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E class books




 
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VE3LYX
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« on: September 06, 2017, 12:26:04 PM »

Is there a book on E Class transmitters. IE: E Class AM for Dummies or something? After seeing Nigels VE3ELQ I would like to build an entry level set. My goal is it will.be 12v and biult mostly from.my junk box. I have several power mosfets and I know Nigel will help me over the bumbs but I would like to educate myself a bit in advance.
Don ve3lyx
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Don VE3LYX<br />Eng, DE & petite Francais
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« Reply #1 on: September 06, 2017, 02:49:47 PM »

Don,
A great source of class E transmitter theory with some practical schematics of working rigs is Steve WA1QIX's site here:
http://www.classeradio.com/
Read all of it a few times over until you get a good understanding of it all. Then you and Linda come for a visit, we can talk.  You aint gunna build one any good from junk parts running on 12V. Sad

73s  Nigel
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VE3LYX
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« Reply #2 on: September 06, 2017, 04:32:52 PM »

Why? If the parts are capable what is the difference. This is what I need to understand . Or is it the 12 volts? Usually when learning new tech I like to do a couple junk box builds even if moderate power to get a feel for it. It helps me fo comprehend what I am actually doing so when I go bigger I am comfortable. I have read that page several times now already and did so again. I want to.know more.
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Don VE3LYX<br />Eng, DE & petite Francais
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« Reply #3 on: September 06, 2017, 09:15:34 PM »

As a new class E builder (and not an EE), you can actually build something pretty easily.  The first one I built had a single FET and was driven by a DDS VFO.  Once I understood how to tune it, I built the bigger 8-FET version.

You can do the Cadillac version with all of Steve's circuits, or you can go basic with how I did mine.  I have:

DDS VFO bought from eBay
Analog Heising modulator using a commercially bought audio amp
Mechanical sequencer to make everything happen when it should

But, to do all that and make it work, I visited the class E website about a thousand times.  And even after all that, I still blew up lots of FETs.  I literally keep an extra 30 or so on hand just in case.

Jon
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« Reply #4 on: September 06, 2017, 09:49:12 PM »

I want to thank all the Class E experimenters here who have posted schematics, waveforms, and explanations. My friend Jacob has gotten his MOSFET based Tesla coil projects going much better because of the information about driving the devices at "RF" frequencies in non-switching power supply applications. I've learned a lot as well. I could not advise him on this topic and referred him to these resources.
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VE3LYX
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« Reply #5 on: September 07, 2017, 09:39:08 AM »

I have a digital osc (in fact a couple) that are crystal controlled but trigger a 7400 IC. One used to drive a L317m  voltage regulator and that fed a tank circuit to make it into reasonable rf or sine wave. The transmitter was one of Harry Lyalls creations but work decent. The other I use ALL the time as a crystal test osc . They should be able to supply freq for my project. Heising mod I am familiar with. I have my mosfets , Heat sink hi current RFC , shunt cap , varable cap and gate resistors to prevent runaway. Coil will.be for 160m  and making that is no trouble. An audio amp I can make easily of half the power of the RF amp and I thjnk that should work. Things that confuse me is why is tank series tuned and how to do the impedance transformer for my 79 ohm antenna. And where to put it ie aheaf of tank or after tank.
Don ve3lyx
 
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Don VE3LYX<br />Eng, DE & petite Francais
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« Reply #6 on: September 07, 2017, 10:32:01 AM »

I'm not the authority here, but I'll tell you how I did my first FET rig. 

You should not have a problem loading into something other than 50 ohms.  79 ohms should be just fine.  The loading capacitor I'm guessing will be able to match it.

Use a 5 volts-ish sine wave to drive the IXDD device before the FET, using a scope obviously.  Using a cheap Chinese DDS VFO is nice because you can adjust the amplitude of the sine wave to get the duty cycle you want.  Just so I didn't blow things up, I used 12 volts on the drain to experiment.  After all the waveforms looked good I increased to the operational 48 volts.

Follow the tuning procedure on the class E site.  It'll get you there.

I've found that this class E stuff is pretty forgiving and the component values aren't really critical.  Ballpark stuff usually works.

Jon

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« Reply #7 on: September 07, 2017, 11:51:13 AM »

Tnx
Don ve3lyx
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Don VE3LYX<br />Eng, DE & petite Francais
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« Reply #8 on: September 08, 2017, 04:54:47 AM »

Just this circuit, simple inexpensive parts, can supply a PCB if you want.....

The IRF510 wont work well in this circuit however so best to use an IRL520.

Better still use the TPS GaN devices from Transphorm, you wont have any in your junkbox however!

They'll give a 40W carrier easily (@24V wi GaN ONLY) and use T106-2 toroids, @12V expect 10W carrier (from either device).

J.


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VE3LYX
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« Reply #9 on: September 08, 2017, 06:28:56 PM »

Ok I am looking that over. I need to come up with a driver between my square wave osc and the mosfets. I made a impedance transformer today. I found my squarewave chip.oscillator and it is all intact and good. Need to choose a crystal and wind the tank coil to match that freq. I found a 386 based audio amp I built a few years back. That can be the basis for my modulator but it will.need a boost to make it usable. To drive my mosfet for heising modulation. I think onr should do to.modulate two (1/2). I dont have a elrcronics scope but I do have a KAL automotive scope develped for elevtronic fuel sydtem diagnosis and it will read miniscule  voltages to several KV and may be more suitinle then one might think. I demoed these for several years as well as used them daily in.my shop do am very familiar with them . I will tesy it on.the square wave osc and see what kind of pattern it produces.
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Don VE3LYX<br />Eng, DE & petite Francais
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« Reply #10 on: September 09, 2017, 12:28:50 PM »

Hi Don.

