boon's log 1307.04: Handphone-in-a-Box

What happens when some engineers have a little spare time in their hands? Well, they conduct experiments, of course.

Presenting Mythbusters@work*.

*not related to the original Mythbusters, as seen on TV.

Ever wondered why your cellphone does not work in the lift (elevator)?

Well, some of us carried out an experiment the other day, by simulating the cellphone in lift (elevator) scenario. Simple experiment, you can even do it at home (or in the office, depending). All you need is a working cellphone (we use one of the most versatile cellphone in town - The SonyEricsson k750i) with sufficient network coverage in that area and a Biscuit Can or Tin - in this case we used the square metal biscuit box (Jacob's).



(A) As a control we called the cellphone before starting the experiment - just to make sure that everything works fine. It rings. Good.

(B) Then we place the phone inside the Can and then cover it. Then we call it again. The network provider reported back "No Network Coverage". INTERESTING! just by placing the phone in the can has cut-off all network lines to the phone.

(C) then we open the lid and called again. This time it went through. The phone was ringing.

(D) and finally, we called the cellphone when it is outside the Can, and then with the cellphone still ringing, we moved it into the can. It was still ringing. Then we cap-ed the lid on the Can. It was still ringing, but after the 3rd or 4th ring, the line went dead - no network again. Voila!

So the "Myth" IS true - the metal walls of the container cuts off all network lines that is connected to the cellphone - just like in an elevator. But when we left the lid opened, we were able to connect to the phone. So the coverage within the elevator depends highly on the amount of area not covered by metal (i.e. the ventilation openings on top of the elevator).





boon out...