7500 kHz
A number of similar HF radar signals have recently been observed on KiwiSDRs located in Europe on different frequencies.
The pulse repetition rate is 40 Hz (25 ms/pulse).
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| abs(IQ) |
Each pulse consists of a linear chirp and of a pause.
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| FM demodulation |
KiwiSDR TDoA multilateration indicates that these signals come from somewhere in Russia.
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| KiwiSDR TDoA multilateration |
Bursts of what seem to be linear FM chirps have been observed on different frequencies around 8050±~50 kHz.
6390 kHz
Like the signal on 7500 kHz the pulse repetition rate is 40 Hz. However the duty cycle is smaller.
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| abs(IQ) |
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| FM demodulation |
8050 kHz
For this signal, the pulse repetition rate is 96 Hz.
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| abs(IQ) |
Each pulse consists likely of a linear chirp. The spikes in the instantaneous frequency seen below are probably cause by HF propagation effects. Note that these radar-like signals are narrow-band (±1kHz variation in instantaneous frequency, only)
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| FM demodulation |
KiwiSDR TDoA multilateration indicates a position somewhere in the Atlantic Ocean (compatible with the Azores).
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| KiwiSDR TDoA multilateration |
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