[Yaesu] Filter Improvements for FT-1000D

[Ed Senior]

Hi again, Hans and Joe... and any others interested in this topic.

Many thanks to you two for your very helpful comments.

I had to be away from the NG for a few days, but I have a few
(belated) follow-ups:

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.)

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!  ;-)

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.

73 all around,

Ed, W6LOL

----- 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
>
>
>