The Keysight N9961B FieldFox is a portable handheld RF analyzer delivering spectrum analysis, vector network analysis, and cable/antenna characterization across 9 kHz to 44 GHz. Built for field service technicians and RF engineers, it combines ±0.2 dB amplitude accuracy with real-time spectrum analysis up to 120 MHz gap-free bandwidth. The instrument captures intermittent signals and supports interference detection, noise figure measurement, EMI analysis, and pulse characterization through configurable software options. VNA capabilities enable full 2-port reflection and transmission measurements, while time-domain reflectometry and TDR cable analysis pinpoint faults in transmission lines. Optional over-the-air measurement modes support 5G NR and LTE characterization. GPS/GNSS geolocation, I/Q data capture, and indoor/outdoor mapping extend utility for field deployment and drive-test applications.
Technical Specifications
Frequency Coverage:
• 9 kHz to 44 GHz (usable down to 5 kHz)
Amplitude Performance:
• Amplitude accuracy: ±0.2 dB overall (typical)
• Display average noise level (DANL): −163 dBm @ 2 GHz; −154 dBm typical
• Third-order intercept (TOI) @ 1 GHz: +5.1 dBm
• Spur-free dynamic range: >104 dB
• Output power: up to 6 dBm typical
Spectral Purity:
• Phase noise @ 1 GHz:
– 1 MHz offset: −125 dBc/Hz
– 10 kHz offset: −114 dBc/Hz
– 30 kHz offset: −114 dBc/Hz
Attenuation:
• Standard attenuator range: 40 dB
• Standard attenuator step: 5 dB
– Key Features
• Real-time spectrum analysis with 120 MHz gap-free bandwidth
• Intermittent signal capture and spectrogram analysis
• Full 2-port VNA with return loss and VSWR measurement
• Time-domain reflectometry for cable characterization
• Analog demodulation (AM/FM) and tune-and-listen capability
• Field strength, noise figure, and EMI measurement modes
• Over-the-air 5G NR and LTE analysis
• I/Q data streaming and signal monitoring
• GPS/GNSS receiver with geolocation and timestamping
• Field-swappable battery architecture
– Typical Applications
• RF/microwave system maintenance and troubleshooting
• Communication system commissioning and site surveys
• Radar and electronic warfare signal characterization
• Antenna and transmission line fault location
• EMI/RFI source identification and mapping
• 5G and LTE network drive testing
– Compatibility & Integration
• USB power sensor support
• I/Q streaming for external signal processing
• Channel scanner and extended range transmission analysis modes
• GPS/GNSS integration for temporal and spatial correlation
