[Yaesu] Filter Improvements for FT-1000D

[Joe Subich, K4IK]

Ed, 

> This is what I THINK I learned from your inputs (with my little
> interpretations thrown in):
> 
> 1.  All filter slots in the 1000D Main Rx are fully populated
>      with good filters; and the only substantial reason to change
>      is if you don't like the factory BWs.  (If I could have any
>      four SSB/CW BWs I wanted--and if I wasn't concerned
>      about cost or button labels--I would probably go for
>      2.8/2.0/1.0/0.4, vs. the standard 2.4/2.0/0.5/0.25.)
> 
> 2.  The 1000D Sub Rx has NO standard filter for the CW
>      position, and a poorly-regarded Murata filter for SSB-type
>      BWs.  The CW filter slot can be populated either with
>      the optional Yaesu filter, or a slightly narrower-BW Inrad.
>      A replacement for the Murata SSB filter is neither plug-in
>      nor solder-in, but can be "kludged" in.
> 
> 3.  An Inrad kit has been announced to replace the 1000D
>      first IF (aka "roofing") filter with a 4 kHz BW filter.
>      (The stock filter BW seems to be unknown, but is probably
>      15 to 20 kHz.)  Making this change would significantly
>      sharpen up the SSB/CW performance, while degrading
>      broadcast AM, and nuking the FM mode.  (IMO, the latter
>      is not very practical anyway, because of no PL tone capability.)

In general you are correct.  However, I have not noticed any significant 
loss of fidelity when listening to broadcast AM with the roofing 
filter in my Mark V - particularly if I tune slightly high or low
(+/- 1 or 2 KHz).  The filter for my FR-1000D should be here this 
week and I hope to have a chance to check it out next weekend. 

> A question:  Where does the 6 kHz BW for the AM mode come
> from in the 1000D?  If it's something squishy like a 4-pole Murata,
> then my ideal "roofing" filter might be something like a SHARP
> 8 kHz or so.  This would yield excellent AM performance, and
> possibly usable FM, while still significantly improving SSB and
> CW close-in IM .  (This is based on the assumption of 15-20 kHz
> BW for the stock "roofing" filter.)  Alas, I don't expect Inrad to
> whip up one of these just for me!  ;-)

The 6 KHz selectivity is generated by CF-2002 (SLF-D6Y) a 6 KHz 
ceramic filter in the 455 KHz (3rd) IF.  I have not looked at 
it to see who made it or check the specs.  However, I expect it 
is relatively "sloppy."  

> And here's an embarrassingly basic question:  Why does one
> NEED higher performance in the Sub Rx?  Diversity reception?
> Better timing for calls in pile-ups, when working split?  I can't
> remember doing anything with my Sub Rx, other than checking
> to see if it works.

Upgrading the performance of the sub-receiver makes it useful for 
in band spotting during contest operation. One can alternate QSOs 
between the main and sub receivers or hunt for multipliers on the 
second receiver.  

73, 

   ... Joe, K4IK 
  

> 
> ----- Original Message ----- 
> From: "Joe Subich, K4IK" <k4ik at arrl.net>
> To: "'Hans Remeeus'" <hans at remeeus.nl>; "'Ed Senior'"
> <eseniors at earthlink.net>
> Sent: Monday, May 09, 2005 4:33 PM
> Subject: RE: [Yaesu] Filter Improvements for FT-1000D
> 
> 
> >
> > Hans,
> >
> > > Another filter suggestion for Ed could be:
> > >
> > > 2800 Hz Inrad filters instead of the 2400 Hz filters.
> > > 2400 Hz Yaesu filters (as standard mounted, but now installed
> > >    in the optional 2000 Hz SSB filter slots).
> > > 1000 Hz Inrad filters instead of the 500 Hz filters.
> > > 500 Hz Yaesu filters (as standard mounted, but now installed
> > >    in the optional 250 Hz CW filter slots).
> > >
> > > This needs some soldering, but saves you money.
> >
> > As long as one were not a SSB contester this would be the
> > way to go:
> >
> > INRAD/INRAD  2800/2800 (2800 Hz @ -6 dB, 3600 Hz @ -60 dB)
> > INRAD/INRAD  2100/2100 (2100 Hz @ -6 dB, 2700 Hz @ -60 dB)
> > INRAD/INRAD  1000/1000 (1000 Hz @ -6 dB, 1300 Hz @ -60 dB)
> > INRAD/INRAD   400/ 400 ( 400 Hz @ -6 dB,  580 Hz @ -60 dB)
> >
> > Unfortunately, there is probably no market for either the
> > stock '2400 Hz' pair or 8215 KHz 500 Hz filter (the optional
> > '2400 Hz' 3rd IF filter (XF-455-262-01) could be used to
> > replace the Murata filter in the sub-receiver).  One could
> > probably sell the 2000 Hz and 250 Hz filters (they are current
> > options for the Mark V and Field) and do the following at
> > minimum cost:
> >
> > INRAD/INRAD  2800/2800 (2800 Hz @ -6 dB, 3600 Hz @ -60 dB)
> > Yaesu/INRAD  2600/2100 (2160 Hz @ -6 dB, 3200 Hz @ -60 dB)
> > INRAD/INRAD  1000/1000 (1000 Hz @ -6 dB, 1300 Hz @ -60 dB)
> > Yaesu/INRAD   500/ 400 ( 410 Hz @ -6 dB,  700 Hz @ -60 dB)
> >     or
> > Yaesu/Yaesu   500/ 500 ( 500 Hz @ -6 dB,  750 Hz @ -60 dB)
> >
> > The tradeoff here is slightly poorer skirt selectivity
> > (shape factor) with two of the options.
> >
> > > However the new Inrad Roofing Filter would be my first choice
> > > to install!
> >
> > Without a doubt ... along with W8JI's 'plug in' noise blanker
> > and key click mods (http://www.w8ji.com/keyclicks_1000D.htm).
> >
> > 73,
> >
> >    ... Joe, K4IK
> >
> >
> >
> 
>