Physically Masking Your Wifi Network?

I have a high-speed cable internet connection, which I transmit throughout my place using an Apple Airport Extreme base station. This way my wife and I can work on our laptops (almost) anywhere, and both portables and our desktop Mac can share the same printer without swapping any cables. It’s wonderfully convenient, and plenty fast; being able to surf the net from bed or on my couch has me hooked on wireless. I’m never going back!

But I do get a little worried about security. Our wireless LAN is protected by encryption and password admission, per usual, but it’s still possible to “see” it from outside. We live in a condo unit with adjacent units, and I can see my neighbor’s wifi setup; he can see mine. Before he figured out how to make his wifi secure, I was even able to log onto his and use it (which I informed him of immediately). I think we’re all pretty trustworthy, but you never know I guess. Passwords and encryption aren’t 100% secure, or there wouldn’t be any point in hacking. Chances are we’re fine, but it would be nice to add an extra level of security.

One thing I’ve thought of is simply physically shielding one side of the Airport base station, so at least some amount of signal is blocked. I’m guessing the transmitter emits its signal in all directions, like a bare lightbulb would cast light in a spere around it, and if I covered one side of the “bulb”, there would be a shadow on the other side, the volume of which increases roughly as the cube of the distance x 1/3 (for a square shield, for instance). If the shielding were completely opaque, given my probably oversimplified example, that would make it difficult for anyone on one side of the building (outside of my unit) to get a good signal, as they would have to be way off to the front or the back of the unit to get out of the “shadow”, and by then they’d be far from the base (signal drops, I think, as roughly the square of the distance). According to the manual, metal objects can interfere with transmission, so I guess something metal would do.

We have some equipment at work that has to be shielded from EM interferance. Around this equipment is a “Faraday Cage”, which is nothing more than a rectangular booth about the size of a phone booth, sided with metal screen that doesn’t look much different than window screen. It really works! You should see the dials jump if you hang one of the probes outside of the cage.

So maybe just some metal screen would do the trick? Or do I need some sheet metal? Also, will either screen or some other form of shielding reflect? Ideally, the material I would use for shielding would absorb all the radio energy, but I don’t think such stuff is easy to come by. So, it would stand to reason that my shield probably would reflect, and it has occurred to me that this reflection might cause regions of interferance, where waves emitted directly from the base happen to be out-of-phase with waves reflecting off the shield, and hence cancel each other out (I guess there would also have to be regions of enhancement of signal, too, but what I’ve got is strong enough, thanks). I don’t want to create more nodes in my place where I can’t receive than I already have (a few do exist, I’ve found, and I suspect the duct work, which is wrapped in foil-backed insulation).

So A) Is there a good way to shield an Airport (which transmits in the 2.4 GHz band) from unwanted receivers? And B) Would such shielding cause me more headaches than the worry about security would make it worth?

Thanks for your help!

Loopy

You are on the right track but there are a few gotchas that will probably make it not worth the effort. A tinfoil hat will block high frequency radio waves wich are pretty much line of sight but as with light they can easily reflect in directions you don’t want. Try the experiment with a bare bulb in a lamp. Make an opaque cardboard shield and place it near the bulb. One side of the room got dimmer but it sure didn’t go completely dark. I’m not saying 2.4GHz will be as reflective but you see what you’re up against trying to make an ominidirectional antenna into a purely directional one.

My best idea:

The Cantenna!

Put it on the base station, and point it in the direction you only want the WiFi to go in. See if that helps.

The TechTV show The Screen Savers recently did a segment on a printable antenna which is claimed superior to the cantenna. The creator comments “Therefore you have more control of where your signal is going when using this reflector. That feature of this antenna can be used to enhance the privacy of your wireless network and that was my reason for designing it in the first place, the rest is just gravy. . .”

There should be a setting on your wireless router configuration something like “Enable SSID Broadcast.” Make sure this is disabled. This will prevent the ID of your network from being sent out indiscriminately to your neighbors and anyone else in range.

It is handy to have this broadcast ability if you’re running an internet cafe or other public Wi-fi setup, but for home use it should always be disabled.

You can also limit access to your network based to pre-defined ethernet (MAC) addresses. Basically, you tell your wireless base station to only accept messages from a known list. If the address isn’t on the list, the access point shouldn’t talk to it.

Not sure how tech savvy you are. MAC addresses look something like 00:0C:76:1B:0B:8D

On an Apple, if you pull up a terminal you can type in “ifconfig -a” and get your MAC address. Or do it through the GUI. I have no idea where they keep it.

Passwords, encryption and a controlled access list of MAC addresses will give you all the protection you can reasonably need. If you need to restrict access more than that, you probably shouldn’t run wireless.

All good suggestions! Thanks all!