On Wed, 2006-07-12 at 21:06 -0500, James Duffer wrote:
> Is this -160 dbm? What is the level of ambient noise?
> Would it be less than 1 micromicromicromicro watts.
> The point is what good is having a sensitivity that would allow
> detection of signals that are below the noise floor????
> Jim de wd4air
The noise floor is not a stable signal level, nor uniform over the
world. There are quiet locations and quiet times, some predictable, and
some not. Then there may be some signal processing techniques to copy
signals that to the ear are weaker than the noise. A few of us can do
that by ear, so it can be handy to have reduced the noise contribution
of thee receiver so its not the limit, so that external noise is always
the limit and there's still room for ear or computer processing to copy
signals 20 or more dB below the noise level. To those ears, a signal at
MDS is nearly S-9.
73, Jerry, K0CQ,
All content copyright Dr. Gerald N. Johnson, electrical engineer
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