Changes in propagation give huge changes in signal strength.
WSPR has a SNR that can act as an S-meter.
But if you want to compare WSPR spots, you also have to take
into account the output power of the transmitter.
WSPR Propagation Analysis
I use the calculated lowest possible power
in milliwatt of each WSPR spot, when
- the spots are all made over the same distance
- the spots are made with different power.
the better the propagation.
Solid copy
The SNR of a WSPR signal can be as low as -33 dB.
But a WSPR signal that is received with a SNR of -29 dB will be a solid copy.
Calculated Lowest Possible Power
A signal with an SNR of -19 dB is 10 dB stronger, can be reduced with 10 dB
(1/10th of the power) and still be solid copy, but then also with a SNR of -29 dB.
Calculated Lowest Possible Power
A signal with an SNR of -19 dB is 10 dB stronger, can be reduced with 10 dB
(1/10th of the power) and still be solid copy, but then also with a SNR of -29 dB.
The better the propagation, the stronger the signal and the higher the SNR will be.
The more the power can be reduced and the lower the Lowest Possible Power will be.
But the frequency must be clear, to actually receive a signal with the Lowest Possible Power.
Hallo Bert, bedankt voor het mooie overzicht. Ik denk dat 1 watt een mooi beginpunt is voor WSPR en alle andere digitale modes. Meer is niet echt nodig. 73 Paul
BeantwoordenVerwijderenHello Paul, thank you for the comment. WSPR with 1 W can be compared with 20 W in CW. I often use 400 mW in CW which can be compared with 20 mW with WSPR.
VerwijderenI very much like the WSPR activity of Julian G4ILO with 20 mW and 1 mW. In a following WSPR Propagation Analysis I will compare 1 mW and 20 mW. 73, Bert