The Joys of Comcast Pt.2

In the Joys of Comcast part 1, I shared my story of how Comcast has opened up what could be the biggest security hole since heartbleed, at least as far as the average consumer is listed. They have mandated a unencrypted wifi network be broadcast from every router in their customer network. They offer no way to turn this network off, and will even flat out refuse to when asked to. I've since set up my own WiFi network on separate devices, and now seek to end this xfinitywifi network for good.

The idea is to build a faraday cage, which is a device used to isolate electromagnetic fields and insulate them from the outside world. A realatively simple device, the faraday cage is a cage or box made of a conductive material. Through the magic of physics, this creates a force field of sorts for electromagnetic radiation(aka WiFi).

I set out to build one, heres the how to so you can do it to!

First you will need to take some measurements of your router. You will need at least the size of the surface area(plus a bit of overlap) of the router in conductive mesh. This is something between chicken wire and large screen.... realistically the smaller the holes the better (as you will see ahead).

You will need something to ground the entire cage with. I used an electrostatic bracelet for working on computers. you can use a piece of wire and connectors, or whatever you want.

NOTE: THIS GROUND WIRE WILL BE PLUGGED INTO THE WALL. YOU ONLY PLUG THIS WIRE INTO THE ROUND HOLE ON THE BOTTOM (US 120V). IF YOU DO NOT KNOW HOW TO USE A MULTIMETER AND CHECK THAT THIS IS PROPERLY GROUNDED, DO NOT GO ANY FURTHER, DO NOT ATTEMPT TO DO THIS MOD. I TAKE NO RESPONSIBILITY FOR ANY INJURY OR DAMAGES THAT COME FROM FOLLOWING THIS POST. PROCEED AT YOUR OWN RISK. THIS CAN BE DANGEROUS

You will need some tape... I used gaffer tape, but it wasn't a great choice. Duct tape, packing tape, or electrical tape will all probably work better. The tape ended up being more to protect the aluminum foil.

You will also need some aluminum foil. A few feet should do, but more probably wont hurt.

At this point, its pretty much up to you and your creativity. Wrap the Gateway completely in aluminum foil, then in your mesh cage, and finally make sure the mesh cage is grounded. There needs to be no holes anywhere in the enclosure, so get creative around the chords at the back. Heres some results:

This was my baseline reading. As you can see, the network xfinitywifi has the same strength as HouseLANister, which is my home network. This was with no modification.

 Then I added the mesh cage, and grounded it. While there was a definite drop in signal strength, it was not enough to make me happy.

Enter aluminum foil: Again, a signal drop, but not quite enough.

So what do we do? Combine them of course. 

 And finally, a screenshot from the mailbox.... While the network is still there, its got significantly less signal strength. I think I'll likely redo this again, but with finer mesh, and instead of wrapping the router, I think I'll build a box and set it inside. This shows some potential as a proof of concept, but definitely needs refinement in order to work 100%.