Why use a narrow filter when the waterfall covers 2500 Hz?
You will get the best performance with a ‘matched filter’, i.e. a filter which has a bandpass matched to the bandwidth of the signal. Only then the S/N ratio will be optimal. Using a wide filter for psk is nice when all signals in the passband have the same strength (alll are strong). Agc action and receiver overload will kill weak signals. Here is an example from 10 MHz, the signals on the high side of the spectrum are the APRS 300 Bd Packet channel and the new ‘robust packet’ signals…
