[TenTec] INRAD 2.4khz 10 Pole Filter

[N1EU]

Wow - didn't take long for Jim to cut to the chase 
:-)

Imp't question as Jim points out is: Is the INRAD 756
okay for the first 9Mhz slot?

Also need to verify what I saw - can someone else slip
a 756 in the first position and try to duplicate what
I described in previous email?

Normally I would have the 756 in the optional filter
position with the INRAD 2.8 in the standard position. 
But I was hoping to optimize the Omni for a cw-only
effort in next weeks's IARU test so want to load up
the 500s and 250s (which really do a fabulous job,
BTW) and use the 756 ahead of them.

Tnx & 73,
Barry  N1EU

--- Jim Reid <jreid@aloha.net> wrote:
> 
> Aloha,  Barry just wrote:
> 
> > I installed the INRAD 2.4khz 10 pole filter in the
> > standard first (non-switched) 9 Mhz position,
> > replacing the Ten Tec 2.4khz filter.  I find that
> the
> > INRAD filter has less loss than the Ten Tec, with
> the
> > result that with RF gain full clockwise, there can
> be
> > some feedback.  If anyone else has this filter
> > installed in that position, try this: disconnect
> the
> > antenna and crank the RF gain control (no filter
> > option switches engaged in either if).  In cw, my
> > audio starts to whistle and in usb starts a
> swishing
> > whistle.
> 
> I just tried Barry's suggested test.  Result:  No
> problem
> here,  hooray!  But,  wait,  just realized my set up
> is
> different,  or at least Barry's is different from
> what
> I thought George at INRAD had in mind.
> 
> Barry said he put the new 10 pole,
> 2.4 kHz filter there!!  That is not where that one
> is supposed
> to go,  as I understood the situation.  It  is the
> 2.8 kHz, INRAD
> #754 that is supposed to go up there.  That is the
> slot where
> you must remove the entire bottom cover from the
> Omni
> underside to get to it.  The 2.4 is to go in a slot
> under
> the small optional filter access "hatch".  I put the
> new
> 2.4 kHz INRAD # 756 into the first IF N-1 slot.
> 
> Maybe what Barry did is not correct?  Or maybe it
> should 
> work anyway?  Why not,  TT's standard in that slot
> is a
> 2.4kHz filter.
> 
> Perhaps Paul Christensen, W9AC, knows or can suggest
> what 
> might be going on.  I believe he  was one of the
> gurus 
> who came up with the 2.8 filter as the fix for the
> Omni VI+ 
> CW "thump", click,  or whatever solution.   The 2.8
> is supposed
> to eliminate a fab tolerance problem occurring in
> some
> of the TT standard units in that IF front end which
> clipped
> the leading edge of CW "pulses" during transmit.
> 
> But in my set up,  with all filters out,
> and only the new INRAD #754 in that very first
> position,
> there is no evidence of Barry's feedback problem.
> Can the gain through that front end filter be
> jumpered,
> as in the optional filter slots?  Maybe it is on
> high
> gain,  Barry;  just a guess.  Or,  perhaps there is 
> something else about the 10 pole filter that just
> won't work in that first slot replacing the TT
> "standard"
> 2.4 filter there.
> 
> 73,  Jim,  KH7M
> 
> 
> 
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