Short Rules for FMT Participation
These are simplified, beginner-friendly rules explaining how FMT tours work. No formulas, no advanced theory — only the essentials.
Who can participate?
- Any radio amateur with basic HF or SDR equipment
- You don’t need a frequency standard or special lab gear
- Both beginners and experts compete in separate classes
What is the goal?
The goal is to measure the frequency and timing of the FMT beacon signal as accurately as your equipment allows. Your result is compared to the reference, and you receive a score.
- HF skywave propagation can shift the received carrier frequency (Doppler and frequency shift).
- Calibrations and reference equipment help reduce systematic offsets, but they do not make the HF channel laboratory-grade.
- Scoring is comparative; the aim is to compare measurements against the reference, not to establish the transmitter's absolute "true" frequency.
How tours work
- Each tour has a published UTC time window
- Tune to the announced FMT frequency
- Record the signal or observe it in real time
- After the end of the tour, analyze your recording
- Submit measured values on the website
- What is transmitted and when: FMT Tour Transmission Format
What you need to submit
- Your measured carrier frequency (FREQ) — a reference carrier on the published calibration frequency is transmitted before the measurement cycles
- Pulse duration (PULSE): measure the duration of the 3rd pulse in a packet of three 1 kHz sinusoidal pulses (1st = 100 ms, pause 100 ms; 2nd = 50 ms, pause 100 ms; 3rd = tour-specific duration, the same for the whole tour)
- 1PPS offset (PPS): the time from the start of the 1PPS second to the start of the first pulse of the packet (50% envelope level), the same for the whole tour
- Optional notes about your equipment
Note: Submissions can be corrected before the tour closes.
Classes (PRO and Hobby)
Hobby class
Regular HF or SDR setups. Scored in FREQ and PULSE; PPS can be submitted for information and self-checking but is not scored. Beginners start here.
PRO class
Overall PRO standings and all metrics, including PPS. Usually GPSDO-based or laboratory-grade setups, but a GPSDO is not required.
Scoring (simple explanation)
Your score is based on how close your measurements are to the reference values. Smaller errors give more points. Detailed mathematical scoring is described in the full Rules page.