Hmmm, all very interesting...

K7ITM wrote:

Additional cons:
- Increased noise from the regeneration

As in all regens, it comes with the territory!


- Potential for distortion introducted by the regeneration

Which may be also a plus, if detection is to be accomplished in the
same stage. In normal concentrated-LC circuits up to HF or low VHF
rejection of signals at f/2, f/3 (which could be picked up and
amplified as a harmonics at f) tends to be good enough. This always
looked a bit counterintuitive to me, but it works. In cavities I think
one can also expect spurious resonances - no idea if regeneration makes
the whole contraption lock on the main resonance (that of the resonator
at fundamental) and kill all spurs.


- Non-flattopped response because of the single resonator

I wouldn't be too surprised if it turned out to be too tight for voice
(I can't do the math w/o a lot of additional learning though, any help
is welcome) but it would still be OK for CW. Regens are used for SSB
as well, and LCs have been used for ultimate selectivity until recently
(see Drake R8), but clearly curvy is a distant second best to flat.


- To get high Q with reasonable regeneration still requires a
BIG resonator (at VHF).

YESSS! The resonators I've seen were rather thick brass stubs, and
even w/o regeneration could kill off a transmitter signal off frequency
by 10%. As a first step I'd play with a ground-insulated loop made
with either a ~ 0.5-1 in. wide strip or pipe. I/O with coax-fed links
worked off ground, and a 50 ohm broadband amp as regen. I feel mired in
my deep ignorance - as in antennas, what should be avoided to avoid
broad resonances?


High regeneration is difficult to make stable.

This would definitely be a hands-on radio, like any regen.


A long time ago, I worked on a receiver that applied gated regeneration to the energy introduced into a cavity
by an antenna,
But that design was optimized to accomplish a special task,

By any wild chance was it an ECM? I remember that such a solution was
used in radar jamming. Cavity was powered, kept right below
oscillation. Pulse comes in, big punch goes out on the same frequency.
(You don't have to answer this one! ;-) ).

Or was it a self-activating oven klystron for genetically engineered
microwave-emitting poultry?