How to perform accurate field strength measurements on a TFN RMT handheld spectrum analyzer?

Field strength measurement is a key component in assessing signal coverage quality during field operations such as wireless network optimization, base station deployment, and interference troubleshooting. The TFN RMT series handheld spectrum analyzers, with their portability, real-time analysis capabilities, and professional measurement functions, are ideal tools for engineers performing field strength measurements. This article will detail the operating procedures and optimization techniques, taking into account device features.

1. Key Preparations Before Measurement

1.1. Device Inspection and Environmental Configuration

Power-on Warm-up: Ensure the device is fully charged and power it on. Allow it to warm up for 30 minutes according to the manual to ensure internal circuit stability and improve measurement benchmark accuracy.

Antenna Selection: Select a whip, log-periodic, or horn antenna based on the target frequency band (e.g., 800MHz LTE or 3.5GHz 5G NR), and securely connect it to the N-type/SMA RF connector.

Environmental Safety: Keep away from high-power transmitters (e.g., radar stations) and avoid human obstruction of the antenna. It is recommended to use a tripod to secure the device to minimize operator interference.

1.2. Basic Parameter Settings

• Center Frequency: Press the `FREQ` key on the panel to directly enter the target signal frequency (e.g., 2140MHz).

• Span Setting: Press the `SPAN` key to set it to 1.5 times the signal bandwidth (e.g., 30MHz when measuring a 20MHz 5G signal).

• Reference Level: Use the `AMP SCALE` button to adjust the signal peak so that it occupies two-thirds of the screen height to avoid signal overflow or undershoot.

• Safety Tip: The input signal power must not exceed +26dBm (maximum safe input level) to prevent damage to the device.

2. Field Strength Measurement Procedure

2.1. Select Measurement Mode

Enter the main menu and select "Channel Power" mode. This mode directly calculates the total power within the specified bandwidth and is the core function of field strength measurement.

2.2. Key Parameter Configuration

2.3. Performing Measurements and Readings

• Point the antenna toward the signal source and start a continuous scan (`Run/Cont`).

• The main display area shows the spectrum in real time, and the field strength value (in dBm) is directly displayed in the information bar (e.g., -65.3dBm).

• Use the `Marker` function to locate peaks, and `Datalog` to record data and spectrum screenshots.

3. Accuracy Optimization Techniques

3.1. Calibration and Compensation

  Regularly send the device and antenna to a TFN-authorized agency for calibration.

  If manually compensating the antenna factor, enter the compensation value in the Advanced Settings.

3.2. Environmental Interference Suppression

• Multiple Sampling: Take 3-5 measurements at key points and average them to reduce random errors.

• Time Gate: For intermittent signals, enable the `Time Gate` function to exclude periods of interference.

• Map Annotation: Enable the built-in GPS and combine field strength values to generate a coverage heat map.

3.3. RMT Device Performance Advantages

4. Safety Operating Procedures

• Radiation Protection: Avoid prolonged close contact with high-gain antennas. Pregnant women and pacemaker wearers require special protection.

• Grounding Requirements: A three-core power cord must be used and a reliable protective ground connection must be ensured to prevent electrostatic damage.

• Environmental Adaptability: The IP54 rating supports field operations, but extreme weather conditions such as heavy rain and sandstorms must be avoided.

5. Typical Application Scenarios

• Base Station Coverage Verification: Mobile measurements along a predetermined path are combined with GPS to generate LTE/5G signal strength distribution maps.

• Indoor Distribution Optimization: Use an omnidirectional antenna to scan inside buildings and identify areas of weak coverage.

• Interference Location: Use persistence images to capture intermittent interference sources.

> Engineer's Tip: If readings jump during measurement, check the antenna connections or enable the preamplifier (when the reference level is < -40dBm).

Summary

Mastering the field strength measurement process of the TFN RMT handheld spectrum analyzer—from device warm-up and parameter configuration to accurate readings—is a core skill for wireless engineers. Its portable design is suitable for a variety of operations, including towertops, indoors, and outdoors. Its wide frequency band and high sensitivity ensure data reliability. Regular calibration, standardized operation, and environmental optimization are the three pillars for reliable results. Whether deploying 5G networks or maintaining traditional base stations, the RMT series provides an efficient solution for your field strength assessment tasks.