  =
  <div class=3D"yiv486436119MsoNormal"><font color=3D"navy" size=3D"2" face=
=3D"Arial"><span style=3D"color: navy; font-family: Arial; font-size: 10pt;=
" class=3D"yiv486436119ms__id4303">Hi Pete.</span></font></div>=0A    <div =
class=3D"yiv486436119MsoNormal"><font color=3D"navy" size=3D"2" face=3D"Ari=
al"><span style=3D"color: navy; font-family: Arial; font-size: 10pt;" class=
=3D"yiv486436119ms__id4305">About 40 years ago my integration was=0Aquite g=
ood, liked doing 2<sup><span id=3D"yiv486436119misspell-11" class=3D"yiv486=
436119mark"><span id=3D"misspell-86" class=3D"mark">nd</span></span></sup> =
order differential=0Aequations, partial integration and integration by part=
s, the one thing=0AI had big problems with was 3 dimensional integration of=
 a point in=0Afree space . &nbsp;&nbsp;Looking at some of the sites my Clas=
s C <span id=3D"yiv486436119misspell-12" class=3D"yiv486436119mark"><span i=
d=3D"misspell-87" class=3D"mark">MOSFET</span></span>=0APA is probably more=
 like Class E by default. The reason I like valves=0Ais because they are ve=
ry forgiving devices unlike semiconductors, also=0Athe keep the shack and t=
he cat warm.</span></font></div>=0A    <div class=3D"yiv486436119MsoNormal"=
><font color=3D"navy" size=3D"2" face=3D"Arial"><span style=3D"color: navy;=
 font-family: Arial; font-size: 10pt;" class=3D"yiv486436119ms__id4307"></s=
pan></font>&nbsp;</div>=0A    <div class=3D"yiv486436119MsoNormal"><font co=
lor=3D"navy" size=3D"2" face=3D"Arial"><span style=3D"color: navy; font-fam=
ily: Arial; font-size: 10pt;" class=3D"yiv486436119ms__id4309">73s</span></=
font></div>=0A    <div class=3D"yiv486436119MsoNormal"><font color=3D"navy"=
 size=3D"2" face=3D"Arial"><span style=3D"color: navy; font-family: Arial; =
font-size: 10pt;" class=3D"yiv486436119ms__id4311"></span></font>&nbsp;</di=
v>=0A    <div class=3D"yiv486436119MsoNormal"><font color=3D"navy" size=3D"=
2" face=3D"Arial"><span style=3D"color: navy; font-family: Arial; font-size=
: 10pt;" class=3D"yiv486436119ms__id4313">Ken</span></font></div>=0A    <di=
v class=3D"yiv486436119MsoNormal"><font color=3D"navy" size=3D"2" face=3D"A=
rial"><span style=3D"color: navy; font-family: Arial; font-size: 10pt;" cla=
ss=3D"yiv486436119ms__id4315"></span></font>&nbsp;</div>=0A    <div class=
=3D"yiv486436119MsoNormal"><font color=3D"navy" size=3D"2" face=3D"Arial"><=
span style=3D"color: navy; font-family: Arial; font-size: 10pt;" class=3D"y=
iv486436119ms__id4317">M0<span id=3D"yiv486436119misspell-13" class=3D"yiv4=
86436119mark"><span id=3D"misspell-88" class=3D"mark">KHW</span></span></sp=
an></font></div>=0A    <div class=3D"yiv486436119MsoNormal"><font color=3D"=
navy" size=3D"2" face=3D"Arial"><span style=3D"color: navy; font-family: Ar=
ial; font-size: 10pt;" class=3D"yiv486436119ms__id4319"></span></font>&nbsp=
;</div>=0A    <div>=0A    <div style=3D"text-align: center;" class=3D"yiv48=
6436119MsoNormal" align=3D"center"><font size=3D"3" face=3D"Times New Roman=
"><span style=3D"font-size: 12pt;"> </span></font></div>=0A    <div class=
