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This answer to What is this propellor-like object on top of the SpaceX Hopper? includes the following:

FCC filing: Space Exploration Technologies Corp. 0459-EX-CN-2020:

...d) List any natural formations of existing man-made structures (hills, trees, water tanks, towers, etc.) which, in the opinion of the applicant, would tend to shield the antenna from aircraft:

This radar will be attached to the top of a water tower and is masked between 164 to 290 degrees to avoid illuminating launch or test vehicles. Please note that a TFR will be in place when the radar is operating.

Question: What exactly does "TFR" stand for in this context? How does one put one in place when a radar is operating?

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It stands for Temporary Flight Restriction.

Source: https://en.wikipedia.org/wiki/Temporary_flight_restriction

Presumably the TFR is in place for whatever SpaceX is doing and the radar will be utilized during that same event. So the two things are associated, but one is not because of the other.

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    $\begingroup$ Airplanes have no knowledge of and won't be disrupted by marine radars, they use different frequencies. $\endgroup$ – GdD Jun 12 at 9:41
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    $\begingroup$ Generally not @uhoh, marine radars are design to look towards the horizon and to filter out fast moving objects, so it may see a helicopter hovering over the water but wouldn't see airplanes. $\endgroup$ – GdD Jun 12 at 12:48
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    $\begingroup$ @uhoh, it would have to be low to the surface to be seen as marine radars send out a narrow beam, I'm sure there are models which are configurable that way, or if you're SpaceX you'd just hack it. $\endgroup$ – GdD Jun 12 at 13:34
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    $\begingroup$ Maybe this is too obvious, but perhaps they just wanted to look for boats before starting a test? One of my friends who is vacationing down there just posted some pix of Boca Chica from a boat. $\endgroup$ – Organic Marble Jun 12 at 13:40
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    $\begingroup$ I'm sure your local aviation authority would be happy about that @uhoh. They like that type of initiative... $\endgroup$ – GdD Jun 12 at 13:44
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A TFR is a Temporary Flight Restriction. My best guess for why SpaceX would include this information in their filing is that the FCC requires that marine radar does not interfere with airplane operations, and what SpaceX is saying is that because of the fact that there are no airplane operations when the radar is transmitting, there is no further need to demonstrate its safety.

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  • $\begingroup$ If it's a standard commercial marine radar, then people use it all the time when airplanes are flying, is it the height that's different? Or has it been modified? Otherwise why mention this? $\endgroup$ – uhoh Jun 12 at 23:02

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