Poured concrete vs hollow concrete blocks and WiFi signal.

[Soylent]

I'm trying to find some research about Wi-Fi penetration through poured concrete walls compared to hollow concrete block walls.

My theory with hollow blocks is the Wi-Fi signal will penetrate the inner layer of the block, diffuse and bounce around inside the hollow area, thus weakening it too much to penetrate the outer layer.

However, poured concrete walls are solid. It's a single barrier that a sufficiently powerful signal will still penetrate. It may be limited to 2.4ghz, but it should work.

Assuming I'm correct that hollow blocks are practically impenetrable, is there any way to mitigate the effect of hollow concrete blocks? Like filling them up with concrete?

 

[degrub]

water in the concrete will absorb the 2.4 Ghz radiation wave (it is the same as your microwave). The path thickness of the material and density and water content are what matter.

 

[Greg72]

There is plenty of studies about radio waves and different materials. Concrete is denser than wood and has zero to do with water used, it is about materials in the concrete that can contain metals. Materials like Glass and Wood allow for the signal from a radio transmitter to be seen as a stronger signal to a receiver.

 

[Greg72]

water in the concrete will absorb the 2.4 Ghz radiation wave (it is the same as your microwave). The path thickness of the material and density and water content are what matter.

When concrete is dry, there is no moisture in it, unless it is being saturated.

2.4ghz is a longer signal wave and will penetrate materials better than 5ghz, which is a tighter signal/sine wave.

 

[dosborne]

The amount of rebar used may be a factor

 

[degrub]

There is plenty of studies about radio waves and different materials. Concrete is denser than wood and has zero to do with water used, it is about materials in the concrete that can contain metals. Materials like Glass and Wood allow for the signal from a radio transmitter to be seen as a stronger signal to a receiver.

True, better permittivity and lower reflection than cmu or concrete panel, so the OP should just install an ordinary glass window in the cmu and place his wireless AP in line-of-sight to where he is trying reach. May even work during a hurricane when the window is covered.

Don't forget to install a lintel above the window frame to transfer the loads. ;-)

 

[Greg72]

I would just use an external AP that is made to work in those kind of environments. It is all about budget and with the window, they would have to have one spec’d for high winds and dangerous objects that may hit it.

 

[Greg72]

The amount of rebar used may be a factor

Not every concrete wall requires rebar. Poured walls have zero rebar inside, except the first 18-24” at the footer to stabilize it from “Walking” from hydrostatic and earth pressures. Even CMU and other forms/wall products do not have rebar, other than what is from the footer to keep them from walking.

 

[sfx2000]

My theory with hollow blocks is the Wi-Fi signal will penetrate the inner layer of the block, diffuse and bounce around inside the hollow area, thus weakening it too much to penetrate the outer layer.

Not how RF works in the 2.4 and 5GHz band. It's not going to bounce inside the cavities of the concrete blocks. Rebar in the wall isn't really an issue either.

Concrete Walls - about 5 dB loss, a bit more than Sheetrock, but less than Plaster/Lath - plaster has "chicken wire" to support it, and the metal there is a good match for 2.4GHz, and 5GHz is similarly impacted.

 

[dosborne]

Not every concrete wall requires rebar. Poured walls have zero rebar inside,

The "amount" in some cases would be zero then.
Geez it was meant to be funny, that's why there was a smiley face.