Hi Guy's
Thanks for the interesting discussion on the state of the art in SDR
technology. This discussion does raise a few questions in my mind that I
would like to ask. To me it is a question of the theoretical as opposed
to the practical. Does it really matter if a receiver can hold up to a
80db over 9 signal 2 Khz away or is this just a theoretical exercise?
Would not the transmitted Phase Noise, IMD, and perhaps key clicks be
the limiting factor or am I wrong about this?
Is there is a point of no return where increased close in dynamic range
no long matters because modern transmitters simply can not or do not
transmit a signal that clean. If so, then has the K3 and the Perseus
reached that point of no return and the question of which one has a
better close in dynamic range is more of a theoretical then a practical
exercise.
I would think that with very strong signals (like 80 db over 9), the
more important number from a practical point of view would be at wider
spacings, as I would want to know if the receiver would hold up when I
move away from the phase noise and IMD of the transmitted signal. I have
a neighbor ham that I receive a very strong signal from. It would be
impossible to operate 2 Khz from him regardless of receiver performance,
but I do operate on CW while he is on SSB on the same band using the K3
and I do not hear a thing. In my case, wide spacing performance is
important to me, and is a concern that I have when considering
purchasing a Windows based SDR. When I see wide spaced numbers of
117-123, compared to the 140db plus of the K3, I feel that the wider
spaced number are the more critical numbers to look at, or am I wrong
about that?
73,
John, KD8K
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