=3D"yiv486436119MsoNormal"><b><font size=3D"2" face=3D"Tahoma"><span style=
=3D"font-family: Tahoma; font-size: 10pt; font-weight: bold;" class=3D"yiv4=
86436119ms__id4325">From:</span></font></b><font size=3D"2" face=3D"Tahoma"=
><span style=3D"font-family: Tahoma; font-size: 10pt;" class=3D"yiv48643611=
9ms__id4327"> owner- <a class=3D"yiv486436119moz-txt-link-abbreviated" href=
=3D"mailto:rsgb_lf_group@blacksheep.org" rel=3D"nofollow" target=3D"_blank"=
 ymailto=3D"mailto:rsgb_lf_group@blacksheep.org">rsgb_lf_group@blacksheep.o=
rg</a> [<span id=3D"yiv486436119misspell-14" class=3D"yiv486436119mark"><sp=
an id=3D"misspell-89" class=3D"mark">mailto</span></span>:=0Aowner- <a clas=
s=3D"yiv486436119moz-txt-link-abbreviated" href=3D"mailto:rsgb_lf_group@bla=
cksheep.org" rel=3D"nofollow" target=3D"_blank" ymailto=3D"mailto:rsgb_lf_g=
roup@blacksheep.org">rsgb_lf_group@blacksheep.org</a> ] <b><span style=3D"f=
ont-weight: bold;">On Behalf Of </span></b>M0FMT<br>=0A    <b><span style=
=3D"font-weight: bold;">Sent:</span></b> 11 June 2012=0A19:16<br>=0A    <b>=
<span style=3D"font-weight: bold;">To:</span></b>=0A<a class=3D"yiv48643611=
9moz-txt-link-abbreviated" href=3D"mailto:rsgb_lf_group@blacksheep.org" rel=
=3D"nofollow" target=3D"_blank" ymailto=3D"mailto:rsgb_lf_group@blacksheep.=
org">rsgb_lf_group@blacksheep.org</a><br>=0A    <b><span style=3D"font-weig=
ht: bold;">Subject:</span></b> LF: Class E=0Aetc</span></font></div>=0A    =
</div>=0A    <div class=3D"yiv486436119MsoNormal"><font size=3D"3" face=3D"=
Times New Roman"><span style=3D"font-size: 12pt;"></span></font>&nbsp;</div=
>=0A    <div>=0A    <div id=3D"yiv486436119">=0A    <div>=0A    <div>=0A   =
 <div id=3D"yiv486436119">=0A    <div id=3D"yiv486436119yui_3_2_0_22_133943=
148539549">=0A    <div id=3D"yiv486436119yui_3_2_0_22_133943148539550">=0A =
   <div id=3D"yiv486436119">=0A    <div id=3D"yiv486436119yui_3_2_0_20_1339=
431485395173">=0A    <div id=3D"yiv486436119yui_3_2_0_20_1339431485395174">=
=0A    <div id=3D"yiv486436119">=0A    <div id=3D"yiv486436119yui_3_2_0_17_=
1339367334490161">=0A    <div id=3D"yiv486436119yui_3_2_0_17_13393673344901=
62">=0A    <div id=3D"yiv486436119yui_3_2_0_17_133936297646643">=0A    <div=
 style=3D"background: white;" class=3D"yiv486436119MsoNormal"><font color=
=3D"black" size=3D"2" face=3D"Verdana"><span style=3D"color: black; font-fa=
mily: Verdana; font-size: 10pt;" class=3D"yiv486436119ms__id4336"></span></=
font>&nbsp;</div>=0A    </div>=0A    <span id=3D"yiv486436119yui_3_2_0_17_1=
33936297646667">=0A    <div id=3D"yiv486436119yui_3_2_0_17_133936297646676"=
>=0A    <div style=3D"background: white;" class=3D"yiv486436119MsoNormal"><=
font color=3D"black" size=3D"2" face=3D"Verdana"><span style=3D"color: blac=
k; font-family: Verdana; font-size: 10pt;" class=3D"yiv486436119ms__id4339"=
>Hi Ken </span></font></div>=0A    </div>=0A    </span>=0A    <div id=3D"yi=
v486436119yui_3_2_0_17_133936297646676"> </div>=0A    <div>=0A    <div styl=
e=3D"background: white;" class=3D"yiv486436119MsoNormal"><font color=3D"bla=
