400 to 4000MHz frequency range.
Excess Noise Ratio is 15.6 dB, ±0.6 dB.
Maximum SWR (50 ohms nominal) is 2.0 (ON), 3.0 (OFF).
The Agilent HP 349A UHF Noise Source consists of argon gas discharge tubes in Type N coaxial configuation for automatic noice figure readings,
Specifications & Attributes (Noise [Source/Figure Meter])
400 MHz - 4000 MHz