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
>
>
>
> --
> FAQ on WWW:
> http://www.contesting.com/tentecfaq.htm
> Submissions: tentec@contesting.com
> Administrative requests:
> tentec-REQUEST@contesting.com
> Problems:
> owner-tentec@contesting.com
> Search:
> http://www.contesting.com/km9p/search.htm
>
>
_________________________________________________________
Do You Yahoo!?
Get your free @yahoo.com address at http://mail.yahoo.com
--
FAQ on WWW: http://www.contesting.com/tentecfaq.htm
Submissions: tentec@contesting.com
Administrative requests: tentec-REQUEST@contesting.com
Problems: owner-tentec@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|