[TenTec] Question on OMNI VI Filters

[DW Holtman]

Hello,

I recently picked up an Omni VI Plus. I really enjoy using it, full 
sized buttons, heavy stable tuning knob etc, all this on top of great 
performance.

Now back to my question. On the front panel there is 5 filter push buttons.

1.8   500   250   N1   N2

Looking at the manual, there is 4 filters that can be installed on the 
6.3MHz IF board. It already comes with a 2.4KHZ, a 1.8, 500 and 250 can 
be added to correspond to the first three filter select buttons.

The manual says that only one filter can be installed on the 9MHz 
mixer/IF board. If only one filter can be installed, why is there two 
narrow filter select buttons (N1 and N2)?

Now I have the 1.8 and the 500 installed and I'm thinking about finding 
a model 217, 500 Hz filter to install on the 9 MHz board, and possibly a 
250 Hz to put in the 6.3MHz board.

Thank you,
DW Holtman