Quote from AdminTC on 06/12/2020, 18:19

With the optional preamplifier, which can be activated via software key at any time, you get an additional gain of 10-20dB (depending on frequency) dropping the DANL below -170dBm/Hz.

Attached screenshot with two SPECTRAN V6 units running with and without preamplifier shows the huge difference: Only the preamplifier (left hand data stream) will show a lot of complex signals while the other unit (right hand data stream) without preamplifier only shows a red color noise floor without any signals (they are "hiding" below the noise floor).

If you need a low DANL and high sensitivity the preamplifier is a must have.