[TenTec] Which filters

[Jim Reid]

The discussion continues:

> Well, being as the next Omni I get will be my first Omni since the series
C
> days, I know I don't have a leg to stand on.. It just seemed at the moment
> that the INRAD filters were running away in the opinion polls..

> >I think the TT filters are very good, and don't
> >necessarily need "fixing".

Aloha again,

Well,  as I listed all the INRAD's in my Omni,  I should say I
agree that the TT's are very good,  and yes,  my additions/
substitutions/rearranging were specifically for my own reasons.

However,  there is a NEED is some new Omni VI+ rigs to do
something about the 9 MHz strip front end "Standard"  2.4 kHz
filter.  Both transmit and rcv signals pass through this filter!
And TT's filter vendor production tolerances are such that,
in some new Omni's,  the filter skirt is too narrow/offset from
spec position.

The result is a "hard" sounding initial CW wavefront;  W1AW's
20 meter CW signal on 14047.5 has been a specific example
of the sound of this sort of "troubled" CW note.

Much was made of this, and a couple of different solutions
were found and discussed about one year ago on this TT
reflector.  A reflector archive search of Aug.,  Sept. and
Oct of '98 well find this information.

Someone found that widening this front end,  9MHz IF filter
which is ALWAYS in line,  both xmit and rcv,  would be
a fix for this transmitted CW note problem.  INRAD was
asked to make a special run of 2.8 kHz BW,  9 Mhz
centered IF filters;  many of us subscribed to this initial
run -- and it seems to have been a very satisfactory solution
to the "thumpy" or harsh CW onset sound in some Omnis
in which the "standard"  TT 2.4 kHz 9 MHz filter was just a
tad too narrow.  Does your Omni have this problem?  Have
a CW QSO with some one and ask how your note sounds.
Your rig may be fine,  it only occurred in some of the production
units,  and may be fixed in production  now,  I do not know.

Later,  again at someone's request,  INRAD made the matching
2.8 kHz filter for the 6 MHz IF strip (Passband tuning strip).  This
was done to provide a wider ( more HI FI maybe)  bandwidth for
SSB  signals.  I have these wider filters,  and very much enjoy
the wider BW SSB audio sound -- again my personal choice.
And I have a very nice CW note for that mode.

Hope this info helps some in their decisions.

73,  Jim,  KH7M



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