Frequency Counter Meter SF401 Plus 27MHz-3000MHz - Portable Field Tool

Our review of the SF401 Plus finds it best suited to radio hobbyists and field technicians who need a compact, portable way to confirm transmission frequency on two-way radios. The bottom line: this handheld frequency counter reliably measures continuous carrier signals from 27MHz to 3000MHz and provides a simple signal strength indicator, so users can quickly verify where a radio is transmitting without bulky gear. It is not designed for wideband or complex modulation analysis, but for its stated purpose the small size, four-button interface and included antennas make it a practical, value-oriented instrument.

Key Features

• Wide frequency coverage: Measures continuous carrier transmissions from 27MHz to 3000MHz so it covers most two-way radio bands hobbyists and technicians use.
• Signal strength indicator: Built-in strength reading helps confirm reception quality while you verify the transmission frequency in the field.
• Portable design: Small footprint and four-button control make it easy to carry and operate during outdoor checks or quick service calls.
• Included accessories: Ships with VU 144/430MHz and UHF 400-470MHz antennas, AC adapter, USB cable and manual so you can start measuring right away.
• Temperature compensated accuracy: Uses a TCXO for stability, maintaining roughly +/-2 to +/-4ppm accuracy across -45 C to 65 C for consistent readings in varied conditions.
• Range selection: Multiple easy ranges are provided to simplify tuning to the frequency band you need to inspect.

Who It's For

The SF401 Plus is ideal for amateur radio operators, repeater maintainers, and two-way radio installers who need a quick, portable check of transmission frequency and relative signal strength in the field. Its compact size and included antennas make it convenient for on-site troubleshooting and verification without a full bench setup.

It is not the right choice for users who require wideband analysis, demodulation, or precision lab-grade measurement of complex signals; those professionals should look to larger test instruments intended for broadband or modulation analysis.

Pros & Cons

Pros

• Compact and portable form factor that is easy to carry to field sites.
• Good range coverage for most two-way radio bands from 27MHz to 3000MHz.
• Includes antennas, power adapter and USB cable so it is ready to use out of the box.
• Temperature compensated oscillator provides stable accuracy across typical outdoor temperatures.

Cons

• Functionality and accuracy were described as mixed by some users, so results can vary depending on signal conditions and expectations.
• Not suitable for wideband signals or in-depth modulation analysis; strictly for continuous carrier frequency counts.

Specifications

Product type	Portable frequency counter meter
Frequency range	27MHz to 3000MHz
Signal type	Continuous wave (two-way radio carrier)
Included antennas	VU 144/430MHz and UHF 400-470MHz
Power and cable	AC power adapter and 11.8in USB cable
Stability	TCXO; approx +/-2 to +/-4ppm between -45 C and 65 C

Our Verdict

The SF401 Plus is a practical, budget-friendly tool for anyone who needs to confirm transmission frequency and signal strength of two-way radios on the go. It offers broad band coverage, useful included accessories, and stable TCXO timing, making it a good value for field use; users who need wideband or precision lab analysis should choose a more advanced instrument.

Frequently Asked Questions

Can this unit measure wideband or complex modulation?
Answer. No, the SF401 Plus is designed to count continuous carrier signals and is not suitable for wideband or modulation analysis.

What frequency range does it cover?
Answer. It measures transmission frequency from 27MHz up to 3000MHz, covering most two-way radio bands.

Does it include antennas and cables to start testing immediately?
Answer. Yes, it ships with VU 144/430MHz and UHF 400-470MHz antennas, an AC adapter, an 11.8in USB cable and a user manual.