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40 meters - 100 watts




 
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Author Topic: 40 meters - 100 watts  (Read 661 times)
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ka1tdq
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« on: July 04, 2018, 10:30:20 PM »

I'm starting another class E transmitter.  Here's the picture of progress so far. 

It'll be two FETs in parallel for 100 watts carrier on 40 meters.  I decided to go with an ATC capacitor for the shunt this time.  It makes things more compact.

Jon


* IMG_1063.jpg (3179.32 KB, 4032x3024 - viewed 114 times.)
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ka1tdq
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« Reply #1 on: July 06, 2018, 11:03:22 PM »

I need to remove the assembly to mount the mica insulators (I can never find those when I need 'em), but this is how the heatsink will look.

Jon


* IMG_1069.jpg (2556.09 KB, 4032x3024 - viewed 88 times.)
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ka1tdq
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« Reply #2 on: July 07, 2018, 06:55:30 AM »

The heat sink assembly is now all done.  The rest of the work is just brute force chassis assembly. 

Jon


* IMG_1070.jpg (3485.46 KB, 4032x3024 - viewed 89 times.)
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steve_qix
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« Reply #3 on: July 13, 2018, 02:21:16 PM »

You may be better using one driver per MOSFET and not putting the gates in parallel.  I have had much success with such a design.

Watch out for parasitics.  Resistors in series with the driver inputs will help.

Keep us informed as to your progress!
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High Power, Broadcast Audio and Low Cost?  Check out the class E web site at: http://www.classeradio.org
ka1tdq
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« Reply #4 on: July 17, 2018, 01:21:45 AM »

I'm waiting on a coworker to finish painting the enclosure. He's much better at painting than I am, with my skills being just a step above graffiti.  He also did the black rack/cabinet in my shack and did an awesome job.  

Each FET does have its own driver. The only resistors I'm using are pull-downs for the driver bus and the wave shaper. The entire FET assembly is pretty tight, in fact the most compact I've ever built, so I'm keeping my fingers crossed that it'll cut the mustard for 40 meters.


Jon
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