TopBand: TS-870 IF Filters and more

[km1h@juno.com]

I understand that a few W6's have added real 8 pole filters to the 8.8MHz
and 455KHz IF's of the TS-870.
Does anyone have any info on who they are or any published info? 

>From the limited experience I have had with a borrowed 870 it would be a
great rig with those filters.
I was not impressed with a TS-570D that I had on loan for a week. The
audio DSP was better than the DSP-59+ but the lack of the IF DSP of the
870 was a very noticable difference.  I use Beverages for RX on 160/80
and live in a quiet rural area; so the audio NR function of the 570 was
not tested against man-made QRN. It also did not appear to function at
all against weak to moderate static. 

The 870 is the rig that I WANT to like and possibly replace the highly
modified TS-940.

As I mentioned here several months ago I sold my FT1000D and preferred a
pair of  modified 940's as the way to go for my particular situation on
HF.  I also sold the DSP-59+ as being way too annoying to use. I have not
tried newer audio DSP boxes since I feel that IF DSP is the proper way to
go. 

What I would really prefer is an outboard IF and audio DSP unit that
would simply tap off from the 455KHz IF of the TS-940 (or ANY rig) .  It
would then provide all the TS-870 functions from that point out to the
headphone jack.  This might be a profitable niche market for someone to
look into.  PC based maybe???

Any comments?

73....Carl   KM1H

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