Yes the circuit is very simple and just stuff your square wave into pin 2 of the 74HC240 (thats acting as the driver BTW)

Not sure why you want to use 'Heising' modulation but even simpler just use class A and use your 386 to drive a current amp like a 2N3055 in series with the supply.

OK (ish) for a 10W carrier, anything higher and it gets too hot.

I'd look at PWM vastly superior in evey way.....

Do get a 'scope, second hand ones are cheap, no excuse not being able to see those electrons!

J.
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VE3LYX
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« Reply #11 on: September 10, 2017, 07:02:42 AM »

Ok. I have 2n3055 s . Pwm is the goal for my fancy rig but this is my learning rig. My scope is already equiped to.monitor PWM because that is how Electronic Fuel Injection controls variable demand inside the fuel curve on top of RPM cycling. I suspect it will prove to be a good scope to use. Nice 12 inch screen . Solid sate circuitry
 Inductive snd capacitive pickup. No direct connection required. And I know how to use it to test almost anything.
Don ve3lyx
So I tried it to see the osc wave form. While it is discernable. Not quite square but close (corners rounded) sweep is not fast enough to get a small enough cycles in the pattern to be of practical use. However it is something I have wondered about trying for a long time so well worth the fun of knowing. Scope stilll works though and voltage wise the is signal is decent and should be able to switch what I wish. I tried it with a 3560 crystal.
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Don VE3LYX<br />Eng, DE & petite Francais
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« Reply #12 on: September 11, 2017, 02:20:42 PM »

Here is the initial.lash up well underway. Squarewave osc on.left (long chip) and 386 amp.on.right (short chip) . Since these worked in.their previous project that saves reinventing the wheel. I stole the crystal from this osc but it is a simple matter to reinstall it. Front long aluminum.strip.holds the two PA mosfet and single aluminim bracket holds the single audio section amp which will.feed hi.level.audio to the incoming power supply line at the heising choke. I still dont understand why series tank tuning is often used but I have all.the tank parts in stock already made. They just need a place to stand. And the whole thing may be a bust although it should work to some extent.  Hopefully it wont take much to get it functioning decent. Ecpense so far , zip. Totally from.my junk box/parts bin. If I like  it (E class)I will do a nice one like Nigels.
Don ve3lyx


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Don VE3LYX<br />Eng, DE & petite Francais
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« Reply #13 on: September 13, 2017, 08:11:26 AM »

That said someone should do an E class book. Not too heavy and not too thick. Someone who is quite practical. There is a need. 
Don
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Don VE3LYX<br />Eng, DE & petite Francais
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« Reply #14 on: September 21, 2017, 05:44:57 PM »

Many years ago in the last century I built a 5 watt CW transmitter from a circuit Harry Lyall (SM0....)discovered accidently thru a circuit board error. I used a LM317 regulator chip and LC tank tapped unusually to give a good dignal on 160m.  I built it back then and with all this E Class talk wondered if that was an E Class circuit functioning mainly as a switching device feeding a tank which finished the job of producing the sine wave. Maybe I am off base but that is what I am thinking. Anyway I found it yesterday.  I knew I still.had it somewhere. It has been cannibalized but the main components are still there. When I built it I drove it with that 7400 chip.osc I referred to elsewhere. Now they just build it as a power osc. Just wondering out loud if Harry was ahead of the curve.
Don ve3lyx
This afternoon I put that regulator chip transmitter bavk together. Couldnt find my lm317 but had a 7812. You have tobhave the chip on rehulator it swutching function so I fed it from a couple of 9 volts and tunef it for 40m.  Silly thing still works! Now to modulate it.
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« Reply #15 on: September 24, 2017, 05:14:46 PM »

Don,

A book on Class E that I have here and cherish is an engineering textbook.  
It is titled ‘Solid State Radio Engineering’ by Herbert L. Krauss, Charles W. Bostian, and Frederick H. Rabb.
Copyright 1980, published by John Wiley & Sons, Inc.  
Hardback, 534 pages, silver cover, about 1 1/8” thick.  
ISBN 0-471-03018-X.

I was lucky enough to spot it at a hamfest.  Chapter 14 covers Class D, E, F, and S power amplifiers. One page I like is Appendix 14-1 p.472 Tabulation of PA Characteristics.  I think I scanned this in once and posted it on a Class E forum thread a number of years ago.

(petite Francais aussi)
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VE3LYX
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« Reply #16 on: September 25, 2017, 09:19:57 AM »

Just this circuit, simple inexpensive parts, can supply a PCB if you want.....

The IRF510 wont work well in this circuit however so best to use an IRL520.

Better still use the TPS GaN devices from Transphorm, you wont have any in your junkbox however!
This I can do. The chip.osc I am very familisr with. The vxo addition should work well. Heising I have done as well am very familiar with  series cathode mofulation.  Also very familiar with loop.modulation from the pre 1920s and have tried it on my tuna tin tx just for fun. Pwm I know from my many years as an auto tech as ut is used in electronic fuel injection. What I dont know about pwm is what to use.
Or order
Don

J.
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Don VE3LYX<br />Eng, DE & petite Francais
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« Reply #17 on: October 01, 2017, 03:46:59 PM »

So I did a junkbox build of your simple circuit using IRF  1404 I had laying around . I drove it with the 7400 chip osc and keyed the IRF1404 leaving the osv running. Despite being a junk box build it works although not as good as yours. I am only getting about 4 watts carrier. Tomorrow I will hook up the 386 and give it some modulation. I had to guess at some of the values . Good practice run.
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