First, note that these opinions are mine, and based upon my experiences and
research. I will always defer to someone who is more knowledgeable.
Re cascading identical bandwidth filters without using the PBT control, I
don't see any practical benefit to this for wideband modes like SSB. Think
of it as having two identically-sized windows, one right in front of the
other. You are going to be able to see the same thing whether the outside
window is twice as wide or the same width as the inside window. Now, in the
radio (as opposed to in the window analogy) the 9 mhz filters are before the
AGC so theoretically having two 1.8 khz filters cascaded and centered on the
same frequency might buy you a little less AGC pumping on strong adjacent CW
signals, but it would be the extremely rare QSO with SSB interference where
you could tell the difference.
Having a 2.8 khz and a 1.8 khz filter in the 9 mhz slots seems to be too
much of a duplication. Far better to have a 500 hz filter for CW (if you
like to operate mostly CW) or for RTTY (if you are an SSB and PSK fan and
don't do much CW) and then have the 2.4 or 2.8 khz filter in the 'wide'
slot.
This reply is based somewhat on the fact that you indicated you have/are
planning to get an Omni V. Having a VI+ gives you the extra 9 mhz slot.
The one filter selection that makes sense if 'hi-fi' SSB is important to you
but not at the expense of selectivity via a narrow 9 mhz filter would be to
change out both 2.4 khz filters for the Inrad 2.8 khz filters... and leave
the rest of them at the Ten-Tec-suggested widths (1.8/.5/.25 6 mhz, your
choice of 500 hz 9 mhz).
Hope this helps,
- jgc
John Clifford KD7KGX
Heathkit HW-9 WARC/HFT-9/HM-9
Elecraft K2 #1678 /KSB2/KIO2/KBT2/KAT2/KNB2/KAF2/KPA100
Ten-Tec Omni VI/Opt1
email: kd7kgx@arrl.net
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