--- i8cvs domenico.i8cvs@tin.it wrote:
The important of the point is that even if the lowest noise factor F1 do not correspond to the maximum gain the gain G1 obtained from it be sufficient to get a satisfactory overall noise factor Ft of the system as the formula for more stages in series is showing:
F2-1 F3-1Ft = F1 + --------+ --------- + .................. G1 G1xG2
This is in the Satellite Handbook, and the example calculations on page 11-2 were a big part of my decision to get the preamp. Example 3 is very similar to my situation, so it seemed reasonable that my overall NF would drop noticeably. Yes, the noise as displayed on the S-meter is about 5 S-Units higher. However, the signal is even higher still. The net is that I turn my volume control down on SSB and have more readable audio. I haven't experimented with the RF gain control on FM yet to see if it lowers the noise floor and improves quieting.
Bob