On Apr 14, 11:46�am, spamhog wrote:
As the sunspot cycle is inching forward, I've been considering adding
an upconverter to Charles Kitchin's 50MHz audio-squelched superregen
design, in order to make a sensitive and very quickly tuneable
15-30MHz receiver intended to take the pulse of propagation on the
higher HF bands. �The idea came from an unpretentious Russian design.
(No, it wasn't a fremodyne).

In a classic case of mission creep, I observed that a fixed IF lends
itself to a further step. I searched for prior art in inducing super-
regeneration in a resonant cavity.

If that could help narrowing the passband, it would be a nice trick
for upconversion.

I found few and laconic references at almost-otherwordly microwave
frequencies, Gunn diodes, folded spectra, etc etc.

If I could make a resonant cavity in no time I'd not ask for advice
before jumping in, but this would be my very first, and shooting for
40-60Mz IF it risks being somewhat monumental - short of pigtailing
the resonator, or doing a folded design, or some other "Grande
Complication" which might negate the very idea of using a cavity.

****** � Prior art pointers, anyone? � �******

TIA

Filippo N1JPR


IIRC N1TEV's design used a sine wave waveform in the quench
oscillator. As such the receiver is slope controlled, in which case
the bandwidth depends upon the rate of change of the admittance across
the tuned circuit as it goes into an oscillation condition, and not
the Q of the resonant circuit.

The standard reference is "Super-Regenerative Receivers", by J.R.
Whitehead, Cambridge University Press, 1950.

73 John KC0G