ck" size=3D"2" face=3D"Verdana"><span style=3D"color: black; font-family: V=
erdana; font-size: 10pt;" class=3D"yiv486436119ms__id4344"></span></font>&n=
bsp;</div>=0A    </div>=0A    <div><span id=3D"yiv486436119yui_3_2_0_20_133=
9431485395170">=0A    <div style=3D"background: white;" class=3D"yiv4864361=
19MsoNormal"><font color=3D"black" size=3D"2" face=3D"Verdana"><span style=
=3D"color: black; font-family: Verdana; font-size: 10pt;" class=3D"yiv48643=
6119ms__id4347">Ha ha Stefan, how <span id=3D"yiv486436119misspell-0">good =
is</span>&nbsp;your I<span id=3D"yiv486436119misspell-1"><span id=3D"yiv486=
436119yui_3_2_0_1_13394314853956451"><span id=3D"yiv486436119misspell-17" c=
lass=3D"yiv486436119mark"><span id=3D"misspell-92" class=3D"mark">ntegratio=
n</span></span></span></span>=0AKen?</span></font></div>=0A    </span> </di=
v>=0A    <div id=3D"yiv486436119yui_3_2_0_20_1339431485395169">=0A    <div =
style=3D"background: white;" class=3D"yiv486436119MsoNormal"><font color=3D=
"black" size=3D"2" face=3D"Verdana"><span style=3D"color: black; font-famil=
y: Verdana; font-size: 10pt;" class=3D"yiv486436119ms__id4352"></span></fon=
t>&nbsp;</div>=0A    </div>=0A    <span id=3D"yiv486436119yui_3_2_0_20_1339=
431485395194">=0A    <div id=3D"yiv486436119yui_3_2_0_20_1339431485395202">=
=0A    <div style=3D"background: white;" class=3D"yiv486436119MsoNormal"><f=
ont color=3D"black" size=3D"2" face=3D"Verdana"><span style=3D"color: black=
; font-family: Verdana; font-size: 10pt;" class=3D"yiv486436119ms__id4355">=
Here are a couple of sites that should=0Aanswer your questions. You need a =
good dummy load and a good=0Aoscilloscope. Setting the conditions for the a=
mplifier is to do with&nbsp;=0AA/ the correct driver preferably using a <sp=
an id=3D"yiv486436119misspell-18" class=3D"yiv486436119mark"><span id=3D"mi=
sspell-93" class=3D"mark">FET</span></span>=0Adrive chip (like TC4422 non a=
nd TC4421 inverting) that will turn the <span id=3D"yiv486436119misspell-19=
" class=3D"yiv486436119mark"><span id=3D"misspell-94" class=3D"mark">FET</s=
pan></span>=0Afully&nbsp;on and fully off on each cycle. Very fast rise tim=
e with=0Aaccurate&nbsp;on off timing (mark / space). Ensuring the&nbsp;max =
permitted gate=0Avoltage for the <span id=3D"yiv486436119misspell-20" class=
=3D"yiv486436119mark"><span id=3D"misspell-95" class=3D"mark">FET</span></s=
pan>&nbsp;is not exceeded otherwise they=0Apop, look out for transients, a =
diode clamp helps.&nbsp; B/ Setting the=0Ashunt capacitance and inductance&=
nbsp;in the drain&nbsp;circuit can be done <span id=3D"yiv486436119misspell=
-3"><span id=3D"yiv486436119yui_3_2_0_1_13393673344903182">empirically</spa=
n></span>=0ASee article below. Then follow it with&nbsp;a&nbsp;low pass fil=
ter, although the=0Aoutput wave will be <span id=3D"yiv486436119misspell-4"=
><span id=3D"yiv486436119yui_3_2_0_1_13393673344903251">surprisingly</span>=
</span>=0Aclean.&nbsp;Calculating the values is difficult as you don't nece=
ssarily=0Aknow all the starting&nbsp;parameters and in any case&nbsp;the re=
sult is&nbsp;going to=0Awide of the mark. The site below will gives some st=
