Can anyone tell me what is the range in miles of the radar on a 747?

Sayid salvaged the radar unit from the Beech18 wreckage John and Boone found on the island that crashed years before their plane crashed, not the 747.

The 747 radar has a range setting of 640nm but getting all the various components and the wiring out of a crashed 747 and hooked up would impossible. Also the weather radar antenna is behind the radome which is probably the first things to get damaged in a crash.

The question about the Lost forum would be "What is the range of a radar installed in a Beechcraft 18?" They used the plane to transport drugs, so the radar was probably added on.

Range was limited to 25 miles because it was on a boat on the ocean. Anything past that and the curvature of the Earth gets in the way.

Good news for you. One of the radar options in the B747 is the MultiScan™ Weather Radar, which has a maximum turbulence detection range of 320nm (593 km or 370 miles).

It is practically impossible and exceptionally hazardous to use it in a raft, and the range will me much lower. I am not familiar with the "Lost" series, so dont know its intricacies. However, I've worked a bit with weather radars, so I would say that all it can detect is weather and cannot be used to detect point targets (like a boat, or maybe even land). Placing it on a raft will bring down its practical range to 5 or 6 miles.

That asides,when it is airborne, you are right in your argument with a luxurious margin.

And I would like to mention to the other answerers that the maximum range need not always be altitude dependent. When sitting on the runway, pointing it 15° above horizon would take care of the earth's curvature and enable it to detect turbulence at maximum range.

Well, there's many different types of airborne radars: Weather avoidance, ground mapping, and intercept to name three. The radar on all commercial (and military for that matter) variants of the 747, is simply a weather radar. MAX range IIRC is about 120nm, typically though it's used at 60-80 nm.

It depends on the altitude of the aircraft, the higher it is the further out it will work. The radar was meant to work in an aircraft cruising along at 33,000 feet not on a raft, it wouldn't be feasible to mount and successfully work.

I am not sure but I would think that placing a powerful radar like that on a raft would expose you to some heavy radiation- proceed at your own risk.

It depends, generally however it is only useful out to about 160 miles or so from a cruizing level due to the curvature of the earth.

We normally use it out to about 80 miles or so.