For example: Agilent E4440A or Anritsu 68369
Transmission Test Kit
Keysight / Agilent 85046B
S-Parameter Test Set, 75 Ohms, 300 kHz to 2 GHz
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Manufacturer: Keysight / Agilent
Keysight / Agilent 87511B
S-Parameter Test Set, 75 Ohm 100 KHz- 500 MHz
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Manufacturer: Keysight / Agilent