The Keysight FieldFox Handheld Analyzer is a ruggedized, battery-powered handheld test instrument designed for RF and microwave measurements outside the laboratory environment. The FieldFox family covers frequency ranges from 4 GHz through 54 GHz across multiple model variants, and each unit is built to withstand harsh working conditions while delivering measurement performance the datasheet positions as correlating with high-performance benchtop instruments. The instrument is intended as a field-capable platform for measuring cables, antennas, filters, amplifiers, and modulated RF signals.

FieldFox is positioned by the datasheet for cable and antenna test on cellular and microwave infrastructure, 5G deployment and field testing, satellite and radar coverage verification, beamforming verification with phased array antennas, radar and electronic warfare systems diagnostics, and field signal monitoring with wideband IQ capture. The datasheet specifically identifies hardware installation and maintenance, over-the-air signal quality verification, interference hunting, and characterization of pulsed RF signals as application areas the instrument is designed to address.

ValueTronics stocks and tests the FieldFox handheld analyzer family at our 20,000 square foot secure warehouse at 1675 Cambridge Drive in Elgin, Illinois. Every unit we list passes through our in-house performance verification process before shipping, and our condition reports document what our technicians measured rather than what a prior seller described. We have been supplying test and measurement instruments to engineering teams, defense programs, university labs, and field service operations since 1992, and our breadth across more than 120 manufacturers means we can pair a FieldFox with the cables, calibration kits, antennas, and companion instruments a complete field measurement setup typically requires.

Brand Heritage

Keysight Technologies was spun off from Agilent Technologies in 2014, and Agilent itself was created in 1999 when Hewlett-Packard separated its test and measurement business from its computing business. The HP–Agilent–Keysight progression means that FieldFox is a direct continuation of the Hewlett-Packard test and measurement engineering legacy, and calibration support, application engineering, and the broader product ecosystem are now provided under the Keysight name.

Compare Other Models in This Series

The FieldFox family is organized into two parallel product lines that share the same handheld chassis and user interface. Combination analyzer models — covering Cable and Antenna Test, Vector Network Analysis, and Spectrum Analysis — use model numbers in the N991x, N993x, N995x, and N912C ranges. Dedicated Spectrum Analyzer models use model numbers in the N993x, N996x, and corresponding C-series ranges. Both lines span frequency coverage from 4 GHz through 54 GHz, allowing a buyer to match the instrument's frequency ceiling to the highest frequency the application requires.

Across the family, the datasheet identifies three series generations: the legacy B-Series (now discontinued for several models and replaced by the C-Series equivalents), the current C-Series, and the newly introduced D-Series. The D-Series adds 120 MHz IQ streaming bandwidth, a Linux operating system, SFP+ 10-Gigabit Ethernet interfaces, a touchscreen for file management, and an enhanced DC power supply output. The C-Series N9912C in particular is positioned as a fully software-defined analyzer whose frequency coverage and instrument personality (CAT, VNA, or SA) are selected at purchase and upgradable by software license.

Each FieldFox model on this page is its own product listing with condition-matched pricing. Every new FieldFox unit is selected and prepared per the condition standards described on the listing, and the model variants in the comparison table below reflect the different frequency ceilings and feature sets available across the family.

The most consequential difference between FieldFox models is the maximum frequency. The N991x and N993x combination and spectrum analyzer models cover up to 4, 6.5, 9, 10, 14, 18, and 26.5 GHz. The N995x and N996x models extend coverage to 32, 44, 50, and 54 GHz, with the highest-frequency 54 GHz models (N9953 and N9963) using 1.85 mm test port connectors. The 26.5 GHz N9918 and N9938 models, and the 32 GHz and above models, use 2.4 mm or 1.85 mm connectors; lower-frequency models in the family use Type-N (female) or 3.5 mm (male) test ports as printed on each model's port labeling.

Beyond frequency coverage, models differ in their base instrument personality. Combination analyzers (N991x, N993x, N995x at the top of each frequency tier) include CAT and VNA capability as the base function with spectrum analysis available as an option. Dedicated spectrum analyzer models (N993x, N996x in the lower row of each frequency tier) include spectrum analysis as the base function and do not include the full VNA personality, although Option 320 provides reflection measurements including return loss and VSWR. The C-Series N9912C uniquely allows the buyer to choose CAT, NA, and/or SA personalities at the time of purchase through the CA, NA, and SA option codes, with frequency upgrade available via the N9912CU upgrade product.

Additional differences in specifications beyond the few shown above are not listed here — see each model's full specifications below.

Product Core & Specifications

Please review the Manufacturer's Data Sheet to verify published specifications. Feedback on this webpage is always welcome — please reach out to your Test Architect at any time for questions or concerns. Thank you, we truly appreciate you being our customer.