630 meters band
The 630 meter band is a medium-wave experimental allocation near 475 kHz, prized for steady nighttime propagation and low-noise weak-signal digital work.
Propagation & character
By day, ground wave dominates and range is mostly local; after dark the band opens for skywave contacts of hundreds to over a thousand miles. Low noise and stable paths make it a favorite for WSPR and FT8.
What 630 meters is used for
CW and weak-signal digital modes (WSPR, FT8, JT9). There is no phone operation.
Operating tips
- Like 2200 meters, antennas are short and heavily loaded — a good ground system matters far more than transmitter power.
- US operators must notify the UTC before transmitting and observe a 5 W EIRP limit (lower in some areas).
- Quiet winter nights with low static give the best DX.
Antennas for 630 meters
A half-wave dipole for 630 meters is about 984 ft (300 m) end to end — impractically long at this frequency, which is why these bands use shortened, loaded verticals and loops instead of full dipoles. Work out an exact starting length with the antenna calculator, then trim for lowest SWR.
630 meters band FAQ
What frequencies is the 630 meters band?
The 630 meters band covers 472–479 kHz — part of the medium frequency (MF) spectrum. Common modes are CW, WSPR, FT8/JT9.
What is the 630 meters band used for?
CW and weak-signal digital modes (WSPR, FT8, JT9). There is no phone operation.
What license do you need to use 630 meters?
All US classes after a one-time UTC notification; 5 W EIRP limit.
How long is a dipole for 630 meters?
A half-wave dipole for 630 meters is about 984 ft (300 m) end to end, with each leg half that — impractically long at this frequency, which is why these bands use shortened, loaded verticals and loops instead of full dipoles. Use the HamDaily antenna calculator for an exact starting length, then trim to resonance.