[1000mp] Re: New INRAD roofing filter Kit for FT1000MP

[Joe Subich, K4IK]

> The dynamic range listed in the specifications for my 
> FT-1000MP indicate a dynamic range of 108 dB (@50 kHz, 
> 500 Hz BW, RF amp off)
> 
> If George is claiming a dramatic improvement  of the Dynamic 
> Range: 97.5dB @3kHz spacing and 100.5dB @standard 5kHz spacing.
> 
> How can I make a fair comparison when the same standards are 
> not employed?

That's the entire problem ... Yaesu is only providing specs 
for wide spaced dynamic range (when did signals at the top 
of the band effect you when you were working at the bottom 
of the band?).  The FT-1000MP and most other modern rigs fall 
apart when the interfering signals get closer than about 10 
KHz away (within the 15 - 20 KHz wide "roofing" or front-end 
filter).  It is this problem that George's modification 
addresses (just like the Sherwood Engineering 600 Hz 1st IF 
filter for the R4C 25 years ago).  

The only way you can make a fair comparison is to note how 
much the "phantom signals" generated by mixing products from 
signals 5 - 10 KHz away go down with the new roofing filter 
installed.

73, 

   ... Joe, K4IK