# RF penetration through block walls



## Easy (Oct 18, 2017)

I have a customer who would like to control some RGB light strips with an 4 zone RF controller. I'm somewhat concerned that one of the zones might not work very well or even work at all. The signal would need to penetrate cinder block that has some rebar and the cores are filled with concrete. I'm just wondering if anyone has much success with this. 
It's a built in BBQ with 1" granite top. I installed 2 color wheels on the original install but he wants a remote to control all the RGB lighting in his back yard.
Here is a photo of what the BBQ area looks like.


----------



## splatz (May 23, 2015)

It really depends. Block and metal can stop signals dead. You'll get no signal in an electrical room from a strong wifi antenna in the next room. But UHF radios work 20 floors away in the same building. Many times enough signal gets around the barrier and reflects enough on the other side that you're fine. You might get zip at first but with some repositioning or using a little sheet metal for a homemade reflector you squeak by.


----------



## NoBot (Oct 12, 2019)

Lay it in place temporarily and test it


----------



## Easy (Oct 18, 2017)

Thanks for the input. I guess all I can do is try experimenting. I imagine that the US military has RF equipment that can penetrate block walls. I doubt that the cheap controllers I get off e-bay that are all coming from China will work very well at all. I will experiment with what I have and see what happens. I have several units I can play with. Perhaps I could go with an IR unit instead and drill a small hole in the block so that the receiver can stick out and he could point a remote in it's direction and activate his strip lights. I will try the metal reflector as well and see if it helps with the RF.


----------



## MotoGP1199 (Aug 11, 2014)

I don't deal with this much but back in the day we used a system called X10 that communicated with RF signals and would work on stuff in older houses that new WIFI would not. I'm not sure how well this would work with RGB lights but it might be something to look into.


----------



## splatz (May 23, 2015)

MotoGP1199 said:


> I don't deal with this much but back in the day we used a system called X10 that communicated with RF signals and would work on stuff in older houses that new WIFI would not. I'm not sure how well this would work with RGB lights but it might be something to look into.


X10 is still around, it ran the signal over the power lines, it worked to some extent once they got the kinks out of it but it's not very popular. 

Things like Caseta use wireless but not wifi to communicate, the frequencies don't have (or need) much bandwidth but they penetrate well enough and function in many commercial buildings with a lot of concrete and steel.


----------



## Easy (Oct 18, 2017)

I remember the X10 home automation stuff. I just went to their site and they have some neat stuff. 
It would work quite well for single color LED strip lights but the RGB / RGBW strips need 3 or 4 switch legs. 
All of the switching is done on the load side of the power supply, typically 12 or 24 vdc. Of course they do have 120v strip lights that are good for long distance but even they do all the switching via the controller.

I need to control color, dim and create pulsating light. ha ha 
I bet a ya a ham sandwich the controller I ordered should work.


----------



## Rainwater01 (Oct 6, 2015)

Look up Insteon. I’v installed tons of it. It has its own wired and wireless network for redundancy. It’s much more robust than x-10. I put some in a garage and a house 250’ away from each other. 350’ or more wire feet away and it works flawlessly. Metal siding on both so I’m sure it’s communicating over the wires exclusively in this situation. They’re on the same poco transformer so the signal passes right on through. 


Sent from my iPhone using Tapatalk


----------



## Rainwater01 (Oct 6, 2015)

Easy said:


> I need to control color, dim and create pulsating light. ha ha
> I bet a ya a ham sandwich the controller I ordered should work. [/
> 
> It won’t do the color. Never mind.
> ...


----------



## Easy (Oct 18, 2017)

Here is a link for a radio transmitter and receiver that claims to have a range of 300 meters or 330 feet and the cost is about *$100* and has multiple outputs and individual switches for each. 
Unfortunately it's not really what the home owner is looking for but it might be useful in other applications.
Here is the link ...
I'm actually going with this product but it would be nice if I could find an actual RGB RF controller with a small antenna then I could simply drill a hole in the block and place the antenna into the hole.
Here is that link


----------



## drsparky (Nov 13, 2008)

It all depends on the frequency, the lower the frequency the better it travels through solid objects.
An seismic waves from earthquake are less than 10 Hz and will pass through the earth, that's why they are detected half the world away. Loud base from music passes through walls and the higher frequency sounds get somewhat muted. Light is on the other end of the frequency spectrum frequency and is stopped by a thin sheet of aluminum foil.

Low RF frequency like RC cars are in the 27 MHz range and pass through walls rather well. Garage door openers are in the 300 MHz range and pass though doors but not so well through block walls.
A 2.5 GHz wireless router passes through walls better than a 5 GHz wireless router (the 5 GHz is faster though)
They new public safety cell phone frequency (FirstNet) is in the 700 MHz range because it travels in buildings much better than the 2.5 GHz cell signal. The 5G cell system is very fast , it is in the 28 GHz range but does not travel well i though objects, that's why they need to put more cell towers to cover the same area as 4G.









are closer together.


----------



## Easy (Oct 18, 2017)

drsparky said:


> It all depends on the frequency, the lower the frequency the better it travels through solid objects.
> An seismic waves from earthquake are less than 10 Hz and will pass through the earth, that's why they are detected half the world away. Loud base from music passes through walls and the higher frequency sounds get somewhat muted. Light is on the other end of the frequency spectrum frequency and is stopped by a thin sheet of aluminum foil.
> 
> Low RF frequency like RC cars are in the 27 MHz range and pass through walls rather well. Garage door openers are in the 300 MHz range and pass though doors but not so well through block walls.
> ...


Thanks Drsparky.. This was very helpful information and it was very easy to understand with the examples you presented. 
It's unfortunate that most of the transmitters or receivers for RGB lighting don't spec out the frequency range. 
They only list the size, weight, voltage, wattage and how their product is the best.


