HP 5352B 005 010 46 GHz Microwave Frequency Counter
Input
2.4 mm male 500 MHz - 46 GHz, resolution 1 Hz
BNC f 10 Hz - 80 MHz, resolution 1 mHz, test picture at 1 kHz
BNC f 10 MHz - 525 MHz, resolution 1 mHz, test picture at 10 MHz
measured sensitivity -27 dbm at 40 GHz ( spec is -20 dbm )
has options
005 46 GHz extention 
010 high stability oven timebase, see picture of 10811-60211 ocxo