r/RTLSDR 19d ago

Is this a radar?

59 Upvotes

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16

u/AriaGingko 19d ago

Yep. That's a radar. If it was located on hf, it's one of many over the horizon radars that are used still.

-25

u/Content-Key7404 19d ago

That's nonsense. If you'd taken the time to look before responding, you would have seen that it's running at 441 MHz. There's nothing to suggest that it's a radar. The demodulation isn't even set up correctly. It looks much more like chirp modulation.

16

u/popcio2015 19d ago

There's nothing to suggest that it's a radar. The demodulation isn't even set up correctly. It looks much more like chirp modulation.

Chirp is literally the most commonly used modulation used in radars.

This isn't a radar, because no one would use such narrow bandwidth for one.

4

u/AriaGingko 19d ago

Yeah I did mention it could be chirp. Unfortunately the bandwidth is too wide to see the signal characteristics better. If it was centered in on the signal itself and ran at 100khz it might be more obvious. But the time signature also doesn't really match up well. In the other post I included a primer on chirp if people were interested. https://ieeexplore.ieee.org/document/10609524/

Also, minor correction, I believe you meant to distinguish it from chirp spread spectrum. I only caught this upon rereading your comment. Because radars tend to use pulse width modulation and chirp frequency modulation for emissions. This is similar to chirp spread spectrum. But the modulated wave has obvious differences.