Thread title changed to reflect reality!
Jon says:
>I would expect my FT-840 to have better receiver IM performance
One factor that is not appreciated widely is that the intermodulation
limited
dynamic range in a receiver (some call it 'Spurious Free Dynamic range' - it
is
2/3 of the difference in dB between the bandwidth dependent noise floor in
dBm and the input third order intercept point in dBm) and the phase noise
limited dynamic range need to be about equal. Having one greatly exceeding
the other is a waste of effort. This also means that a practical limitation
on how
much IMD performance a receiver needs is how much phase noise exists from
other transmissions on the band. I've heard a number of FT1000s on the band
that weren't too good - this on CW. So that could be a limit. Fortunately,
tube
PAs aren't generally too bad for wideband noise, but the wideband noise from
some solid state drivers leaves a lot to be desired.
73
Peter G3RZP
--
FAQ on WWW: http://www.contesting.com/ampfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|