Bad cell phone signal reception is something everyone has to deal with, both home users and business users. There is a lot of conflicting information out there and I often have to explain how cell phone repeaters and other cell phone booster solutions work and what doesn’t to my family, friends, and co-workers. I have very good first hand experience with some solutions and since it is technology related, I have decided to dedicate a post here on my blog about these cell phone reception solutions to point everyone to. Saves me from having to say the same thing over and over when I could just email them a link.
First, for those people that are not regular readers of my blog, I have to let you know I work in IT infrastructure so cell phone engineering is not my expertise. I do some telecom and VoIP work but I am not an RF Engineer that works for a cell phone carrier by any means so please don’t consider me an expert on this subject. I’m only going to tell you about my own experience and research.
Second, I live in the Houston, Texas area. Cell phone coverage depends on your carrier and how their cell tower coverage is in your city. Houston being the fourth largest city in the United States has very good cell tower coverage from all the big carriers: AT&T, T-mobile, Verizon, Sprint, & Nextel. So parts of this post may or may not apply to you depending on where you live. Please do your research before spending your money and don’t rely soley on my blog post.
The Cause of Bad Reception
The question I get asked a lot is how can I improve the cell phone signal in my house or my office because I get 0 bars. In Houston, it is rarely a cell phone tower coverage issue. Cell phone towers are everywhere in this city. People just usually don’t notice them. But if you really start paying attention, you can’t go more than a few blocks before spotting one. Most of the time I hear complaints from friends and family that have just moved into a new house (newly constructed home) about cell reception being poor or 0 bars. They wonder what the cause could be in their brand new house because their old house didn’t have signal issues. The reason for this is because new homes use better radiant barriers in the attic than older homes. Especially in hot places like Texas. These radiant barriers are the cause of the poor signal, not cell phone tower coverage. They are blocking the cell phone signal from penetrating the house. Almost all home builders in Houston use LP TechShield radiant barrier:
David Weekly Homes, Newmark Homes, etc. to even smaller custom home builders all use it here in Houston. TechShield can save you a TON of money per year. I went from having a $900 per month electricity bill in the summer in a house with no TechShield to less than $200 in a newly constructed home with TechShield installed. And the new house has double the square footage! Though TechShield works great and will save you a lot of money on your energy bill, the downside is it block RF signals (radio frequency signals). RF signals is how your cell phone talks to the cell tower. Specifically Ultra High Frequency or UHF. So what a lot of my friends, family, and co-workers find is that when they go home, they go from having 5 bars outside to 0 bars inside their homes. You can confirm TechShield is the cause by going into your attic and looking up. You will see the silver radiant barrier and it will say TechShield on it like this:
With businesses, the taller your building is and the more steel, insulation, and other dense material it is constructed with, the less signal you will get. In some cases like hospitals and large medical centers there could be equipment causing poor signal too. A lot of the big skyscrapers in Downtown Houston and the Medical Center rarely get good a good cell phone signal without working with carriers to install commercial in-building cell phone repeaters on every floor. I will go over what cell phone repeaters are exactly in the next section.
The Wrong Solution
A quick Google search will tell you cell phone boosters or cell phone repeaters are the way to go to solve bad cell phone signal issues. Those stickers and other solutions that are “passive” are all garbage. You need something that is “active” and amplifies the signal which is what a cell phone repeater is. Another term for a cell phone repeater is a BDA or bi-directional amplifier. For home users, you can even buy cell phone signal repeaters at electronic stores like Fry’s or Best Buy. They are cell phone amplifiers that amplify the weak signal from cell phone towers. Usually you stick an antennae on your roof that pulls the signal in, which is connected to the amplifier inside your home which amplifies the signal, which is then connected to another antennae inside your home that your cell phone connects to. Here is a diagram of how a simple cell phone repeater system works:
One thing you will not be told about these is that though they are completely legal to purchase, they are illegal to operate. The reason is cell phone carriers pay tons and tons of money to the FCC to license radio frequency spectrums (cellular frequency spectrums) for their use. You are not allowed to broadcast on these licensed frequencies without permission from the carrier that has licensed the spectrum or you will be fined by the FCC. The problem with a lot of cell phone repeaters is that they amplify the signal, sometimes way too much. This can cause issues with a nearby cell phone tower and causes problem for the carrier. For this reason, they do not want consumers installing and operating in-building cell phone repeaters in their homes. I speak from first hand experience so let me continue.
Amazon, Best Buy, Fry’s and a lot of other stores and websites sell dual band cell phone repeaters and boosters. They are usually dual band meaning it will work with 800 Mhz and 1900 Mhz bands which is AT&T and T-mobile respectively in the US. My friend’s 2 story 5,500 sq. ft house was currently getting 0 bars inside the house due to TechShield radiant barrier. Up to the front door, we could get 5 bars on AT&T and T-mobile phones. As soon as we stepped into the house, the signal drops. He specifically wanted coverage in the kitchen and living rooms only because that is where most of the family usually is. Having 0 bars in the house was unacceptable. If there was an emergency at work or with family everyone has his cell phone number and will call it first. Also he did not have a land line since his whole family had cell phones. So he purchased the zBoost YX-545 unit for around $270 from Amazon.com.