arting values. Best=0Ato use 'Scope <span id=3D"yiv486436119misspell-5"><sp=
an id=3D"yiv486436119yui_3_2_0_1_13393673344903332">measurements</span></sp=
an>=0Ato set the output conditions. You are looking for fast, very fast On =
/=0AOff rise times. Gate drive and understanding the drain circuit is the=
=0Akey.</span></font></div>=0A    </div>=0A    </span>=0A    <div id=3D"yiv=
486436119yui_3_2_0_20_1339431485395202"> </div>=0A    <span id=3D"yiv486436=
119yui_3_2_0_17_133936297646686">=0A    <div id=3D"yiv486436119yui_3_2_0_17=
_1339362976466107">=0A    <div style=3D"background: white;" class=3D"yiv486=
436119MsoNormal"><font color=3D"black" size=3D"2" face=3D"Verdana"><span st=
yle=3D"color: black; font-family: Verdana; font-size: 10pt;" class=3D"yiv48=
6436119ms__id4360">These amplifiers are capable of=0Aincredibly good effici=
ency well above a dodgy class C amp. This means=0Athe heat dissipation from=
 the <span id=3D"yiv486436119misspell-21" class=3D"yiv486436119mark"><span =
id=3D"misspell-96" class=3D"mark">FET</span></span> is very low at high pow=
er&nbsp;giving=0Acool h<span id=3D"yiv486436119misspell-7"><span id=3D"yiv4=
86436119yui_3_2_0_1_13393673344903798">eat-sinks</span></span>!</span></fon=
t></div>=0A    </div>=0A    </span>=0A    <div id=3D"yiv486436119yui_3_2_0_=
17_1339362976466107"> </div>=0A    <span id=3D"yiv486436119yui_3_2_0_17_133=
936297646694"></span>=0A    <div id=3D"yiv486436119yui_3_2_0_17_13393629764=
66106">=0A    <div style=3D"background: white;" class=3D"yiv486436119MsoNor=
mal"><font color=3D"black" size=3D"2" face=3D"Verdana"><span style=3D"color=
: black; font-family: Verdana; font-size: 10pt;" class=3D"yiv486436119ms__i=
d4365"></span></font>&nbsp;</div>=0A    </div>=0A    <span id=3D"yiv4864361=
19yui_3_2_0_17_133936297646697">=0A    <div id=3D"yiv486436119yui_3_2_0_17_=
133936297646699">=0A    <div style=3D"background: white;" class=3D"yiv48643=
6119MsoNormal"><font color=3D"black" size=3D"2" face=3D"Verdana"><span styl=
e=3D"color: black; font-family: Verdana; font-size: 10pt;" class=3D"yiv4864=
36119ms__id4368">The <span id=3D"yiv486436119misspell-22" class=3D"yiv48643=
6119mark"><span id=3D"misspell-97" class=3D"mark">GW</span></span>3<span id=
=3D"yiv486436119misspell-23" class=3D"yiv486436119mark"><span id=3D"misspel=
l-98" class=3D"mark">UEP</span></span> (do=0Aa web search) single ended des=
ign is capable good <span id=3D"yiv486436119misspell-10"><span id=3D"yiv486=
436119yui_3_2_0_1_13393673344903405">efficiency</span></span>&nbsp;and=0Ahi=
gh power depending upon the <span id=3D"yiv486436119misspell-24" class=3D"y=
iv486436119mark"><span id=3D"misspell-99" class=3D"mark">FET</span></span> =
used and Drain supply voltage. I=0Ahave modified one to run reliably at 140=
watts and is capable of almost=0Atwice that into a dummy load with a heat s=
ink that is fairly cool.=0AAdjusting L and C <span id=3D"yiv486436119misspe=
ll-12"><span id=3D"yiv486436119yui_3_2_0_1_13393673344903482">empirically</=
span></span>=0Ausing the 'scope to get the correct drain wave shape for max=
