wireless vs. concrete walls - go through or around?

Question

My apartment is bisected by a ~8" thick concrete wall, through the center of which is a doorway.

My ethernet (provided by the building) jack emanates from one face of this partitioning wall. My office is, unfortunately, on the other side.

Is it better to place the wireless router flush with the wall and try to "blast through" or across from the doorway and try to bounce through and into the adjoining room?

Current setup with poor signal reception:

+--------++--------+
|        ||        |    || = concrete wall
|        || office |    PC = desktop
|        ||     PC |    wr = wireless router
|        ||        |     e = ethernet jack
|        ||        |
|        ||   +----+
|        ||   |    |
|              bath|
|wr      ||   |    |
|        ||   |    |
|        ||   +----+
|       e||        |
|        ||        |
|        || bedroom|
|        ||        |
|        ||        |
|        ||        |
|        ||        |
+--------++--------+

Currently I'm running CAT-5 from the jack along the baseboards to the router, which is located there because there is no outlet near the doorway/hall. The CAT-5 is hidden nicely behind furniture and such, which keeps the wife happy... but the signal in the office sucks.

If I lay the router's antennas flush to the concrete wall, can I expect any better performance?

Answer 1

Bounce it through the doorway. The frequency that Wireless operates at is highly reflective off the right surfaces. It also is absorbed by porous concrete (cinder block). Poured concrete with an appropriate surface will reflect the signal, but you aren't going to blast through it at the Part 15 power levels available in most APs. A corner reflector could be built with tinfoil coated fiberboard to direct the signal through the doorway and in the general direction of the office. Place the AP in front of the reflector and turn it for maximum strength at the other end.

I use the microwave absorbtion/reflection properties quite effectively to divide our place of business into two separate wireless networks.

The warehouse is cinder block wall with a metal roof. The general use AP for the office area (for sales reps and employees lunchtime use) is on the other side of the wall and the metal roof of this area waveguides the signal all the way to the front lunchroom where you get nearly full strength at 60 feet and around a 90 degree corner. Each network is totally isolated from each other except at the warehouse door where the thick oak swing door and metal interlaced safety glass do a pretty good job of keeping the two broadcast regions isolated except when someone blocks the door open.

The standard answer for business radio is VHF bounces off mountains, UHF bounces off walls. You use VHF radio out in the field and UHF in city building work where it will go through windows and bounce around inside as long as it has openings to waveguide through. Wireless networking frequencies are even higher yet and so you're not going to blast through any concrete walls with it.

Answer 2

First answer is correct, but it sounds like someone who is not facing the same wifi boundary conditions. Yes, you need to use the door to get through, but no, you're not going to be using foil covered fiberboard.

First thing I would do is assess the concrete. If the concrete wall behind the router is actual poured concrete or brick, that's great. It reflects well off of it. Cinderblock sucks, it just absorbs it. Metal and metalized surface are fantastic, as is. . . metalized GLASS, i.e., a mirror. Step one is to adjust the placement along the present wall for the router probably a bit downward in your diagram. You are multipathing the crap out of your signal to get through the door if it really is concrete, and you want to get the best bang out of each bounce.

If the center wall is cinderblock and the bath wall is just drywall over timberframe, then pull the router about even with the jack (except still on this wall). That gives you a line of sight through to the office PC, except perhaps having to blow through the very corner of the bathroom wall (which it will do happily).

If the center wall is poured concrete, and the bath wall is something bouncy like brick, then you have to be more creative about your multipathing, since you won't go through the corner of the bathroom. You may have to do the same positioning I recommend above, except position an attractive wife-approved large mirror in your hallway between the doorway and your office on the center wall. This may be needed to give you extra bounce.