Hello All: I believe the Clipper is a in line attenuator that not only attenuates the noise but also the received signal. Not good.
As with most all EMI/RFI ( Electromagnetic Interference / Radio Frequency Interference ) you want to stop the noise at the source, but not all ways doable or practical. The NB Nose Blankers I've seen usually all work quit well, removing pulse type noises. Allowing the radio receiver to hear most all signals in a mobile installation.
I wonder if the Mocat used Motorola's Extender design.
The Extender had two front end filters tuned to different parts of the band. The extra filter sampled noise pulses an "unoccupied" part of the band and blanked the noise impulse after the IF filter delay.
That patent must be long expired by now. Hmm, maybe time for an aftermarket kit for CB radios.