The Keysight N9918B FieldFox is a ruggedized handheld combination analyzer covering 30 kHz to 26.5 GHz. As part of the FieldFox B-series, the N9918B integrates cable and antenna tester (CAT), vector network analyzer (VNA), and spectrum analyzer (SA) functionality in a single field-portable instrument, designed to bring laboratory-grade microwave measurement capability to environments where benchtop instruments cannot be deployed.

The datasheet describes the FieldFox as equipment built to be carried into the field, with type-tested compliance to MIL-PRF-28800F Class 2 covering operating temperature, storage temperature, operating humidity, random vibration, functional shock, and bench drop. The IP53 ingress protection rating per IEC/EN 60529 supports outdoor use in dust and light precipitation, and the instrument is type-tested for operation in explosive environments per MIL-STD-810G, Method 511.5, Procedure I. Typical applications supported by the datasheet's measurement coverage include cellular tower commissioning, antenna and cable verification, RF component characterization, and field spectrum monitoring.

ValueTronics International stocks, tests, and supports Keysight FieldFox analyzers including the N9918B from our 20,000 sq ft secure warehouse at 1675 Cambridge Drive, Elgin, Illinois. Every {{CONDITION}} N9918B leaving our facility has been inventoried, inspected, and prepared for shipment by our in-house team — not drop-shipped from a third party. Customers ordering through ValueTronics work with technical specialists who have direct knowledge of the FieldFox product family and the test applications it supports, with calibration documentation and ISO-traceable services available on request.

Brand Heritage

Keysight Technologies' test and measurement business traces its origin to Hewlett-Packard, which spun out its test and measurement, semiconductor products, and chemical analysis businesses as Agilent Technologies in 1999. In 2014, Agilent further divided its operations, with the electronic measurement business becoming Keysight Technologies. Engineers may encounter FieldFox documentation, accessories, and service materials referencing both Agilent and Keysight branding depending on the production date.

Compare Other Models in This Series

The FieldFox B-series spans two analyzer architectures across the 4 GHz to 50 GHz range. The N991xB combination analyzers (N9913B through N9918B) integrate CAT, VNA, and SA capability with 30 kHz lower frequency limits, while the N993xB signal analyzers (N9933B through N9938B) share the same upper frequency tiers but are positioned as spectrum-focused instruments. The N995xB and N996xB microwave series extends combination and signal analyzer coverage to 32, 44, and 50 GHz with a 300 kHz lower frequency limit.

Per the datasheet, all FieldFox models share a common physical platform — 292 x 188 x 82 mm, 3.34 kg with battery, 6.5" transflective color LCD-LED display, lithium-ion battery operation, LAN/USB connectivity, and MIL-PRF-28800F Class 2 environmental compliance. Models differ primarily in upper frequency limit, included measurement modes (combination vs. signal analyzer), and available connector type at the test ports.

Each new FieldFox model listed below is its own dedicated product page on ValueTronics with condition-matched pricing and availability. Use the comparison table to identify the model that fits your frequency range and measurement requirements, then navigate to the individual listing for ordering details specific to that unit.

The N9918B is the upper-frequency boundary of the N991xB combination analyzer line at 26.5 GHz. Per the datasheet, the 26.5 GHz models use 3.5 mm (m) test port connectors rather than the Type-N (f) connectors used on lower-frequency members of the series; Type-N is not offered on the N9918B combination analyzer. This connector choice supports the measurement performance and connector durability required at K-band frequencies.

Within the FieldFox B-series, primary differentiation across models is upper frequency limit: 4 GHz (N9913B/N9933B), 6.5 GHz (N9914B/N9934B), 9 GHz (N9915B/N9935B), 14 GHz (N9916B/N9936B), 18 GHz (N9917B/N9937B), 26.5 GHz (N9918B/N9938B), 32 GHz (N9950B/N9960B), 44 GHz (N9951B/N9961B), and 50 GHz (N9952B/N9962B). The datasheet specifies test port output power, dynamic range, DANL, phase noise, and amplitude accuracy separately for each model class.

The combination analyzers (N991xB, N995xB) include CAT and VNA capability with the spectrum analyzer offered as Option 233, while the signal analyzers (N993xB, N996xB) come configured as spectrum-focused instruments. Connector types vary by frequency tier: Type-N (f) for ≤18 GHz models, 3.5 mm (m) on the N9918B and optionally on N9938B, and 2.4 mm (m) on all 32/44/50 GHz models. Refer to the comparison table below for the differentiating specifications at each tier.

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.