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Hi
Graham, LF,
Well
here looking at WSPR with Spectrum Lab running the other week I came to the
conclusion that:
1.
Adjusting the input level to the PC such that WSPR indicates a Noise level of
0dB corresponds to -60dBfs in Spectrum Lab.
2. A
signal reported as -30dB in WSPR will measure -60dBfs in Spectrum Lab, and be
indistingushable from the noise. 3. A signal reported as 0dB in WSPR will measure
-30dBfs in Spectrum Lab
4. A
signal reported as +10dB will measure -20dBfs in Spectrum
Lab.
5.
Raising the Noise level reported by WSPR to +10dB will correspond to -50dBfs in
Spectrum Lab. But this only reduces the dynamic range of
WSPR.
To me
it appears WSPR prefers the Noise floor to be around -60dBfs giving it a 30dB
margin over the A/D theoretical noise floor.
These
tests were done during the day, when there was little QRN and
QSB.
AGC
off, and sufficient RF attenuation to achieve 0dB Noise level reported by
WSPR.
73,
Lee
M0LMH.
Just watched Dave's G3YXM wspr signal
on spec-lab ,
Spec-lab showed the signal to be a
constant 20 dB over the back ground noise floor of the rx
so in my book that's 20 dB
s/n
The wspr decode is showing -3
dB s/n ?
What is it actually displaying
?
G ..
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