Hi, In the Amplifier component (found in lumped components), the noise figure seems to be calculated on the output of the amplifier. I think it should be on the input since the noise figure changes now as you vary the gain.
With a gain of 10 and NF of 7dB, it gives a noise figure of 0.519dB instead. When the gain is 1, the noise figure is 7dB as expected.
qucs version: trunk