DIY Faraday cage for a mobile phone

[Rob Morley]

Get a large cardboard box (or old wardrobe), wrap it in kitchen foil and sit inside it. :-)

[jrwalliker]

You'll need to make very good joins betweeen the sheets of foil to make that work.

Copper tape with conductive adhesive is ideal for this, but you had better be sitting down when you look up the price.

Bringing a cable into an enclosure is the best way to bring in mobile phone signals as well. When I needed to do almost exactly what you are doing in a commercial test chamber I had to filter every signal separately with feedthrough capacitors.

The chamber was quite impressive. They tested military vehicles in there - even tanks - and could rotate them on a huge turntable.

John

[The Natural Philosopher]

Try placing the phone inside some chicken wire or rabbit wire...not sure what the attenuation would be, but pretty high.

[The Natural Philosopher]

Right. Another thing to try is metal building lath.

This is used as a base for rendering. Its a deal smaller bore than chicken or rabbit wire.

And its dirt cheap.

[Chris Hodges]

I did some work with GSM signals, our faraday cage used mesh with ~6mm dimaond perforations.

[Darren Griffin - PocketGPSWorl]

Why not control the PPC remotely using software such as SOTi Remote Controller? Then you could szeal the PPC in the biscuit tin and have only a single cable to the PC?

[Rob]

Why not open the phone up and remove the antenna. Loads of attenuation can be achieved by that method

[tony sayer]

In article , Rob writes

And possible PA damage!...

[Skier]

I would use the tin idea with a small hole cut and connect the USB cable and then use "active sync remote display" to control and view the screen. Easy!

Then you can chop the tin up and creat some leaks to simulate different GPRS strength.

Paul

[Andy Wade]

Same could apply operating it in a biscuit tin, unless you introduce some RF absorbent lining.

So how about a dummy load connected via a length of coax into the outer of which you cut some slots, leaky-feeder style?

[Simon]

intermittent

Thanks for all the replies. I think I will seek out some finer mesh and try the cage route again. The cage built out of 12mm mesh does decrease the reading on the signal-strength icon, so I think smaller mesh may do the trick. I tried some other things, with limited success:

- I have tried disconnecting the internal antenna, but the connector is a tiny coax connector about 2mm in diameter, which will almost certainly break after a few repetitions.

- I don't want to activesync to the device under test, as that has an effect on the network configuration of the device. In fact, the device stops using GPRS altogether and sends its network traffic over the activesync cable.

[Jon]

[e-mail] declared for all the world to hear...

Only if you allow it to. Open activesync and un-check the "passthru" mode.

[Linker3000]

Why not just download the Pocket PC remote viewing/control software from Microsoft and operate it in the tin from a locally connected PC?

[Jon]

[e-mail] declared for all the world to hear...

What software is this you speak of?

[Linker3000]

Remote Display Control for Pocket PC

[Simon]

Thanks for all the replies, I have put together a webpage at

describing the faraday I eventually built, based on biscuit tin and chicken wire technology. It does block GPRS signals.