nRF24l01+ Through Concrete

RE: nRF24l01+ Through Concrete

guillermo — Fri, 15 Nov 2013 19:41:43 GMT

hola mi pregunta es al equipo de hadware nordic se puede cargar un telefono movil solo con señal wifi absorbiendo las señales vecinas o colindantes gracias

RE: nRF24l01+ Through Concrete

Ole Morten — Thu, 01 Aug 2013 09:55:00 GMT

Since this discussion doesn't really have a definite answer, I'll just mark it as resolved, without accepting any answer, just to clean up things.

RE: nRF24l01+ Through Concrete

RAB — Wed, 03 Jul 2013 14:25:53 GMT

Thanks for the replies. I knew that the concrete would absorb a fair amount of the signal but I did not expect it would be that much. Really it looks like my only option would be to add an external power amplifier to boost the 0 dBm output of the nRF24l01+. Unfortunately, this would require a redesign and new certification testing, so it is not possible.

RE: nRF24l01+ Through Concrete

Marc Nicholas — Wed, 03 Jul 2013 13:55:07 GMT

My home was built in two separate phases (bear with me here). Because of that, I have an original concrete block foundation and then an additional foundation has been added on one side. My lab and office are located in the "new" part below grade, and as such it is surrounded by the concrete foundation.

I'm using BLE (nRF51822) for my application and I can't get any signal through even this relatively porous foundation. As the previous poster pointed out, there will be some attenuation due to the rebar, but even the concrete itself introduces propagation issues for 2.4GHz. I believe your average concrete wall or floor is generally considered to introduce ~30db of attenuation.

These concrete walls won't actually be a Faraday cage as I doubt the rebar is grounded and the mesh size would need to be much, much smaller than found in concrete work (unless you happen to have rebar that has a 1/4" mesh). But as I mentioned, it'll add to attenuation and introduce scatter too.

For an example of a true Faraday cage in the mid-Ghzs, go to your kitchen and look at your microwave oven :)

Cheers,

-m

RE: nRF24l01+ Through Concrete

Pål Håland — Wed, 03 Jul 2013 06:33:13 GMT

If it is only concrete, then there should not be too much problems. However if it is reinforced concrete, it depends on how small the reinforced steel grid is, because it would act as a Faraday cage. The smaller the grid, the better blocking of RF high frequency signals.

(Link to a similar question about WiFi (same 2.4ghz frequency) superuser.com/.../does-it-make-sense-that-the-lower-a-router-is-to-the-floor-the-worse-my-recepti

en.wikipedia.org/.../Faraday_cage