----------



## Rainwater01 (Oct 6, 2015)

Do you have Wi-Fi out there?


Sent from my iPhone using Tapatalk


----------



## cuba_pete (Dec 8, 2011)

I understand what everyone is posting and can appreciate the theory, but unless you test it for yourself you won't really know.

I work in the basement of a top-secret military facility...no sh!t, I swear. We have 12" poured exterior walls with four layers of rebar welded at every joint, the roof is thicker, denser, and corbeled (lots of concrete and steel). My office is through another 8" wall, same treatment. I can pick up and use cellular in my office. I can sit in my office with a Keysight MXA signal analyzer and detect wifi and bluetooth up to 25 meters away from someone walking down a nearby passageway wearing an Apple Watch...through an 8" poured wall, and two interstitial offices. That's not just a detection...I'm capturing MAC's with a monitor mode setup, all day long.

While conducting an instrumented survey, I could see the wifi from the touch panel on one of our chillers over a hundred feet away on a separate floor _through _several thick concrete walls and steel/concrete filled doors.

I've come to learn that damn near anything is possible with RF if you send it correctly and pay attention to receiver setup. I'm trying to detect and _preclude_ these things and it's a daily struggle.


----------



## Rainwater01 (Oct 6, 2015)

cuba_pete said:


> I understand what everyone is posting and can appreciate the theory, but unless you test it for yourself you won't really know.
> 
> I work in the basement of a top-secret military facility...no sh!t, I swear. We have 12" poured exterior walls with four layers of rebar welded at every joint, the roof is thicker, denser, and corbeled (lots of concrete and steel). My office is through another 8" wall, same treatment. I can pick up and use cellular in my office. I can sit in my office with a Keysight MXA signal analyzer and detect wifi and bluetooth up to 25 meters away from someone walking down a nearby passageway wearing an Apple Watch...through an 8" poured wall, and two interstitial offices. That's not just a detection...I'm capturing MAC's with a monitor mode setup, all day long.
> 
> ...


I would think that rf would go through concrete and rebar much easier than a solid sheet of metal siding. Is that a fair statement? I feel like my cell service is terrible in metal buildings. 


Sent from my iPhone using Tapatalk


----------



## cuba_pete (Dec 8, 2011)

Rainwater01 said:


> I would think that rf would go through concrete and rebar much easier than a solid sheet of metal siding. Is that a fair statement? I feel like my cell service is terrible in metal buildings.
> 
> 
> Sent from my iPhone using Tapatalk


You're not wrong. This would be especially true if the siding were bonded and even grounded.

To my surprise, I can detect cellular and VOR radials at measurement points on ground grids, too.

A faraday cage is usually designed with specific parts of the spectrum in mind.


----------



## Easy (Oct 18, 2017)

cuba_pete said:


> I understand what everyone is posting and can appreciate the theory, but unless you test it for yourself you won't really know.
> 
> I work in the basement of a top-secret military facility...no sh!t, I swear. We have 12" poured exterior walls with four layers of rebar welded at every joint, the roof is thicker, denser, and corbeled (lots of concrete and steel). My office is through another 8" wall, same treatment. I can pick up and use cellular in my office. I can sit in my office with a Keysight MXA signal analyzer and detect wifi and bluetooth up to 25 meters away from someone walking down a nearby passageway wearing an Apple Watch...through an 8" poured wall, and two interstitial offices. That's not just a detection...I'm capturing MAC's with a monitor mode setup, all day long.
> 
> ...


Thanks Pete .. This gives me hope. Do you have air supply in your concrete coffin?
This reminds me of some of the skiffs where I once worked. The floors and ceilings were 12" thick as well. Most of them had ducts above the T-Bar ceiling that penetrated the concrete walls and they had heavy steel mesh, pink sound and above ceiling motion detectors. No Phones or radios of any type were allowed in hall ways or areas leading into the skiffs.


----------



## cuba_pete (Dec 8, 2011)

I’m fine...wear a sweater most times. The small SCIF, however, is muggy hot. We have an upcoming HVAC project in there. They keep trying to jam more and more blades in there...well, they are jamming them in. I finally said enough, we need more A/C. The BOSC put a glorified bathroom fan with a coil to “help”. Gee...thanks.

They want to limit conduit penetrations and their fill is atrocious. It’s always a struggle.

By using fiber we eliminate most problems outside of the cabinets, then follow red/black installation guidance.

I can still see a Bluetooth smart watch from inside to outside of the SCIF. The new spread spectrum is going to be worse.


----------



## paulengr (Oct 8, 2017)

I have had no trouble using 900 MHz in an iron foundry even through block walls and through areas with liquid iron (huge RFI source). 2.4 GHz will penetrate drywall like offices but not 1” steel or solid cinder block. 5 GHz bounces off drywall. BUT MIMO changes that because it works with signals that bounce all over by design, up to a point.

Wavelength is equal to 30 cm divided by the frequency in GHz. So the wavelength of 5 GHz is about 6 cm. Walls under 10% of the wavelength are effectively transparent. So 0.6 cm is about 1/4” so drywall affects 5 GHz and just barely interferes with 2.4 GHz but 900 MHz which has a wavelength of about 33 cm passes through 1” steel plate. That’s not to say that drywall STOPs 5 GHz but it loses power and bounces around through basically any wall and the thicker the worse it gets. At equal to wavelength the wall is almost impenetratable so 6 cm (2.5”) thick walls stop 5 GHz.

Ubiquiti sells 900 MHz versions of their Airmax stuff. Not popular because of speed but it works where nothing else does like with thick walls and pine trees (needles are triangular prisms that scatter radio waves).


----------

