Keysight (Agilent) N9951A FieldFox Handheld Microwave Analyzer, 44 GHz

The Keysight N9951A FieldFox Handheld Microwave Analyzer is a battery-operated, portable instrument for field testing up to 44 GHz. It combines cable and antenna analysis as standard with optional vector network analysis, spectrum analysis, power metering, and vector voltmeter capabilities. Weighing only 7.1 lb (3.2 kg), the N9951A delivers accurate measurements without warm-up delay, making it ideal for aerospace, defense, and telecommunications field operations.

Technical Specifications

• Cable and Antenna Analysis (CAT) and Vector Network Analysis (VNA): 300 kHz to 44 GHz


• Spectrum Analysis (SA): 5 kHz to 44 GHz


• Analysis Bandwidth: Maximum 10 MHz


• Real-Time Bandwidth: Maximum 10 MHz Performance Metrics:


• Spectrum Analyzer Accuracy: ±0.5 dB (no warm-up required)


• Trace Noise: 0.004 dB rms


• DANL @ 1 GHz: -159 dBm


• Third-Order Intercept (TOI) @ 1 GHz: +13 dBm


• Phase Noise @ 1 GHz: -113 dBc/Hz (1 MHz offset), -111 dBc/Hz (10 kHz offset), -108 dBc/Hz (30 kHz offset)


• Network Analyzer Dynamic Range: 100 dBm Output Power:


• Maximum Leveled Output: Up to 0 dBm


• VNA Default Output: -15 dBm


• Low Power Output: -35 dBm typical, -38 dBm nominal (500 kHz to 10 MHz)

Key Features

• Simultaneous measurement of all four S-parameters


• Time Domain Reflectometry (TDR) and Distance To Fault (DTF) in single sweep


• Dual integrated ports with remote control and SCPI support


• Configurable power settings: High, Low, and Manual modes


• Average and pulse power measurement via USB sensor


• RF pulse testing with peak power capability


• Frequency-offset and swept-frequency analysis

Standard and Optional Capabilities Standard: Cable and Antenna Analyzer (CAT) Optional Modules:

Vector Network Analyzer (VNA)

Spectrum Analyzer (SA)

Built-in Power Meter

Vector Voltmeter

GPS Receiver

Typical Applications In-situ cable and transmission line testing, antenna characterization, component verification, field troubleshooting, and maintenance across aerospace, defense, and telecommunications infrastructure.

Physical and Power

• Weight: 7.1 lb (3.2 kg)


• Power: Rechargeable Li-ion battery with AC/DC adapter


• Included: Soft carrying case with backpack, LAN cable, localized power cord