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Old November 10th 05, 08:35 PM
Michael Black
 
Posts: n/a
Default What is a heterodyne.....


) writes:
Many years ago,Superheterodyne Shortwave Radios were all the
rage,Shortwave Radios wise,that is.There were ads in magazines
gloryfying the advantages of Superheterodyne.Factory made and kits were
available,Superheterodyne Shortwave Radios.
Superheterodyne cuhulin

Maybe the newsgroup would be better if you didn't spew nonsense.
If you know nothing of a topic, don't bother posting.

Virtually every shortwave receiver in production today, and for many a
decade, is superheterodyne. They all convert the incoming signal
down to a fixed frequency for selectivity and amplification.

The exceptions would be fairly obscure kits, using regeneration,
or maybe some commercial amateur radio receivers or transceivers,
using direct conversion (which heterodynes, the incoming signal
directly down to audio).

You'd have to go back many decades before you hit a point where
a large percentage of shortwave receivers were regenerative. Go
back forty, and some would be regenerative, albeit they'd be at
the low cost end of the spectrum. Go back to the thirties, and
regeneration likely was still common, because superheterodyne designs
used more components and hence were too costly for many in the depression
era. Go back to the twenties, and besides cost there were still bugs
(the issue of images for instance), and maybe even a reluctance to move
to something new.

Once again, Howard Armstrong received the patent for the regenerative
receiver in 1914, US patent number 1,113,149,

He received the patent for the superheterodyne receiver in 1920, US
patent number 1,342,885.

And he received the patent for the superregenerative receiver in 1922,
US patent number 1,424,065.

Howard Armstrong took care of all basic receiver design beyond the
simple "crystal radio" and the TRF (Tuned Radio Frequency) receivers.
And took care of that by 1922.

Everything that came later were variants of those three (or more
like two, regen and superhet) basic concepts, incremental improvements
but no fourth type of receiver.

Michael