SF401 Plus 27MHz 3000MHz Portable Radio Frequency Counter Meter with CTCCSS/DCS Decoder Overview A handheld frequency counter and decoder designed for field and bench use. The SF401 Plus measures radio frequencies across a wide band and decodes CTCCSS and DCS signaling to help technicians, radio operators, and installers verify performance and troubleshoot communications equipment quickly and reliably. Key benefits Wide frequency coverage: measures from 27 MHz up to 3000 MHz to support a broad range of radios, scanners, transmitters, and RF equipment. Tone decoding: builtin CTCCSS and DCS decoder identifies subaudible tones used for repeater access and selective squelch, reducing guesswork when diagnosing tonerelated issues. Portable and easy to use: compact, handheld format for onsite testing or bench work; designed for quick setup and fast readouts. Problem solving: helps find frequency offsets, confirm transmitter output, identify interference sources, and verify tone configurations before deployment. Improves workflow: enables faster troubleshooting and verification so repairs and adjustments spend less time in the and more time back in service. Functions and performance Frequency counting across 27 MHz to 3000 MHz with rapid detection for transmitters and signal sources within that range. CTCCSS/DCS decoding to reveal subaudible tone information sent by radios or repeaters. Clear, concise measurements suitable for field checks, installation verification, and routine maintenance tasks. Compatibility Compatible with most twoway radios, handheld transceivers, mobile radios, base stations, scanners, repeaters, and RF signal sources operating within 27 MHz to 3000 MHz. Useful for amateur radio operators, commercial radio technicians, event communications teams, and maintenance personnel who need a portable frequency verification tool. Practical applications Field commissioning: verify frequency and tone settings when installing or configuring mobile radios at a vehicle or job site. Troubleshooting: identify whether interference or frequency drift is affecting a repeater or handheld radio and confirm whether tone signaling is correct. Preevent checks: confirm that multiple radios are transmitting on the correct frequency and using the correct CTCCSS or DCS tones before an event or deployment. Why choose this unit Broad coverage and tone decoding in a single handheld instrument reduces the need for multiple tools. Portable design and straightforward operation make it suitable for both experienced technicians and users who need a reliable verification tool in the field. Focused feature set supports common radio maintenance, installation, and troubleshooting tasks without unnecessary complexity. Specifications summary Model: SF401 Plus Frequency range: 27 MHz to 3000 MHz Function: frequency counter and CTCCSS/DCS decoder Form factor: portable handheld meter This SF401 Plus unit provides a practical, singletool solution for measuring radio frequency and decoding common signaling tones during installation, diagnostics, and routine maintenance.