 efficiency=0Ais the way to go. The article below shows you what you are lo=
oking for.=0AI set my TX up into a 50 Ohm dummy load adjusting L and C to g=
et the=0Acorrect drain wave shape on the 'scope then measuring the peak vol=
tage=0Aacross the Dummy load.&nbsp;I then transfer my&nbsp;connector from t=
he Dummy load=0Ato the input of the tuned transformer in the antenna <span =
id=3D"yiv486436119misspell-13"><span id=3D"yiv486436119yui_3_2_0_1_13393673=
344903638">up-lead</span></span>.=0AI adjust the coupling link to give the =
same peak voltage&nbsp;across the=0Atuner link turns. You are not looking f=
or maximum peak just the sames=0Aas across the dummy load indicating a 50oh=
m match.&nbsp;This is done by=0Aeither&nbsp;adding or reducing&nbsp;the num=
ber of turns (about two turns) along=0Awith bringing the the transformer to=
 resonance by measuring the peak&nbsp;<span id=3D"yiv486436119misspell-14">=
<span id=3D"yiv486436119yui_3_2_0_1_13393673344903711">up-lead</span></span=
>=0Acurrent, here you are looking for the maximum peak.&nbsp;&nbsp;</span><=
/font></div>=0A    </div>=0A    </span>=0A    <div id=3D"yiv486436119yui_3_=
2_0_17_133936297646699"> </div>=0A    <div>=0A    <div style=3D"background:=
 white;" class=3D"yiv486436119MsoNormal"><font color=3D"black" size=3D"2" f=
ace=3D"Verdana"><span style=3D"color: black; font-family: Verdana; font-siz=
e: 10pt;" class=3D"yiv486436119ms__id4373"></span></font>&nbsp;</div>=0A   =
 </div>=0A    <div>=0A    <div style=3D"background: white;" class=3D"yiv486=
436119MsoNormal"><font color=3D"black" size=3D"2" face=3D"Verdana"><span st=
yle=3D"color: black; font-family: Verdana; font-size: 10pt;" class=3D"yiv48=
6436119ms__id4376">Oh yes and <span id=3D"yiv486436119misspell-25" class=3D=
"yiv486436119mark"><span id=3D"misspell-100" class=3D"mark">WIMA</span></sp=
an>=0Ahigh voltage high value capacitors from <span id=3D"yiv486436119missp=
ell-26" class=3D"yiv486436119mark"><span id=3D"misspell-101" class=3D"mark"=
>Maplin</span></span>=0Awork well.</span></font></div>=0A    </div>=0A    <=
div><span id=3D"yiv486436119yui_3_2_0_17_1339362976466113"></span>=0A    <d=
iv style=3D"background: white;" class=3D"yiv486436119MsoNormal"><font color=
=3D"black" size=3D"2" face=3D"Verdana"><span style=3D"color: black; font-fa=
mily: Verdana; font-size: 10pt;" class=3D"yiv486436119ms__id4379"></span></=
font>&nbsp;</div>=0A    </div>=0A    <span id=3D"yiv486436119yui_3_2_0_17_1=
339362976466116">=0A    <div id=3D"yiv486436119yui_3_2_0_20_133943148539521=
5">=0A    <div style=3D"background: white;" class=3D"yiv486436119MsoNormal"=
><font color=3D"black" size=3D"2" face=3D"Verdana"><span style=3D"color: bl=
ack; font-family: Verdana; font-size: 10pt;" class=3D"yiv486436119ms__id438=
2">Read the articles and search info on=0Aclass E amplifiers.&nbsp;</span><=
/font></div>=0A    </div>=0A    </span>=0A    <div id=3D"yiv486436119yui_3_=
2_0_20_1339431485395215"> </div>=0A    <div>=0A    <div style=3D"background=
: white;" class=3D"yiv486436119MsoNormal"><font color=3D"black" size=3D"2" =
