From 1988 HP Catalog :

The HP 4195A is a high performance, cost effective and intelligent analyzer with combined vector network and spectrum analysis capabilities. The frequency is covered from 10Hz through 500MHz with an excellent 0.001 Hz resolution for audio, baseband, HF, VHF and IF applications. It directly measures amplitude ratio, phase, group delay and spectrum level […]

The 4194A was replaced by the 4395A around 1998.

• Frequency: 10Hz to 500MHz, 1mHz resolution
• Power: -50 dBm to + 15 dBm, 0.ldB resolution
• Sweep Parameters: Frequency, power and dc bias level
• Sweep Types: Linear, log, cw, program and partial
• Output: 2 outputs
• DC bias level: ±40V, 10mV resolution

• Frequency: 10Hz to 500MHz
• Input: 4 inputs, 50 ohm nominal
• Resolution Bandwidth: 3Hz to 300kHz, 1 or 3 step
• Input Crosstalk: <= -100dB

• Dynamic Range: > 100dB
• Resolution: 0.00ldB Dynamic Accuracy (23 ± 5C), -30dBm R input: ±0.05dB @ -70dBm to -30dBm T input.

• Range: ± 180°
• Resolution: 0.01 °
• Dynamic Accuracy (23 ± 5C, -30dBm input): ±0.3° @ -70 to -30dBm T input.

• Range: 10ps to 500s
• Resolution: 10ps @ 3.6 MHz aperture
• Accuracy: depends on phase accuracy

• Mode: Normalization, 1 port partial cal, 1 port full cal and port extension.

• Measurement Range: 10 Hz to 500 MHz
• Resolution: RBW: 3 Hz to 300 kHz, 1-3-10 step
• Selectivity (60/3 dB): 4.5 for 3 Hz to 30 Hz, 9 for 100 Hz to 10 kHz, 8.5 for 30 kHz to 300 kHz
• Noise Sideband: <–100 dBc/Hz @ 1 kHz offset; <–90 dBc/Hz @ 100 Hz offset

• Measurement Range: –135 dBm to +20 dBm
• Accuracy: ±1.0 dB @ 50 MHz
• Linearity (23° ±5° C): ±0.1 dB @ –40 to 0 dB; ±0.2 dB @ –60 to –40 dB
• Frequency Response: ±1.5 dB

• Second Harmonic Distortion: ≤–70 dBc @ ≥2 MHz
• Residual Response: –110 dBm @ ≥100 kHz
• T.O.I. Distortion: ≤ –80 dBc @ ≥2 MHz
• Average Noise Level: Typically –140 dBm @ 10 Hz RBW, ≥2 MHz

• Sweep Type: Linear, log, cw, program and partial
• Sweep Mode: Continuous, single and manual
• Sweep Time: Approximately 3.5 sec @ 500 MHz span, 300 kHz RBW

• Number of Inputs: 4 inputs
• Impedance: 50 Ω nominal
• Damage Level: +30 dBm
• Attenuator: 0 to 50 dB, 10 dB step

TODO : link to manuals still available on Keysight, + upload here

• ROM 2.00, rev 8905 @KO4BB
• ROM 2.10, rev 9112 @KO4BB