 | Virus-free.www.avg.com |
Don't put too much in those S/N reports.
It looks like, assuming that is stable ground wave or direct wave
propagation and the noise levels are stable, the F-120 is about
half the effective bandwidth or a bit less than half of the W2
signal bandwidth.
First, the reported S/N it is a snapshot of time. Neither the
noise or signals are constant levels over time. At any instant of
time S/N can change significantly.
Second, it is the wide bandwidth noise compared to the narrow
detection-bandwidth signal level. It isn't the actual
signal-to-noise. The way it is calculated in digital modes
typically inflates the apparent S/N by at least 15dB over what it
really is.
For example, I can copy the CW ID of stations on WSPR that are
reporting -15dB or worse on WSPR from across the room if I have
the monitor speaker on. This is because my ears are trained to pay
attention to the single frequency tone of maybe 100Hz or less BW
and the noise BW is 3kHz. That's log 10 (3000/100) = 15dB right
there.
Don't put too much meaning in those S/N reports. They really don't
mean all that much if we ignore the variables.
73 Tom
Using the same power, FW2 gives different report than wspr2
4 spots:
Timestamp Call MHz SNR Drift Grid Pwr Reporter RGrid km az Mode 2023-04-09 02:36 W0YSE 0.475729 -12 0 DN41ah 0.005 KA7OEI-1 DN31uo 43 320 W-2 2023-04-09 02:32 W0YSE 0.475693 -16 0 DN41ah 0.005 KA7OEI-1 DN31uo 43 320 F-120 2023-04-09 02:16 W0YSE 0.475744 -12 4 DN41ah 0.005 KA7OEI-1 DN31uo 43 320 W-2 2023-04-09 02:12 W0YSE 0.475646 -15 0 DN41ah 0.005 KA7OEI-1 DN31uo 43 320 F-120
running wspr2 for rest of the night.
73 and GN all*´¨)
¸.•´¸.•*´¨) ¸.•*¨)
(¸.•´ (¸.•` Neil , wØyse, DN41ah, North Ogden, Utah 84414
______________________________________________________________ 600MRG mailing list Home: http://mailman.qth.net/mailman/listinfo/600mrg Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: https://www.qsl.net Please help support this email list: https://www.qsl.net/donate.html