Metal (Technical) Water (Personal)

MTN, Vodacom and Cell C square up against a Faraday Cage

Hold the Nobel Prize for Science.

Visting friends last night, they excitedly told me that they had a Faraday Cage. U had put her phone in the cage and tested it by trying to ring it (it connected outside the cage), but couldn’t get a signal.

Wanting to see this wonder in action, I put my cellphone in. They dialled it. It rang.

Hmm, a mystery, but nothing we couldn’t collectively solve.

First, we noted that my phone had a metal cage and and no external aerial. Guessing that the metal touching the exterior nullified the effect, we tried wrapping it in a thin cloth so that it didn’t make contact. It didn’t ring. We tested C’s phone, similar to mine, and it also rang when unwrapped. We wrapped it, and tried again.

It rang.

Another mystery. We tried various incarnations of wrapping with my phone – only the top touching, etc. It rang every time. Confused, we repeated the original wrapping experiment, leaving no surfaces touching.

It rang.

More inconsistency. Perhaps the fact that the Faraday Cage was a rusty old Absolut Vodka container meant it wasn’t operating at optimum efficiency?

The Faraday cage is the tall metallic thing, not the furry thing attached to C’s foot. Note also the subtle product placement. Unfortunately Apple’s product placement department haven’t returned my calls.

Perhaps the fact that U’s phone was an older generation, meant it wasn’t as powerful, and couldn’t decipher the weakened signal coming through the cage?

But then we realised another correlation. U’s phone, which couldn’t connect, was on the MTN network, and mine and C’s, which both did, were both Vodacom. (Mine’s actually a Vodacom number that was ported to Cell C, but let’s not confuse things). So we swapped sims, and put my phone in, uncovered, with the MTN simcard.

It didn’t connect.

We tried again with C’s phone and the MTN simcard.

It didn’t connect.

One last test to confirm the theory – U’s phone with the Vodacom simcard.

It rang.

Quite what we make of this conclusion I don’t know. The Vodacom tower is closer to the house than the MTN tower? MTN signals have a different wavelength and penetrate the cage less easily?

With further research I’ve determined that both Vodacom and MTN use GSM-900 (at least according to this and this). Now, anyone have an idea where the closest Vodacom, Cell C and MTN towers are to Barton Street, Woodstock?

We’ll credit you in our (Ig?) Nobel Prize.

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