Hi,
the precise number for the receiver could be the MDS or the sensitivity. It is measured at the receiver input.
MDS - the minimum discernable (or decodable) signal
Sensitivity - the signal that is a predefined number of SNR.
?
When it comes to your question as how it works on the air, how you can make the least possible QSO than you have to calculate more things.
- from you --> the correspondent
your: TX power, antenna efficiency, --- propagation, QRM, --- correspondent's: antenna efficiency, RX sensitivity.
- from him --> you:
his: TX power, antenna efficiency, --- propagation, QRM, --- your: antenna efficiency, RX sensitivity.
?
In the QSO all these are in series, so whatever parameter fails - no answer, no QSO.
--
73 Bojan S53DZ
