16 February 2018

OFDM 30-tones PSK-2 40Bd


Yet another unid (to me) OFDM transmission spotted by ANgazu on 4 MHz band by using a remote Kiwi SDR in Sweden (SM2BYC).
The waveform uses OFDM technology for 30 channels, 50 Hz spaced, modulation is PSK-2 in each channel with a symbol rate of 40Bd. The occupied bandwidth is about 1500 Hz. Speed and modulation are confirmed by analyzing the whole signal and also a single channel (Figs 1,2). A short preamble consisting of FSK-2 40Bd/320 bursts precedes the OFDM (Fig. 3).
The same signal was spotted by KarapuZ on may 2015, here his post in radioscanner:

Fig. 1
Fig. 2
Fig. 3