From Todd/VE7BPO/@QRPHB of QRP HomeBuilder is the K3NHI sweep system that he built. He put out a call asking for people to host a zip file of his build and I offered to stash them here for him.
Inside the zip file you’ll find a description of the sweep generator, schematics, build notes and lots of pictures by Todd.
Zip file: K3NHI sweep system or here
It’s a pretty cool looking build. I’ll have to spend some time studying it when I get a chance.