How does the 10 dB noise figure of HMC1023 change as the gain of the VGA changes?
Note that there are only two discrete gain settings for the HMC1023 - nominally 0 dB (min. gain) and 10 dB (max. gain), as set by bit  of Register 02h, but no possible gain settings in-between. Table 1 of the datasheet (p. 2 in v01.0113) lists noise figure as a function of these two gain states and two exemplary source impedance values (100 Ohm and 1 kOhm), ranging between 12 dB and 25 dB. The front page of the datasheet advertises 10 dB as highlighted by Eamon - presumably in high gain, but at what input impedance?