[1000mp] Roofing Filter

[Tod - MN]

>Does the S-meter reading for 50uV vary band-to-band?
> 
> -Brian n8wrl
> 

The S-meter reading does change from band to band. The shape of the curve
from S0 to S9 is essentially the same over a  single band when you change
the IF gain in menu 9-1 . I plotted the set of curves for my FT1000MP
showing the S0 to S9 values on 20 meters for various settings of the IF
gain. On 20 meters with S9 at -73dBm the value for S0 is -98 dBm  and  in my
case this happened with an IF gain setting of 10.

I found that an IF gain setting of 12 produced a curve on 20 meters that had
S0 = -104 dBm and S9 = -81 dBm . The ambient atmospheric noise would
sometimes produce a single bar on the S-meter (when the band was not dead).
I prefer to have the noise just at the start of the S meter action rather
than worry about whether S9 is 50 uv. Please note that S0 on the meter is
considerably higher than the MDS which is on the order of -120 dBm or less.

Installation of the roofing filter seems to have moved the noise threshold
when the band is active somewhat lower than it had been before thereby
enabling one to work weaker signals more easily.



Tod, KØTO