Hi Jim and the group:
Just a few corrective comments to your interesting discussion
about the optimal filter setup for the OMNI VI+.
First, the INRAD filters are indeed available, I bought a pair
last month. The webpage maybe isn't showing it right now?
That would surprise me because that is where I ordered mine,
but heck, webpage maintenance isn't always up to par!
Second, lower loss in IF filters DOES indeed make a difference.
The INRAD filters, for $20 more than the Ten Tec filters, spec
out with lower loss. If there is lower loss in the IF chain,
there is more signal for the AGC to use in the end. AND, when the
AGC is out of slack, the lower loss will get you a few db more
down into the noise floor (weak signals).
I am not sure about the effect of shielding (the INRAD filters
are in metal cans, the Ten Tec - Network Sciences filters are
crystals soldered to a board), I have not had any problems with
either filter that I would attribute to such conditions.
However, good shielding is just plain good practice, I appreciate
that.
I still have a set of the Ten Tec filters in my Corsair I, but
keep the INRAD filters in my OMNI VI and they just plain impress
my ear a bit more, I believe (not objectively tested) that there
is a bit less ringing too. The INRAD filters spec out with a
better shape factor (steeper skirts) which should improve a bit
on an already very good receiver. It's a matter of $20 per filter
and the fact that they are Japanese made filters inside a
Ten Tec rig (shock :-).
Anyway, the Ten Tec filters clearly do not lack, I just find the
incremental improvement per dollar ratio to take me over to
the INRAD filters. Good luck, hope to work you on the air!
Clark
WA3JPG
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