You will see a lot of reviews online ranging on this unit and it’s predecessor the YX-510 from horrible reviews to 5 stars. It all depends on your building, cell tower coverage, and installation. I personally saw very poor results when my friend set it up. Within 5 ft. of the unit, I went from 0 bars to 2 bars. As soon as I stepped out of this 5 ft radius, I got 0 bars again. He called their support line which was very helpful and they confirmed everything about the install was correct. He even sent them pictures of how the antennae was mounted outside on the roof and into the house. But, that’s the best he could get in the house.
So both of us being geeks, I convinced him to try upgrading the unit. He bought the premium kit with upgraded outdoor directional antennaes for $130. You can use this to get a better signal from the cell tower because you can point it directly at it:
We also upgraded the thin RG-59 coaxial cable the kit came with to some nice thick RG-11 cable:
The tradeoff is the RG-11 is less flexible so it is harder to run the cable through walls or attic all the way up to the roof. Imagine RG-6 (the cable you use to connect your to your TV or cable box for cable TV) but twice as thick.
After getting all the new upgrades installed, we could get 3 bars within about 10 ft. As soon as we leave that radius, the signal drops to 0. At this point zBoost support did not have any other suggestions for him except to move the directional antennae on the roof and point it directly at another cell tower. We had already mapped out where the AT&T and T-mobile cell towers were by using Google Maps and a cell tower locator application for our phones called “Cell Tower Locator”. We also drove by the cell tower sites to confirm we were connected to it and measured the dbm as we approached and left the tower. There are also websites online that document cell tower locations and we confirmed the locations of the towers there as well, it was only 1.3 miles away. He even rotated the antennae on a mast at 5 degrees each for the full 360 degrees testing and that was the best he could do. So it wasn’t a problem with my friend’s antennae pointing for sure.
So again, he opted to upgrade but this time to a business solution that is used for large office buildings, warehouses, etc. One really popular cell phone repeater company that caters to home users and business users is Wilson Electronics but he opted to go with Cellphone-Mate that makes a comparable product with excellent reviews. There was a company locally that installed both Wilson and Cellphone-Mate in office buildings and they recommended going with Cellphone-Mate for his house. He decided to go with their flagship product, the SureCall CM2020 68dB amplifier for $1200. They claim to cover 60,000 sq ft on their website:
and that it is FCC approved to the max output of 3 watts. But keep in mind they are talking about the output of the device being legal per FCC regulation. They do not say operating the amplifier itself is FCC approved and as I mentioned above, it is illegal to operate an unauthorized cell phone repeater/amplifier. He did not know this of course when purchasing the unit for $1200. They told him on the phone as well as on their website that their basic CM2020 kit can cover up to 10,000 square feet easily and they have done many installs for businesses and hospitals. Up to 60,000 sq ft. that the manufacturer’s website said was with multiple antennae upgrades and such that was overkill for a home. He purchased a complete top of the line kit consisting of the following:
-68 dB CM2020 amplifier
-Outdoor directional yagi antennae
-Indoor omnidirectional dome antennae
-LMR400 cables (really thick coaxial cable)
You can see it here:
My friend purchased it locally and got the company to come out to install it. Instantly his 5,500 sq ft. house was at 5 bars. Anywhere in the house was a solid 5 bars, no drops at all. The company tuned down the 68 db gain using the dip switches on the front of the amplifier to a level that was just enough to cover the inside of the house only.
Now the problem came a few days later when he received a certified letter from an RF engineer from one of the major cell phone carriers. In the letter the RF engineer stated that since the day the unit was installed, it has been causing interference with a nearby cell tower. It was causing all sorts of problems for that carrier’s customers in the area. So they had sent this RF engineer out to investigate. Using a directional antennae in his van and some other hardware, he discovered the source of the signal was my friend’s house which is why he sent the letter. He went on to explain cell phone repeaters (aka BDAs) are not permitted to be installed for use on any cell phone spectrum in the US by the FCC without consent from the carrier that licenses (T-mobile, AT&T, Verizon, etc.). None of these carriers permit the use of a BDA by a home or business user. Only the carrier themselves installs them and it’s a huge process and very expensive to have them do it so only large corporations tend to do this. My friend called the RF engineer and got more info on this. They typically install licensed BDAs themselves or subcontract the work out to companies like the one that my friend had hired to install the unit.
