OTish - can you pick up a planes radar on the ground ?

Yes, heavys do.

Not enough to matter.

No, different frequencies.

some. Not many

microwatts. No.

What are you actually wanting to achieve? Commercial planes are constantly broadcasting their ID, position, speed, altitude, etc. - and this info is used by the likes of FlightRadar24 to show what aircraft are in the sky, and where they're going. You can pick up *this* data with a suitable receiver, or you can see it indirectly by using the FlightRadar24 app on a mobile phone. You're supposed to be able to point your phone at a plane, and the app will tell you what it is and where it is going - but I've never managed to make that bit work.

Forward for weather avoidance, downward for the radio altimeter.

Not a lot, but more than adequate for almost any receiver on the right frequency to detect.

And could a mobile phone pick it up ?

No, wrong frequency.

Lots of good answers already but I'm interested in what's behind the question. Many, many years ago I worked on the Concorde Weather Radar development and designed and built some of the equipment used to test it

- not bad for a sixteen-year-old schoolboy on a summer holiday job, eh? The golden rule in the lab was to keep well out of the way when the radar was powered up because the microwaves would boil your gonads in a second. But under ideal conditions there's an inverse square law in force here and because you hardly ever operate under ideal conditions in practice what you are going to get on the ground from an aircraft in the air will be far lower even than calculated.

If you are concerned about health effects under the flightpath or whatever I wouldn't worry about it. The signal strength would be less than that radiating from your mobile when you talk - or if you don't carry one because of concerns about health, less even than that chap over the road talking into his.

But if you are on the tarmac at the airport, don't stand in front of the waveguide!

Nick

If we are talking commercial rather than military, then they may have weather detection radar, and probably a radar altimeter, but they don't necessarily have what most people would think of as a general purpose radar.

Larger craft may have Traffic Collision Avoidance Systems which can use multiple sources of information (typically from positional transponders on other aircraft) to detect and plot what is around them (and also give advice on avoidance, or in some cases, actually take avoiding action automatically).

Small craft may use the Traffic Information System. This uses the ground based ATC radar to broadcast positional information back to the aircraft (via a signal modulated on their radar illumination). However again this is not an active broadcasting radar.

With the right receiving equipment, you may be able to detect the presence of some types of commercial radar (if you think about it logically, if they are broadcasting enough signal to monitor the bounce, then there must be more than enough to detect at ground level).

However a phone will not cover the right areas of spectrum without additional hardware.

For military stuff (where they may have proper down looking radar - especially on ground attack and recon aircraft)), then in theory some might be detectable, but much of the good stuff will be frequency agile and spread spectrum, so chances are you may not even be able to detect their broadcast.

Sheer curiosity - nothing more :) Provoked by idly seeing two largish passenger airliners passing overhead, and wondering if they project a radar front that could be detected by anyone with the appropriate equipment. As I said, googling "can you detect a planes radar on the ground using a mobile phone" simply reduced the last 5 years of "AI" hype to dust. If that's the level we're at, I don't want it looking for terrorists, or trying to diagnose disease. (The assumption that google made was that I wanted to "use a mobile phone to track planes" at which point most results were direct and indirect links to flightradar24. Which I already know very well.)

Flight Radar app on iPhone will tell you what is in the air around you and where its going to and from.

Mike

Which is what Google bolloxed up - despite the question being obvious.

I really couldn't give a s*it what's up there. Just wondered whether any radar waves could be detected on the ground.

Of course they must be with radar altimeters which all heavies have.

Peter Parry a exprimé avec précision :

Well the planes that sparked the question were within approach of Birmingham airport ? No more than 1km high ...

As others have said, the radar in non-mil aircraft is for weather avoidance but it can be tilted downwards and used to map (for example) coastlines.