What are the key differences between benchtop and handheld RF analyzers for field measurements?

Overview: This article explores how modern handheld RF analyzers compare with benchtop units. It highlights performance trade-offs, environmental considerations, and workflow adaptations for effective field measurements with a focus on Keysight's N9918B analyzer.

When selecting between handheld and benchtop RF analyzers, understanding the performance differences helps you make the right choice for your specific applications.

What Are the Key Performance Differences Between Handheld and Benchtop RF Analyzers?

Benchtop analyzers offer better dynamic range and sensitivity due to their stable power supply and controlled environment. This results in lower noise floors that allow you to detect faint signals near strong ones. However, modern handheld analyzers now offer dynamic ranges exceeding 100 dB and sensitivity with noise floors below -160 dBm, which comes close to mid-range benchtop capabilities. The spectrum measurement of the benchtop and handheld analyser is shown in Fig. 1.

Fig. 1 Spectrum Measurement of (A) MXA Benchtop Analyzer and (B) FieldFox Spectrum Analyzer. Source: TestWorld Inc.

Which is the preferred choice for high-frequency applications?

The absolute highest frequencies and widest analysis bandwidths remain available only on benchtop instruments. While earlier portable analyzers had frequency limitations, current handheld models cover wide ranges that often extend into microwave and millimeter-wave bands, up to 54 GHz or higher. This makes them suitable for applications like 5G testing.

How significant is measurement accuracy for your applications?

Both types require proper calibration, but they approach it differently. Laboratory calibration ensures high accuracy under ideal conditions, while field calibration corrects for the entire measurement setup, including cables and adapters, within the actual operating environment. Techniques like Short-Open-Load-Through and Through-Reflect-Line, along with automated Electronic Calibration modules, help maintain reliable on-site accuracy.

How Do Environmental Factors Influence the Choice Between Field and Benchtop Analyzers?

Field measurements present challenges that are vastly different from controlled laboratory settings. And yes, this is where handheld analyzers shine.

Handheld instruments are built for portability and resilience, often meeting standards like MIL-PRF-28800F Class 2. This means they can handle harsh temperature ranges from -10°C to +55°C, along with humidity, altitude, shock, and vibration. Their sealed enclosures often carry IP ratings such as IP51, IP53, or higher, which protect against dust and water conditions that would damage benchtop units (Fig. 2).

Fig. 2. the Rugged Nature of Portable Analyzers Helps in Harsh Conditions Such as Military Applications. Source: AspenCore

How long do you need to work without access to power?

Power considerations set these two analyzer types apart. Handhelds rely on batteries that provide 4 to over 8 hours of operation, often extended by power-saving features like auto-shutdown. Benchtop analyzers depend on AC power. An interesting bonus: battery power offers inherent isolation from AC line noise, which can benefit measurement stability in certain field scenarios.

How does size and weight also play an important role in selection?

Handheld analyzers are compact and lightweight, around 3 kg (7 lbs), with designs that prioritize ease of use. This includes readable displays for various lighting conditions, large backlit keys to operate with gloves, and secure grips. The smaller form factor allows access to confined spaces like equipment racks or remote tower locations that benchtop instruments cannot reach.

What Workflow Adaptations Make Handheld Analyzers More Effective in the Field?

Field conditions demand different approaches; handheld RF analyzers feature significant workflow and interface adaptations compared to their benchtop counterparts.

A major advantage is multi-functionality. Modern handheld analyzers integrate multiple test capabilities into a single device - Cable and Antenna Testing, Vector Network Analysis, Spectrum Analysis, power measurements, and sometimes Real-Time Spectrum Analysis or signal generation.

This consolidation allows for switching quickly between measurement modes and optimizing test sequences, reducing the need to carry multiple instruments. It can also perform Distance-to-Fault tests, S21 transmission measurements, and interference checks with one unit, saving time and minimizing connection errors.

How difficult is it to read a screen under bright sunlight?

User interfaces for handhelds are designed with field conditions in mind. Screen visibility is achieved through bright, non-reflective displays with adjustable brightness for sunlight or darkness. Operation is made easier with large, often backlit buttons and rotary knobs to use with gloves, complemented by intuitive touchscreens supporting gestures like pinch-to-zoom, as shown in Fig. 3.

Fig. 3 a Portable Analyzer With a Simplified User Interface. Source: Core Electronics

Data management also gets a field-friendly approach. Handheld analyzers offer on-device storage (USB/SD card), direct report generation in formats like CSV, S1P/S2P, PNG, PDF/HTML, and various transfer methods (USB, LAN). Remote control capabilities enable assistance from off-site experts and data synchronization. The rugged design protects both the instrument and your valuable data from harsh conditions, shock, and vibration.

How Does Keysight FieldFox Address Field Measurement Challenges?

Looking for a real-world example of these principles in action?

The Keysight FieldFox (Fig. 4) offers several features that tackle the challenges of field measurements head-on.

Fig. 4 Keysight's FieldFox Handheld Analyzers for Rugged and Portable Applications. Source: oemsecrets

It delivers laboratory-grade performance in a portable form, with a dynamic range of 90 dB for common laboratory applications. For environmental ruggedness, it complies with MIL-PRF-28800F Class 2 standards, operating from -10°C to 55°C with IP53 ingress protection.

Power optimization is another strong point, with 3.5-hour battery life and power consumption of only 15 watts. With reduced power consumption and an acceptable battery life, it is a good candidate for remote applications.

The multi-functionality aspect is well-covered, combining a cable and antenna analyzer, a vector network analyzer, a spectrum analyzer, real-time spectrum analysis, and power measurements in a single instrument. This eliminates the need to carry multiple field devices.

Workflow adaptations include features like Indoor/Outdoor mapping capabilities, an intuitive interface visible in various lighting conditions, and data logging with GPS tagging - all designed to make field work more efficient.

Summarizing Keypoints

• Selecting the right RF analyzer means balancing performance against field requirements. Modern handheld units now deliver near-benchtop performance while excelling in harsh environments where lab equipment fails.

• Today's field analyzers offer multiple functions in one device, saving you from carrying several instruments. With field-optimized interfaces and robust data management, they reduce both time and errors.

• For many applications needing both precise measurements and field > mobility, solutions like the FieldFox offer an effective balance > that delivers results in any environment.

As measurement technologies continue to advance, do you think the distinction between field and laboratory equipment will eventually disappear altogether?

Reference

Correlating Microwave Measurements between Handheld and Benchtop Analyzers, Test World Inc.

Network Analyzer vs Spectrum Analyzer: What\'s the Difference in Use & Specifications, Keysight Technologies

RF Explorer Pro - Touch Screen Spectrum Analyzer, Core Electronics

Field vs. Laboratory Pressure Calibration: How to Decide, Transcat

N9918B Keysight Technologies Prices & Inventory - RF Test Equipment, oemsecrets

Selecting a handheld RF analyzer for tough conditions, AspenCore