Class E Transmitter

[WA4JK]

To all of the Class E builders, do any of you have a complete parts list for a 160,80,40M transmitter. I'm going to jump in and try to build a complete PWM, Transmitter with three separate RF decks at 1KW. But I have no clue where or if a bill of materials might be posted. I looked on the Class E web site, but unless I try to pull from the drawings, I could not locate a bill of materials. Thanks

[n1ps]

We're not these yet.   Nobody to my knowledge has built a complete TX that operates satisfactory on all 3 bands.  So therefore no BOM.  I dont believe a single RF deck can function on all 3 bands without a lot of control relays and different drivers.  I believe 40 is the biggest challenge but not an expert in this band at all with respect to class E/D.  Steve QIX is currently experimenting on 40 using some of the new SiC fets and has posted some of his results on this forum.  An 80/160 TX has been made and does work well.  Several people have made dual band transmitters with good results.  My suggestion is to start with 80/160.  We are all waiting on Steve's final thoughts and designs on the SiC fets.  They could change the game.

IMHO the real challenges for building a class E/D TX are the mechanical aspects. Especially for the RF deck.   In my case I first found a heatsink then made a chassis around it. 

So my advice...from the village idiot....is to make a plan and build one.  Plenty of help is available here.  No BOM required.

~ps

[steve_qix]

Well, to start you could build a single RF deck for 80/160, and a 2nd deck for 40.  This will save you some money over 3 separate decks.

But, to answer the question directly, there isn't a true cookie cutter home built solution, but it is VERY close.

Break the project into parts.  The modulator / power supply is very well defined.  There are complete schematics.  Experienced class E builders can help with specific component values for things like the modulator PWM filter.  And, you can get questions answered.

So, figure the modulator/power supply parts first.  Break that down into blocks.  The power supply and its controls (relays, etc.); the PWM output stage and filter; the PWM generator and audio input; and finally the overload/shutdown and all the overall control circuitry.

Then figure the parts for two RF amplifier decks.  Maybe just start off with 80/160 and get that going.

For me personally, the physical enclosures/chassis/cabinets (rack mounted in my case) are probably the most difficult hurtles.  You have to think about metering.  None of it a big deal, but all needs to be considered.

I do not know how much experience you have building.  That will make a BIG difference.  If you've built a lot of stuff, common sense and experience will be your friend.

If not so much experience, that's OK too - a fair number of "newbie" builders have successfully put these rigs on the air, and this was their first project!

Your infrastructure may or may not need attention as well - don't know what you've got in place for T/R systems and things like that.

You also need to know what your frequency source is going to be.  Are you planning on building a VFO, or are you going to use some pre-existing frequency source (such as a rice box running at a watt or so)?

[WA4JK]

Sorry Folks you can tell I'm new in this arena. I've never built anything solid state. So I'm draining the collector of my brain just trying to understand the terminology.
So if you don't mind my asking, what is the average (if it exist) cost to build one of these?

[steve_qix]

The cost depends on what you have around for parts, and what you have to buy.

1kw - let's say an "Am killowatt" - 1kW input.

Do you have an air or vacuum variable cap - 1000pF at around 6kV or greater?  If not, you need one.

Loading cap - something greater than 1500pF

Power transformer: An SU-2 or DU-2 is ideal.  You need around 105VAC on the secondary - a 1.5kva transformer.  What do you have around the shack?

Cabinetry/chassis?  What do you have in your stock of these types of things.

If you have a well equipped junk box (or some old transmitters you are going to convert from tubes to solid state) you can save BUNDLES of money.

VFO and/or frequency source?  What (if anything) do you have?

Regards,  Steve

[WA4JK]

Nothing... not a darn part one anymore. All sold before I moved. Boy do I feel naked...