Wayne's Class-H modulator

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Wayne's Class-H modulator

Postby Brent » Wed Mar 28, 2007 7:04 pm

I had the pleasure of visiting Steve QIX in Townsend, Ma and WA1SSY Wayne had brought his modulator over for debugging. I was impressed by the beautiful job Wayne did on the modulator and can't wait to see the RF deck when its completed. Steve did have a post on the AMForum, but it must have been pulled or redirected?

Also a big thanks to Steve for his help. The modulator driver had the ground for the charge-pump going to the floating board instead of the chassis and was the route of the problems for the past 2 years. It was amazing that the rig ran at all?!

I decided to put Steve's PDM generator board in the rig and remove the old deag-bug PDM board that I built 2 years ago. I had dragged the whole modulator chassis over to Steve's to debug and found a 22pf cap instead of a 220pf on the new board....he was surprised to see the clock frequency running at 1.5 megahertz. HA!

So after repairing the RF deck and tweaking the modulator, the big rig is back and better than new.

Stayed tuned for the newr design by QIX labs.

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Postby frank carcia » Wed Mar 28, 2007 8:19 pm

Man that heat sink Wayne used looks like it would support a 1 KW rig.
What a nice job!
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SSJ Pics

Postby nu2b » Thu Mar 29, 2007 12:24 pm

Waynes pictures are in "QSO" Mar 27


This is really a nice job.
Looks like it might be built on a TechMar chassis.

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Postby steve_qix » Fri Mar 30, 2007 7:53 pm

Here's the actual post I put up on AMfone :-)

Wayne, WA1SSJ brought his new modulator - power supply down to my place to check out and fire up for the first time !

I was really impressed by the incredible construction job and attention to detail. Almost "military like" in the number of screws, labeled wires, tiered levels, etc. And, it worked and sounded every bit as good as it looked.

This power supply / modulator is designed to work with transmitters up to 500 watts carrier, and will modulate the carrier up to 200% positive ! The underlying topology is class H (analog).

Notice the stamped front panel with inlaid lettering. Nice job !

Here's the front panel:

Here's the inside:

Here is a closeup of one of the PC boards:

Here's a closeup of one of the meters:
Visit the class E web site at:

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