Huh? How can you do RF clipping outside the unit? Not a chance...
Any unit that's inserted in the mic jack is no RF clipper.
www.telstar-electronics.com

As I said. "Obviously they have to contain 'all the works' (oscillator,
balanced modulator, compressor, clipper, filters, balanced demodulator
etc)."

And, as Paul said, "At least Datong made a stand-alone unit. There was an
article about RF-clipping and the Datong unit in Wireless World a few
decades ago."

But maybe Datong didn't know what they were doing.
--
Ian

They had a lot of company, and the residents here have a very short memory.
Datong was second. Comdel made an RF clipper in the late 60's and early
70's. Mike input and amplifier, mixed up to 455 KHz, sideband generated,
clipped the hell out of it, filtered it with a second filter, mixed back
down to audio with the same LO for injection to your mike input jack. Every
serious contester and DXer had one. Cost more than the receiver.

W4ZCB