A current posting paints a totally incorrect picture of the relationship
between HF and VHF/UHF filtering methodologies.
A typical VHF repeater TX runs 50 -110 watts and the spacing
between TX and RX is 600 kHz. At UHF/450 the spacing is
5 mHz. (I'm a career two-way radio technician and have been
the repeater coordinator for Montana for 30 years.)
The set of six 160 - 10 meter bandpass filters that I use for HF
contesting and DX-peditions would all fit in the case of a K2 or
K3 and do function perfectly well in the same room with several
multi-op stations with KW transmitters. SO2R is the proverbial
"piece of cake". In addition, there are dedicated RF input limiters
available for the antenna inputs of radios if one wants additional
protection or doesn't have bandpass filters.
There is little, if any, relationship between the resonant cavity type
of band-pass, band-notch technology used in VHF/UHF duplexers
and the capacitor/inductor technology used in HF band-pass filters.
73! Ken Kopp - K0PP
[EMAIL PROTECTED]
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