[CQ-Contest] SDR station antenna integration (was Paralleling band pass filters)
shristov
shristov at ptt.rs
Thu Dec 30 14:26:47 PST 2010
<k3mm at verizon.net> wrote:
> ... most bandpass filter designs are just that...a high impedance everywhere but in the passband
Away from the passband, the ONLY thing that is SURE about filter input
is a high reflection coefficient, not any particular level of impedance.
High reflection coefficient may mean any of these:
short, open, low L, medium L, high L, low C, medium C, high C, etc.
Ordinary filters are not designed to present any particular level of
impedance (away from the passband), only a high reflection (high SWR).
An existing filter designs should be simulated and/or measured
before contemplating parallel connection.
73 & Happy New Year 2011,
Sinisa YT1NT, VE3EA
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