Decode e-Czas (225 kHz, Poland) with an SDR

Group

Weather & science

In the mode list

LW time service, Poland

What e-Czas (225 kHz, Poland) is

E-Czas, the Polish national time service (GUM) on the 225 kHz long-wave carrier of Polish Radio 1: 50 bit/s phase keying, time packets with the date, the local offset, the summer-time and leap-second flags and the transmitter state, and how far the computer clock is off. Needs a radio that tunes to 225 kHz (or an upconverter).

Frequencies and settings

OnAir takes any frequency you type; the numbers above are the mode's starting point and the range its table describes. In the app the shortcut label is LW time service, Poland.

What OnAir shows

e-Czas, the Polish national time service (GUM) on the 225 kHz long-wave carrier of Polish Radio 1: 50 bit/s phase keying, time packets with the date, the local offset, the summer-time and leap-second flags and the transmitter state, and how far the computer clock is off. Needs a radio that tunes to 225 kHz (or an upconverter).

Limits and what it was checked with

Checked with generated signals and impairments; recordings of real signals welcome.

Which radio you need

This is a shortwave mode, so the radio has to tune HF. An SDRplay, Airspy HF+ or an RTL-SDR in direct-sampling mode do that directly; with a HackRF an HF upconverter or a direct-sampling receiver is the usual route. A long wire or loop antenna matters more than the radio.

Receiving and the law

Questions about e-Czas (225 kHz, Poland)

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