face=3D"Verdana"><span style=3D"color: black; font-family: Verdana; font-si=
ze: 10pt;" class=3D"yiv486436119ms__id4387"></span></font>&nbsp;</div>=0A  =
  </div>=0A    <div>=0A    <div style=3D"background: white;" class=3D"yiv48=
6436119MsoNormal"><font color=3D"black" size=3D"2" face=3D"Verdana"><span s=
tyle=3D"color: black; font-family: Verdana; font-size: 10pt;" class=3D"yiv4=
86436119ms__id4390"></span></font>&nbsp;</div>=0A    </div>=0A    <div>=0A =
   <div style=3D"background: white;" class=3D"yiv486436119MsoNormal"><font =
color=3D"black" size=3D"2" face=3D"Verdana"><span style=3D"color: black; fo=
nt-family: Verdana; font-size: 10pt;" class=3D"yiv486436119ms__id4393">For =
some bed time reading but <span id=3D"yiv486436119misspell-27" class=3D"yiv=
486436119mark"><span id=3D"misspell-102" class=3D"mark">ignor</span></span>=
=0Athe math look at the Tuning Procedure and the pictures at the end which=
=0Atell it all really..... <a href=3D"http://www.cs.berkeley.edu/%7Eculler/=
AIIT/papers/radio/Sokal%20AACD5-poweramps.pdf" rel=3D"nofollow" target=3D"_=
blank">http://www.cs.berkeley.edu/~culler/AIIT/papers/radio/Sokal%20AACD5-p=
oweramps.pdf</a></span></font></div>=0A    </div>=0A    <div>=0A    <div st=
yle=3D"background: white;" class=3D"yiv486436119MsoNormal"><font color=3D"b=
lack" size=3D"2" face=3D"Verdana"><span style=3D"color: black; font-family:=
 Verdana; font-size: 10pt;" class=3D"yiv486436119ms__id4396"></span></font>=
&nbsp;</div>=0A    </div>=0A    <div><span id=3D"yiv486436119yui_3_2_0_17_1=
33936297646670">=0A    <div style=3D"background: white;" class=3D"yiv486436=
119MsoNormal"><font color=3D"black" size=3D"2" face=3D"Verdana"><span style=
=3D"color: black; font-family: Verdana; font-size: 10pt;" class=3D"yiv48643=
6119ms__id4399">For design ideas</span></font></div>=0A    </span> </div>=
=0A    <span id=3D"yiv486436119yui_3_2_0_17_1339362976466122">=0A    <div i=
d=3D"yiv486436119yui_3_2_0_17_1339362976466132">=0A    <div style=3D"backgr=
ound: white;" class=3D"yiv486436119MsoNormal"><font color=3D"black" size=3D=
"2" face=3D"Verdana"><span style=3D"color: black; font-family: Verdana; fon=
t-size: 10pt;" class=3D"yiv486436119ms__id4404"><a href=3D"http://www.class=
eradio.com/" rel=3D"nofollow" target=3D"_blank">http://www.classeradio.com/=
</a></span></font></div>=0A    </div>=0A    </span>=0A    <div id=3D"yiv486=
436119yui_3_2_0_17_1339362976466132"> </div>=0A    <span id=3D"yiv486436119=
yui_3_2_0_17_1339362976466139"></span>=0A    <div id=3D"yiv486436119yui_3_2=
_0_17_1339362976466174">=0A    <div style=3D"background: white;" class=3D"y=
iv486436119MsoNormal"><font color=3D"black" size=3D"2" face=3D"Verdana"><sp=
an style=3D"color: black; font-family: Verdana; font-size: 10pt;" class=3D"=
yiv486436119ms__id4409"></span></font>&nbsp;</div>=0A    </div>=0A    <div>=
<span id=3D"yiv486436119yui_3_2_0_17_1339362976466176">=0A    <div style=3D=
"background: white;" class=3D"yiv486436119MsoNormal"><font color=3D"black" =
size=3D"2" face=3D"Verdana"><span style=3D"color: black; font-family: Verda=
