Agilent/Keysight N9961A

The Keysight N9961A FieldFox is a handheld microwave spectrum analyzer engineered for field deployment in demanding environments. It delivers accurate spectrum analysis, cable and antenna testing, and network analysis without warm-up delay. The instrument captures intermittent signals across a 10 MHz gap-free real-time bandwidth and characterizes radar pulse profiles with precision.

Its dual 2.4 mm RF input ports support over-the-air measurements for 5G and LTE, I/Q data capture, noise figure analysis, and field strength measurement. GPS/GNSS integration enables geolocation and timestamping of events. The rugged, fan-free design with anti-glare 6.5-inch display and backlit keypad performs reliably in harsh field conditions.

Technical Specifications

Frequency Range: 9 kHz to 44 GHz Spectrum Analysis Performance

• Amplitude accuracy: ±0.5 dB without warm-up


• Dynamic range: 96 dB in spectrum analysis mode; TOI >+15 dBm


• DANL: −138 to −108 dBm/Hz


• Phase noise: −111 dBc/Hz at 10 kHz offset


• Resolution bandwidth: 10 Hz to 5 MHz


• Real-time bandwidth: 10 MHz gap-free Measurement Capabilities


• Radar pulse profile characterization


• Intermittent signal capture


• Noise figure measurements


• I/Q data capture for RF signal analysis


• Over-the-air measurements for 5G TF and LTE


• Field strength measurement with spectrogram display


• AM/FM tune and listen


• Built-in power meter with extended range transmission analysis (ERTA)


• Stimulus-response analysis RF Specifications


• Input ports: 2 (2.4 mm male connectors)


• Maximum input level: +10 dBm (0.15 dB compression 500 MHz–1 GHz); +10 dBm typical 0.10 dB compression (>1–26.5 GHz)


• Output power: up to 4 dBm


• IF output: 25 MHz bandwidth Physical & Power


• Dimensions: 292 mm H × 188 mm W


• Weight: 3.2 kg


• Display: 6.5-inch anti-glare LCD with LED backlight


• Power: AC or rechargeable Li-ion battery


• Design: Rugged, dust-free, no fans or vents

Key Features

• Dual-port architecture for simultaneous two-port measurements


• No warm-up required; immediate measurement capability


• GPS/GNSS for synchronized geolocation and timestamping


• Superior phase noise performance (−111 dBc/Hz @ 10 kHz offset)


• Backlit keypad and anti-glare display for outdoor operation

Typical Applications

• Field maintenance and troubleshooting on installed systems


• Radar pulse characterization and analysis


• 5G and LTE over-the-air signal verification


• Cable and antenna performance validation


• Spectrum monitoring with real-time signal capture


• Noise figure and transmission analysis

Compatibility & Integration

• Ethernet connectivity to 89600 VSA software on Windows PC or tablet


• USB power sensor support


• IF output port for external signal processing