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100 watt class E




 
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Author Topic: 100 watt class E  (Read 883 times)
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N4LTA
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« on: October 16, 2018, 02:29:47 PM »

I am looking to build a small 100 watt (carrier ) class E rig for 80 meters  - also may want to go up to 40 meters after I get this one working.

Can anyone point me to a typical circuit?

Thanks in advance
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ka1tdq
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« Reply #1 on: October 16, 2018, 03:02:22 PM »

The truth is out there!

http://www.classeradio.org

I've said this before, but my first class E rig was very simple. I built a 40 meter single FET version and drove it with a Chinese DDS VFO that I bought from eBay. My transmitters are greatly simplified from the website listed above, but they work. The framework for a simple rig is shown under the "Output Circuit Values & MOSFET Ratings" tab.

Also, you can't just turn these rigs on after you build them. I had to experiment a lot to understand how they tune and operate. Once you get the feel for it though, it's like riding a bicycle.

Jon
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M0VRF
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« Reply #2 on: October 17, 2018, 03:09:21 AM »

http://www.w1vd.com/100WclassD.pdf

Is a good place to start....

I have some PCBs for a somewhat different design but same power level, let me know if you're interested.

NCP'A' drivers and TP GaN FETs, with AD9850 DDS.

100W passively cooled, 150W with higher voltage and small fan. I wanted to use a low (48V) voltage which makes the current quite high. With more turns on the O/P tran, a higher voltage could be used and far more power generated.

100W @ 24V was the design requirement.

Regards

JohnB.



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N4LTA
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« Reply #3 on: October 17, 2018, 10:33:55 AM »

I have built several of the W1VD designed for 500 KHz and the other experimental bands down to 62 Khz. Some power levels went to 1500 W carrier.

Was looking for something smaller at higher frequency and likely class E.
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steve_qix
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« Reply #4 on: October 22, 2018, 09:46:02 PM »

100 watts should be pretty easy.  You could build a 2 FET or 4 FET rig (in 2 modules) and use a roller inductor in the output.

I did this using 4 FETS (2 per module), and ran about 35VDC at around 3 to 3.5A.  The FETs are FQA11N90s ($2.80 each).

That rig covered 160 thru 40 meters.

Digital direct drive using 4 IXDD414s (1 per FET).

Unfortunately, I didn't document it in any way.  However, it was the basis for a kit I'm looking at coming out with at some point.

The modulator was an analog modulator (practical at low power like that).

I think I still have some of it intact.  I'll have a look.

The idea was to come up with something that is simple to build, VERY reliable (hence the big FETs) and covers 160 to 40 meters.
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High Power, Broadcast Audio and Low Cost?  Check out the class E web site at: http://www.classeradio.org
N4LTA
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« Reply #5 on: October 23, 2018, 01:43:31 PM »

Steve

That is pretty much what I am looking for. Thanks


Pat
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N4LTA
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« Reply #6 on: November 17, 2018, 01:03:00 PM »

I have four TP90H180PS GAN  Fets and 10 NCP 8107BDR2G drivers that I would like to work with.Any ideas?

Thanks

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ka1tdq
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« Reply #7 on: November 17, 2018, 02:55:32 PM »

Hereís my suggestion. Itís pretty much cookie cutter from Steveís website. Drive the two phases with a DDS VFO from eBay. Use a sine wave 180 degrees out of phase and keep raising the amplitude to get about a 43% duty cycle.

Your FETs have the tab as the source, so you can mount it directly to the heat sink without an insulator.

The transformer winding specs are shown very well on the class E website. Use half the number of cores though for 100 watts.

That should get you started.

Jon


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M0VRF
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« Reply #8 on: November 17, 2018, 07:16:19 PM »

The 'A' drivers are 'easier' to drive.

The PCB I've shown is NCP+GaN.

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