in the gnuradio-example

Hi all,
I use the in the gnuradio-example to do the
spectrum sensing. The gain is 45dB. I got the mag_squared of the fft
output ( I think that I can treat it as power. I would like to
draw the spectrogram. Does any one know the unit of the in the ? I use the 10*log(mag_squared) and the results
are between 50-100dB. I think something is wrong. The value is too
Thank you!