[Yaesu] Filter Improvements for FT-1000D

Sun May 8 14:31:53 EDT 2005

Ed, 
> >
> > 2800 Hz Inrad instead of the standard 2400 Hz Yaesu
> > 2100 Hz Inrad as optional SSB
>> I take it you prefer leaning a bit more towards "high
> fidelity" audio, vs. maximizing selectivity.

Yes, Hans likes the higher fidelity audio on SSB <G>. Based 
on their part number, each of the Yaesu filters (8.215 MHz and 
455 KHz) are actually 2600 Hz wide at the -6 dB points. When 
cascaded, they yield 2400 Hz overall at the -6 dB points. 
> > 400/500 Hz Inrad as optional CW
>> I assume you feel the Inrad 400 outperforms the Yaesu
> 500; but another recent poster seems disappointed to
> find little difference.

This is an "apples to oranges" thing. The original FT-1000 
third IF filter option was a crystal filter. Yaesu's current 
offering for the MP/MKV/Field is a Collins mechanical filter - 
it is exceedingly wide (look at INRAD's curves as their Collins 
filter is identical to Yaesu's). The INRAD 400 or 500 Hz crystal 
filter has vastly superior skirt selectivity and I doubt that you 
will see a lot of difference (about 50 Hz based on the curves on 
the INRAD web site) between their 400 and 500 Hz units. 
I am replacing the 500 Hz Collins filter in the subreceiver of 
my Mark V with an INRAD crystal filter because the Collins 
filter is so sloppy and I will probably replace the 600 Hz 
six pole (crystal) CW filter in the subreceiver of my FT-1000D 
for the same reason. 
> > Sub Rx:
> >
> > 2800 Hz Inrad (wire-in) instead of the standard 2400 Hz Murata
> >
> Is "higher fidelity audio again the concern?

No ... here the stock 3rd IF filter is a Murata ceramic filter. 
Its skirts are quite sloppy (maybe four poles). The wire-in 
crystal filter does the same job as replacing the Murata ceramic 
filter in the main receiver as part of the "D" package. 
I would use the INRAD 2100 Hz filter for this purpose. 
BTW, the INRAD web site indicates the FT-1000D roofing filter 
is available (delivery at Dayton). Based on the results in my 
Mark V, I would make a roofing filter the first filter addition 
to an FT-1000/FT-1000D. 
My personal recommendations are: 
FT-1000D: 
----------
1) INRAD roofing filter 
2) INRAD 400 Hz CW filter for the sub receiver 
3) replace the Murata ceramic filter in the sub-receiver 
 with an INRAD 702 
4) add the optional 250 Hz 3rd IF filter if necessary.
 
FT-1000: 
---------
1) INRAD roofing filter 
2) INRAD 400 Hz CW filter for the sub receiver 
3) Replace the ceramic filter (SSB) in the 3rd IF 
 with an INRAD 715C (2800 Hz Crystal filter) or 
 the Yaesu XF-C if you can find it. 
4) Add the INRAD 400 or 500 HZ crystal filter to 
 the 3rd IF 
5) replace the Murata ceramic filter in the sub-receiver 
 with an INRAD 702 
6) add INRAD 1800 Hz and/or 250 Hz filter pairs depending 
 on your own operating habits. 
73, 
 ... Joe, K4IK