(OT) Will a cellphone work under water?

[hrhofmann]

Not very far

[Tony Hwang]

Hi, If I were you, I'd experiment myself. Put the phone in a plastic bag ,aking it water tight. I can still punch the keys and ty it to see if the signal gets out.

[Tony Hwang]

Hi, If I were you, I'd experiment myself. Put the phone in a plastic bag making it water tight. I can still punch the keys and try it to see if the signal gets out.

[mikelucas3]

Assuming a cellphone could be made to be water resistant, would they get a signal under water? Obviously, no one can talk under water, so texting would be the only option.

But I doubt that there is such a thing as a waterproof cellphone made anyhow. My only reason to ask this is because I'm curious if a cellphone signal will penetrate water.

Anyone know?

[Ralph Mowery]

At the frequencies the phones work, they will not work under water. Maybe a few inches at the very most if you are next to the cell tower.

Don't ask me to explain this.But at the bottom is a number for 1 mhz of only .25 meters. That is less than a foot and the higher in frequency,the less the radio waves will penetrate.

[harry]

I had a radio controlled model submarine once. That worked underwater. Tx was above obviously and the distance was only about thirty feet. I don't suppose it went more than a couple of feet below the surface. It had a timed surfacing device in case things went wrong. Which they sometimes did.

[Kurt Ullman]

All you would really need to do is to look at the signal strength at various levels.

[Felix]

Harry,

A turd in the bath tub, is not a submarine in the water.

[Robert Macy]

There are charts that supply the information for the amount of absorption vs frequency in sea water. For the cellphone the field is very spherical and will 'punch' through salt water much better than the tower's rather planar field which will more follow the predictions of skin depth, etc.

However, for fun, let's use your experience with the submarine. Assume you had a 100mW 27MHz transmitter that went about thirty feet in water.

Adjust for power and frequency: Assume power scales, so 1W goes 10X further. Assume skin effect kills your signal, so at 900Mhz your signal will be reduced by the sqrt(900/27), or about 1/6th

Therefore the cellphone should work to an adjacent tower about 30*10/6 or 50 feet into water.

That is far deeper than I would expect, wonder what it really is.

[hrhofmann]

:

Try your phone in a bag in a barrel of water

[Robert Macy]

If that's rain water, unlikely to have much noticeable attenuation at all.

Well/city water somewhat.

Sea water will attenuate the most.

Plus, don't have cell-phone service provider.