[1000mp] Inrad filter questions

[Ron Kenwood]

First the roofing filter. I installed it and tested with my Elecraft XG1
at 50 microvolts. Before the install, 1 red bar above S9. After, 2 red
bars above S9. When I switch in 6 db of attenuation, both red bars go
out. My completely unscientific SWAG would be 3 db additional gain. I
know that the extra gain moves me further away from the  mythical 50
microvolts = S9.

The Inrad instructions say don't reduce the 9-1 gain unless you are
removing the 70 MHz mod.

Do I benefit from the extra gain, or does potential noise reduction of
lowering 9-1 gain outweigh any benefit?

Second, I am considering ordering a 400 Hz Inrad filter for the sub 
receiver. I happened to read the sub receiver section of the manual 
(strictly an accident and not consistent with my normal behavior) and it 
says the sub receiver narrow filter is switched automatically by mode, 
as in AM, SSB & CW. Does this mean that it doesn't work when using 
RTTY(FSK)?


Ron, W3ZV