[Discuss-gnuradio] Need help identifying jammer signal

Hi,

In the last few days a signal has entered in the center of our incoherent scatter radar band. It drifts between 440.1 and 440.4 MHz very slowly and has approximately a 10 kHz bandwidth. A scope plot of the signal shows something that looks a little bit like frequency shift keying. While the frequency is stable on short time scales, the signal tends to drift a lot on the scale of days, suggesting that whatever is causing this signal, it is broken.

I've attached a GRC plot of the signal. In the plot, the jammer is at a +166 kHz offset. The scope plot is centered at this frequency and has a 40 kHz bandwidth.

Does anyone have any idea what this could be?

juha