Sorry US; Europeans Listen To Space With GRAVES

In Europe, the GRAVES radar station beams a signal on 143.050 MHz almost straight up to detect and track satellites and space junk. That means you will generally not hear any signal from the station. However, [DK8OK] shows how you can–if you are in Europe–listen for reflections from the powerful radar. The reflections can come from airplanes, meteors, or spacecraft. You can see a video from [way1888] showing the result of the recent Perseid meteor shower.

Using a software-defined radio receiver, [DK8OK] tunes slightly off frequency and waits for reflections to appear in the waterfall. In addition to observing the signal, it is possible to process the audio to create more details.

Why is there a giant vertical radar transmitter in the middle of France? The transmitter uses a phased array to send a signal over a 45-degree swath of the sky at a time. It makes six total steps every 19.2 seconds. A receiver several hundred miles away listens for reflections.

Even the moon reflects the signal when it is in the radar’s path. If you are interested in a moon bounce, you may be able to build a station to hear the reflections without being in Europe.

Of course, if you can transmit yourself, you might want to bounce your own signal off airplanes. If you want to do it old school, you could emulate [Zoltán Bay].

18 thoughts on “Sorry US; Europeans Listen To Space With GRAVES

  1. “Why is there a giant vertical radar transmitter in the middle of France? The transmitter uses a phased array to send a signal over a 45-degree swath of the sky at a time….”

    That answers the “how”, not the “why.” So why IS it there…?

    Oh. Top of the page: “to detect space junk.” I guess I would have phrased the “why” question as, “So why locate it in the middle of France?” Nitpick now over.

    1. A number of years ago I came across a web page by a ham in Florida who built a system to detect satellites using the Air Force system transmissions. He used 220 MHz ham radio equipment tuned down to the transmission frequencies.

      He was pretty far from the transmitters and had a small antenna system so he could only detect large satellites at high altitudes. Eventually he wrote software on his Apple computer to calculate their orbits. He refined it by comparing his results to published orbital elements for known satellites.

      Eventually he caught the attention of the government and was “invited” to Washington DC to describe his system to the CIA. After telling them what he did, they thanked him and said they expected someone would eventually do something like that, and they wanted to see if he did what they expected or came up with something new.

      It was really a good read. I tried to find the site again but no luck. Maybe he took it down.

        1. It did start a train of thought though, the way to detect subs is by SONAR or by listening to sounds coming from it or looking for their magnetic disturbance signature.
          And that last one made me wonder if you could detect that from space with sufficiently sensitive equipment, since a large metal tube disturbs the magnetic field of earth and that in turn might cause an ever so tiny ripple in the ionosphere, so I wonder..

          1. Oh additionally you could also detect them by heat and the bubbles created by the screw I suppose, or by a interrupter maybe? Light-based or a magnetic field one.

  2. Interesting. I have always wonder would I could do radar wise with my amateur radio privileges. Time to dig out mt old packet equipment, and send some beacons over head so see if I get any reflections. I live in Kansas fly over country. Some nights the noise from jets is so great, I have to wonder if WW III has commenced.

      1. Whatever… Prior to the detonation of said war heads we will hear the incoming and outgoing vehicles delivering the war heads. Of course my point was illustrate, in some manner how loud the heavens can be, some nights at my location.

        1. Incoming missiles are ballistic so they won’t have a engine by the time they are near the target to hear since they use inertia.
          Also since they come in at 5+ times the speed of sound they land before any sound that might come from the re-entry vehicle.

          They already use to say it in the old WW’s how ‘you won’t hear the shell that kills you’ since the sound you hear means it passed over you already, and that were conventional weapons.

  3. Would you not need two or more receivers some distance apart to get some more data? I mean to get the position and such. Plus you’d be helped by some sort of synchronization to the transmitter I imagine. or what? Although if the transmitter is so regular I guess you only need to have a time code for its sweeps and you can calculate the sync from the multiple of 19.5 secs..

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