na; font-size: 10pt;" class=3D"yiv486436119ms__id4412">For a good practical=
 circuit for a=0Asingle ended amp&nbsp;that &nbsp;is a <span id=3D"yiv48643=
6119misspell-15"><span id=3D"yiv486436119yui_3_2_0_1_13393673344903559">sca=
lable</span></span>=0Asurefire design, no need to reinvent the wheel.</span=
></font></div>=0A    </span> </div>=0A    <div>=0A    <div style=3D"backgro=
und: white;" class=3D"yiv486436119MsoNormal"><u><font id=3D"yiv486436119yui=
_3_2_0_17_1339362976466159" color=3D"blue" size=3D"2" face=3D"Verdana"><spa=
n style=3D"color: blue; font-family: Verdana; font-size: 10pt;" class=3D"yi=
v486436119ms__id4417"><a id=3D"yiv486436119yui_3_2_0_17_1339362976466149" h=
ref=3D"http://www.gw3uep.ukfsn.org/" rel=3D"nofollow" target=3D"_blank">htt=
p://www.gw3uep.ukfsn.org/</a></span></font></u><font color=3D"black" size=
=3D"2" face=3D"Verdana"><span style=3D"color: black; font-family: Verdana; =
font-size: 10pt;" class=3D"yiv486436119ms__id4419"></span></font></div>=0A =
   </div>=0A    <div><span id=3D"yiv486436119yui_3_2_0_17_1339362976466134"=
></span>=0A    <div style=3D"background: white;" class=3D"yiv486436119MsoNo=
rmal"><font color=3D"black" size=3D"2" face=3D"Verdana"><span style=3D"colo=
r: black; font-family: Verdana; font-size: 10pt;" class=3D"yiv486436119ms__=
id4422"></span><span id=3D"yiv486436119yui_3_2_0_17_1339362976466181"></spa=
n></font>&nbsp;</div>=0A    </div>=0A    <span id=3D"yiv486436119yui_3_2_0_=
17_1339362976466128">=0A    <div id=3D"yiv486436119yui_3_2_0_17_13393629764=
66126">=0A    <div style=3D"background: white;" class=3D"yiv486436119MsoNor=
mal"><font color=3D"black" size=3D"2" face=3D"Verdana"><span style=3D"color=
: black; font-family: Verdana; font-size: 10pt;" class=3D"yiv486436119ms__i=
d4425">For antennas and antenna feed methods=0Aa "look no where else site" =
</span></font></div>=0A    </div>=0A    </span>=0A    <div id=3D"yiv4864361=
19yui_3_2_0_17_1339362976466126"> </div>=0A    <div><span id=3D"yiv48643611=
9yui_3_2_0_17_1339362976466183"></span>=0A    <div style=3D"background: whi=
te;" class=3D"yiv486436119MsoNormal"><font color=3D"black" size=3D"2" face=
=3D"Verdana"><span style=3D"color: black; font-family: Verdana; font-size: =
10pt;" class=3D"yiv486436119ms__id4430"><a id=3D"yiv486436119yui_3_2_0_17_1=
33936297646664" href=3D"http://www.strobbe.eu/on7yd/136ant/" rel=3D"nofollo=
w" target=3D"_blank">http://www.strobbe.eu/on7yd/136ant/</a></span></font><=
/div>=0A    </div>=0A    <div id=3D"yiv486436119yui_3_2_0_17_13393629764664=
5">=0A    <div style=3D"background: white;" class=3D"yiv486436119MsoNormal"=
><font color=3D"black" size=3D"2" face=3D"Verdana"><span style=3D"color: bl=
ack; font-family: Verdana; font-size: 10pt;" class=3D"yiv486436119ms__id443=
3"></span></font>&nbsp;</div>=0A    </div>=0A    <div id=3D"yiv486436119yui=
_3_2_0_17_133936297646655">=0A    <div style=3D"background: white;" class=
=3D"yiv486436119MsoNormal"><font color=3D"black" size=3D"2" face=3D"Verdana=
"><span style=3D"color: black; font-family: Verdana; font-size: 10pt;" clas=
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