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Old September 28th 06, 04:56 PM posted to rec.radio.shortwave
Michael Black Michael Black is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 322
Default Low-RF Computer?

"Seeing-I-dawg" ) writes:
"Heterodyne" wrote
Avoid the wireless KB and mouse..
My last set splattered "digital" pulse noise all over the place. Ugh! I
could clearly hear the mouse splatter in the 10/11M bands everytime I
moved the mouse.


That's because yours operates in the 27mhz band.


Then my IR remotes must all be operating on 1mhz using spread spectrum
frequency hopping technology.


If you're talking actual IR, then of course they are infrared. And if you
mean remote controls, then I think it's safe to say that they all use IR at
this point. (There was a time when tv remotes used ultrasonic sound,
and recently I read of an old tv remote that did use radio.)

It's worth pointing out that most bits of equipment using IR for
a wire free connection tend to modulate the IR emitter with a "carrier"
that's above audio frequencies, such as in the 40KHz range. Those tend
to include harmonics, so if you hold an IR remote next to an antenna,
you are likely to hear something; of course it depends on the unit and
how many times the actual frequency you are listening to.

But, at least some of those wireless keyboards and mice use 27MHz.
They say so right in the flyer. Presumably they use radio rather than IR
so there's no issue with line of sight, and 27MHz has been allocated for
low power use for decades (and may be a lot safer for the use now with
a lot of the traffic presumably out of there). It's still low enough
in frequency to be cheap to work with.

I imagine other wireless keyboards and mice might use higher frequencies,
using some other allocation for low power license free use.

Michael