🚀 go-pugleaf

In article <17660105@hpfcdj.HP.COM>, myers@hpfcdj.HP.COM (Bob Myers) writes:
> >Sorry, but this is wrong. The 'super' in superheterodyne is actually
> >a contraction of 'supersonic' referring to the fact that the
> >heterodyne produced is above the range of audible frequencies (i.e.
> >an RF heterodyne).

> An interesting theory, but I suspect that it's incorrect as far as the
> actual origin of the word is concerned.  When Armstrong invented the
> superheterodyne technique, the most "refined" receiver type available
> was called the "super-regenerative" (which, I assure you, had nothing to
> do with regenerating supersonic frequencies - although the "regeneration" 
> *did* take place in the RF stages).  I suspect that he simply picked up the 
> "super" prefix from this as a Good Marketing Move.

From the murky depths, I dredge these definitions, and a bit of radio
technology history:

(I am semi-ignoring the original spark-gap receiving loop, and other
experimental receivers.  Was the coherer actually used outside of
the laboratory?)

Crystal Set: Probably the first common receiver -- used a non-linear detector
and a tank circuit (parallel-resonant) for selectivity.  No RF amplification,
and (I think) no audio amp.

TRF: Tuned Radio Frequency -- Placed one or more amplifying stages before
the detector.  These were all tuned to the receiving frequency, and often
had individual tuning controls for each stage.  Because of unavoidable
feedback, the maximum gain was limited: too much and the thing became a
tunable oscillator.  This inexorably led to the...

Regen:  Regenerative receiver -- The gain was adjusted to the threshold
of oscillation.  All sorts of things happened then; there was a "Q-multiplier"
effect for improved selectivity, and the sensitivity was greatly improved.
As you might imagine, the concepts of dynamic range and intermodulation
were not widely applied, except in the negative sense (What I am trying to
say is that the regen was a *weak* receiver -- susceptable to overload
from interfering stations.)  Fortunately, there wern't a whole lot of
signals on the air back then.

Super-regen:  This took a regenerative design, and allowed it to oscillate,
but "quenched" the oscillation at a supersonic rate.  This technique provided 
nearly all the sensitivity of the regen design, but with much improved 
ease-of-use (no adjustment of the gain / feedback required).  The super-regen 
saw use at frequencies up to at least 50 MHz.  The drawbacks were a hissing 
background noise -- caused by the supersonic quench rate -- that gave rise
to the slang term "rushbox" for the super-regen, and the fact that the 
oscillating front end created a broad, noisy signal that radiated back through
the antenna port, often causing interference to neighboring receivers.

Superhet:  This has been well described in the past few days on the net.  
I suspect that the "Super" prefix *was* marketing-speak, but it also could
have referred to the supersonic frequencies involved in the heterodyning
process (I'm guessing here).

By the way, I'm not really an Olde Phart; I've never used anything older
than a superhet.

-Paul, wb6cxc

-- 
      Paul M. Elliott      Optilink Corporation     (707) 795-9444
               {uunet, pyramid, tekbspa}!optilink!elliott
"an archetypal entity..., superimposed on our culture by a cosmic template."