John Larkin wrote:

On Mon, 20 Apr 2009 13:57:26 -0700 (PDT), Tim Shoppa
wrote:

On Apr 20, 3:44 pm, John Larkin
wrote:
On Mon, 20 Apr 2009 12:23:53 -0700 (PDT), Tim Shoppa

wrote:
On Apr 20, 1:10 pm, John Larkin
wrote:

http://en.wikipedia.org/wiki/Superheterodyne_receiver

I saw that in Wikipedia too. I didn't believe it, it doesn't make
sense. Why not just call all radio frequencies and IF frequencies
above 20kHz "supersonic"? Then all radios (*) are supersonic, and
we're back to super meaning nothing at all.

Possibly because heterodyne receivers mixed to sonic frequencies.

I didn't really trust Wikipedia on this (it uses unusual language to
talk about perfectly conventional subjects) but I did find my December
1922 QST, and it says (page 11):

In December, 1919, Major E. H. Armstrong gave
publicity to an indirect method of obtaining
short-wave amplification, called the Super-
Heterodyne. The idea is to reduce the incoming
frequency which may be, say 1,500,000 cycles
(200 meters), to some suitable super-audible
frequency which can be amplified efficiently, then
passing this current through a radio frequency
amplifier and finally rectifying and carrying on
to one or two stages of audio frequency
amplification.

To me that sounds a little less awkward and more natural than the
derivation that Wikipedia tries to draw.

Tim N3QE

I did like the wiki bit about people using hundred-tube TRF receivers.


And the claim that a TRF receiver was simpler to use than a
super–heterodyne. It makes you wonder if the author even knows how a
TRF receiver works. Most had a separate knob per tuned circuit, since
the attempts at gear driven tuners didn't track very well.




--
You can't have a sense of humor, if you have no sense!