Tips:

This product is an entry-level device for routine troubleshooting, not a high-precision instrument. Its main advantage is that it integrates field strength measurement functionality within a very portable and compact body.Field strength testers and frequency testers are two different categories. This product does not have a chip for measuring frequency. The device determines whether the transmitting equipment is faulty and whether the antenna is of good quality based on the electromagnetic strength coupled from the antenna.

Overview:

The -FSM is a professional handheld field strength meter. It is designed for radio enthusiasts, antenna tuning engineers, interference troubleshooting specialists, electromagnetic environment assessors, and any user wishing to visually observe electromagnetic fields. Compact and portable, the device offers a professional and intuitive experience for measuring field strength. Key features include: wide frequency band coverage, a broad measurement range, intelligent data logging capabilities, and extreme portability. This device supports a wide variety of application scenarios, offering enhanced versatility; it can be used to measure antenna reception signal strength, compare the reception performance of different antennas, test the radiation intensity of transmitters, verify the actual radiation characteristics of antennas, and measure the polarization direction of receiving antennas at various spatial positions and angles. 

Key Selling Points:

1. Wide Field Strength Measurement Range—Covering Both Strong and Weak Signals:

Features built-in hardware-level attenuation (20x) and gain (20x) switching. In attenuation mode, it supports input levels up to +49 dBm without signal saturation or distortion. In gain mode, it can detect signals as low as -115 dBm. It is capable of measuring milliwatt-level devices in the UHF/VHF bands, multi-watt transmitter systems, and complex electromagnetic environments in the HF band. This enables engineers to accurately measure field strength and assess signal coverage and transmission performance.

2. Frequency Range: 0.5 MHz to 5 GHz:

By simply swapping to the appropriate antenna, the device can measure field strength across a spectrum ranging from low-frequency magnetic fields to microwave bands. It can also be used to measure power-frequency magnetic fields surrounding household electrical outlets. Ideal for both professional measurement tasks and general electromagnetic exploration. (Note: The default accessory antenna is tuned to 433 MHz; for testing other frequencies, please provide your own antenna. Measurement results will be significantly more effective when using an antenna that resonates specifically with the frequency being tested.)

3. Graphical Interface with Four Display Modes:

Features a graphical menu system for intuitive operation. Includes four built-in display modes: Digital Mode (for precise numerical readings), Pointer Mode (for visualizing signal fluctuations), Graph Mode (for observing trends over time), and Logger Mode (for automatically recording the maximum field strength value detected during a measurement session). During outdoor testing, antenna tuning, or interference troubleshooting, the device allows users to lock onto instantaneous peak values, enabling them to quickly identify the optimal antenna orientation or the location with the strongest signal.

4. Full-Color HD Screen, Adaptable to Day/Night and Various Orientations: Equipped with a 1.8-inch full-color display (256×128 pixels). Supports both Day Mode (high brightness for outdoor visibility) and Night Mode (soft lighting). The screen orientation can be freely switched between landscape and portrait modes.

5. Compact and Portable with Built-in Long-Life Battery: Features a highly integrated design with a compact body that fits easily into a pocket. The built-in 800 mAh battery supports over half a day of continuous testing on a single charge. Ideal for mobile applications such as tower-top commissioning and on-site troubleshooting.

6. USB Type-C Port for Charging and Firmware Updates: Utilizes a standard USB Type-C port supporting 5V/1A charging, compatible with most mobile phone chargers and power banks. It also serves as the interface for firmware updates; simply connect the device to a computer—following the instructions in the user manual—to update the firmware without the need for a dedicated programmer.

Specifications:

- Model: -FSM (Two models are available for selection: Model A features a 3D-printed housing, while Model B features a CNC-machined metal housing; aside from the housing material, there are no other differences.)

- Frequency Range: 0.5 MHz to 5 GHz - Field Strength Measurement Range: +49 dBm to -115 dBm

- Range Switching: 20x Attenuation (Max: +49 dBm); 20x Gain (Min: -115 dBm)

- ADC: 16-bit High Resolution- MCU: ESP32 (240 MHz)

- Antenna Interface: SMA-KE

- Battery Capacity: 800 mAh

- Charging Port: USB Type-C 5V/1A (Fast chargers are not supported)

- Display: 1.8-inch High-Quality Full-Color Screen - System Language: English

- Dimensions: 6.4 cm x 4 cm x 1.6 cm

- Weight: Model A approx. 45 g; Model B approx. 63 g

Important Notes:

1. Receiving Antenna: Users must provide their own receiving antenna appropriate for the specific signal frequency being measured. Using an antenna that does not match the measurement frequency will result in a significant degradation of test performance. The antenna included with the device is designed exclusively for the 433 MHz frequency band; if you need to test other frequencies, please purchase the appropriate antenna separately, ensuring that the antenna connector is compatible with the device interface.

2. Measurement Distance: During measurement, it is imperative to maintain a minimum distance of 20 cm between the transmitter antenna and the -FSM unit. If the distance is too short, strong signals may damage-or even burn out-the internal components of the -FSM, or prevent the device from functioning properly.

3. Measurement Range Settings: Before commencing measurements, you must first set the device to an attenuated range setting to prevent instantaneous signal spikes from damaging the -FSM. During the measurement process, the input signal strength must not exceed the -FSM's maximum safe operating voltage of 3.0 V; the absolute maximum withstand voltage is 3.3 V.

4. Charging Method: Fast-charging adapters are not supported; please use a standard, slow-charging power adapter.

Package Contents:

1 * -FSM Main Unit

1 * 433 MHz Antenna

1 * SMA-JJ Adapter (Provided to facilitate the connection of antennas with different interface types.)

1 * USB Type-C Data Cable

1 * User Manual