In fact a few months ago while working in one of the largest skyscrapers in Downtown Houston, I ran into a T-mobile subcontractor that was going from floor to floor testing the building’s repeater signal. They had several of them per floor that fed into an IDF closet that ran throughout the building and into several amplifiers on one level. Something like this:
Anyhow, operating a big system like above or a simple system like my friend started off within his house on your own is illegal. Only the carrier which is the licensee of the spectrum is allowed to do it. Quick research online shows several cases of FCC inspectors imposing fines and seizing cell phone repeaters that were installed by home and business users without authorization. They typically start of with cease and desist letters like below:
Here is the important part in all these cease and desist notices:
“Licensees may install in-building radiation systems without applying for authorization or notifying the FCC, provided that the locations of the in-building radiation systems are within the protected service area of the licensee’s authorized transmitter(s) on the same channel or channel block.”2 A licensee’s authority to install a BDA does not permit a subscriber to install a BDA, unless that subscriber has received explicit authorization from the licensee to do so. In response to an inquiry from an FCC agent, T-mobile reported that it did not provide you authorization to install a BDA. Operation of radio transmitting equipment without a valid FCC authorization or license is a violation of Section 301 of the Communications Act of 1934, as amended,3 and may subject the responsible parties to substantial monetary forfeitures, in rem arrest action against the offending radio equipment, and criminal sanctions including imprisonment.”
These “notices” from the FCC go on and one if you do a Google search for “FCC BDA notice”. I’ve found them from just a few weeks ago to even as far back as 10 years ago. You will notice that most of the complaints above are to home or business users. Some are even found on boats. I even found one to Sony Pictures Studios in Los Angeles so even a huge company can land in hot water. One really interesting find, there are some notices from the FCC stemming from carrier to carrier complaints! So even one carrier installing a repeater that interferes with another carrier’s signal is a real issue and the FCC has to step in to correct it.
Luckily, the RF engineer was extremely nice in informing my friend of the laws in his letter and on the phone and the company that installed the unit had a 30 day return policy and removed the unit within a day. Apparently, this happens a lot in the Houston area. Consumers go and purchase cell repeaters (or BDA which is the “official” term) from Amazon or Best Buy and install them. Then he has the headache of hunting them down and requesting the business or home user to remove it. If they don’t, he then requests help from the FCC and they said a notice to the user like above. Poor guy. Working in infrastructure myself, imagine end users running amok on your network causing it to go down every day. This is what he had to deal with on a daily basis. I did not envy him.
The Right Solution
So now my friend was stuck. After spending 2 months experimenting with cell phone repeaters and finding out their operation was not allowed, he was back at square one. So I ended up doing research for him and found another solution called a femtocell I pointed him toward:
It is basically a small device about the size of your router that sits in your home. Your cell phone will connect to the device instead of a cell tower. The device then connects to your carrier’s network through the Internet using a secure tunnel. So you will be making the phone call over the Internet and not rely on a cell tower anymore. Currently AT&T, Sprint, and Verizon all use this technology. Since his family was on an AT&T family plan, he purchased their solution called the AT&T MicroCell:
The device itself is manufactured by Cisco so you know it’s a solid piece of networking equipment. It cost a one time fee of $150 and there were no charges after that. Plus AT&T gave him a 30 day trial. I was there the day he got it in and after following the simple setup procedures, we turned it on. It took a about 5 minutes for it to get a GPS signal (for Enhanced 911 purposes) and to establish the VPN tunnel with AT&T’s server. Within a few seconds of all lights going solid green, all the AT&T phones that were registered to use the device had 5 bars inside the whole 5,500 sq ft. house! A $150 femtocell unit was doing the same thing a $1200 cell phone repeater was doing! Both of us were floored. All that time and money he spent on installing was a complete waste. He’s been using the AT&T Microcell for about 8 months now and is extremely happy with it.
One thing to note, I mentioned earlier in this post that dual band repeaters work on two spectrums. But sometimes carriers that offer high speed data operate those services on a different spectrum that is not amplified by the repeater so you will get little or no high speed data when you are around a repeater. For example, T-mobile uses 1900mhz for voice and slow EDGE data service in the US but 1700/2100 MHz for high speed 3G data service. When you go with a femtocell from the carrier that doesn’t rely on cell towers, you don’t have to worry about frequency bands and data, everything goes through the Internet and you will get the high speed data service you pay for!
By the way I mentioned above every major carrier has femtocell except T-mobile. I read an article that they were testing them though. For now, look into T-mobile’s feature called “Wi-Fi calling” which is similar to femtocell but this requires you have a special phone that can make calls over WiFi. Read about it below:
Go to :
and click the “Wi-Fi and Mobile Calling” checkbox in the left hand bar to see all the phone that have this feature.
Do your research before investing money. My friend and I are both geeks, and he makes a lot more money than I do so he doesn’t care about throwing money away experimenting. If you live in a rural area with no cell phone towers around, using an unauthorized BDA or cell repeater will likely not mess with a carriers’ network and you probably won’t get a letter from a carrier or the FCC. But if you live in a highly populated city like Houston with cell towers everywhere, the chances of your repeater causing issues is much higher. Cell phone repeater companies will say “FCC approved” on the device but again as I mentioned earlier in the post, they are talking about the device itself, not it’s operation by you. So it is risky to use one and I would personally never attempt it.
Luckily for us, femtocell technology is available from most carriers and works just as well as an enterprise level cell repeater and for a fraction of the cost. So now my friends, family, co-works can read this article and I don’t have to keep repeating my story over and over again. And everyone else reading this, please do post if my experience helps you any. I’d also really love to hear from any RF engineers that work for any carriers about their own experiences and recommendations.