Re: RX sensitivity #v6

Joe Puma

Its always refreshing to see Allison popup out of the blue  =)


Hi Allison!





Sent from Mail for Windows 10


From: ajparent1/kb1gmx
Sent: Wednesday, March 4, 2020 2:49 PM
Subject: Re: [BITX20] RX sensitivity #v6


On Sun, Mar 1, 2020 at 03:30 PM, Rick Tilton wrote:

He put it on his equipment to check SNR and it came out to 1 microvolt? 

Likely with a 10db S+N/Noise  and for HF 1uv is not that bad. 
That a signal and noise that is greater by 10DB than just the
noise output alone.   That means at about 10db less signal you
may still hear it (maybe weakly) which is still good.

FYI: a lot of well known radios .5uv for 10dbS+n/n is a very common
number.  Why not better?  At HF galactic and man made noise is 
sufficiently high enough that that will (very) easily be heard on a
receiver of that sensitivity.

The figure given in the published spec is really MDS of .2uV. as in
minimum discernible signal (enough to raise the average signal plus
noise level by 3DB).  That's actually pretty good.  For the test set
that may work out to a noticeably higher number (typically does).

>>> I did not get anywhere close to .01 microvolt?
RX sensitivity of .01uV, seriously?  getting .1 is very good,
but .01uV would be very hard to achieve.

Experience and reading specs for many radios would give
and idea of what normal and expected is.  Being inexperienced 
by your own words you do not have an idea of normal or expected.
Also measurements and measurement methods are well standardized
so those that understand them know what it means and how it was
arrived at.

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