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Measuring Cell Phone Signal Strength

What does signal strength have to do with anything? The thing to remember about cell phone signal boosters is that they only work if there is a cell phone signal to boost. Boosters need something to boost. So how much signal is enough signal to boost? How do you measure the cell phone signal strength? In order to determine if a signal can be boosted, we first need to understand how cell phone signal strength is measured. Let’s go over a few things and see if we can figure it out.

cell phone signal strength

How You Measure Cell Phone Signal?

Cell phone signals are measured in units called Decibels (dB). If you have been racking your brain trying to figure out an activity only slightly more interesting than watching paint dry, you could hop over to this Wikipedia page about the Decibel. Decibels are basically a really neat way to make really, really big numbers and really, really small numbers more manageable.

Let’s pretend that you have a cellphone tower outputting a signal at a frequency of 850 MHz. Imagine that that signal was 1 Watt at output. According to the Free Space Path Loss formula, at a distance of 1 Kilometer from the tower a receiver would pick up that signal at 0.0000354 Watts.

Free Space Path Loss Equation
Free Space Path Loss Equation

If that distance was 2 kilometers (double), the signal would be picked up at 0.0000176 Watts. It doesn’t take a genius to recognize that 0.0000354 and 0.0000176 are very unreasonable numbers to have to work with. So, some genius decided to create a much easier way to quantify these numbers. And thus the unit of Decibels was born.

If we were to convert these results to decibels, our two answers above are now much more easily displayed as -89 dB and -95 dB.


A few quick thing to note. Notice with the example above, at 1 kilometer the signal strength is -89 dB. At 2 kilometers the signal was -95 dB. Looking at this reveals something very interesting. Notice that when we doubled the distance from the cell tower, we lost 6 dB of signal.

Every time we double the distance from the cell tower we drop 6 dB of signal. Another interesting point is that for every 3 dB, we double the power. For example, if we had a tower putting out 1 Watt of power (30 dBm), then double the power, 2 Watts would be 33 dBm.

We measure cell phone signals in dBm. A “good” cell phone signal is anywhere from -50 dBm to -110 dBm.

How To Measure dBs?

There are a few different ways to measure cell phone signal to determine what kind of signal strength you are receiving.

  • Look at the little bars on your cell phone.

Looking at the little bars on your cell phone is the least effective way of determining what kind of signal you are receiving. The little bars on your cell phone update occasionally when the cell phone signal changes. It can take several minutes for the cell phone signal bars to change on the phone display.

  • Put your phone into “Field Test Mode.”

Both Android and Apple phones have the ability to show you the actual cell phone signal level that they are receiving from the tower.

On an Apple phone (if you have an iOS version older than 11), you can enter “Field Test Mode” by dialing *3001#12345#*. This will open up a special Field Test Mode app that will allow you to see the signal strength in decibels. You have iOS version 11 or later? You are hosed. For some unknown reason, the all-knowing beings at Apple have decided that you no longer need access to the ability to know what decibel your signal strength is.

On an Android phone, you can see what your signal strength is by accessing the settings of your phone. Navigate to the status section and you should see a signal strength reading.

  • Use a SureCall Signal Meter.

SureCall RF Signal Meter SC-METER-01 with Antenna

The best way to see your actual signal strength level is by using a SureCall signal strength meter. This meter is a device that will allow you to see the signal strength for any cell phone band.

Signal Size Matters

Signal strength is an important part of the whole signal booster scene. If you know what your cell phone signal strength is, then you can get a pretty good idea of how well your cell phone signal booster will work.

For example, if you are looking at a 50 dB Fusion2Go 2.0 RV cell phone signal booster kit, you can get a pretty good idea of what your signal level will be after the booster does its job. If I start at a -100 signal level and I boost it by 50 dB, then I can expect about a -50 dB signal right next to the booster.

If you are an installer or you have a reason to constantly take super accurate readings, it might be a great idea to add the SureCall Signal Meter to your toolbox.

I happen to sell the SureCall Signal Meter here in my shop if you are interested in being the proud owner of one.

At any rate, if you have any questions about cell phone signal boosters or if you need any help on deciding which booster is right for you, feel free to drop me an email to:

Thanks for stopping by!


RV Cell Phone Signal Boosters

I got my start in radio when I was young. What does it possibly have to do with RV cell phone signal boosters? I have no idea, but it’s kind of an interesting story how it all started.

Old School Ham Radio

One of my friends, Mike, had discovered a flaw in the attendance system at school. Mike set up an appointment to “job shadow” at a radio station, he was a music buff. I quickly jumped on board when I realized that we were going to be able to skip school with an excused absence.

Radio fascinated me when I toured the station. I asked the tour guide, Bryan Hyde, how a young, wide-eyed individual such as myself would be able to get started in such an industry. I was informed that occasionally, youngsters willing to get paid next to nothing were needed as “board-ops.” Board operating left me manning the control board in the studio, patching through whatever was supposed to be on the air. When Rush Limbaugh finished his perfectly timed outro into the local commercial break, it was my job to quickly take him off the air and fire our local commercial spots.

Board operating was power, but it wasn’t the coolest thing to do at the radio station. Sure, if you wanted to make money, there was always a gig in the sales department, but on-air was where all the fun was. Just being a sales person didn’t allow me the clout to say, “Don’t you know who I am?” to someone that tried to short me on the amount of meat on my sandwich.

Paying Your Dues

In those days, being able to have your actual voice heard on the airwaves took a lot of training. The older fellers called it “paying your dues.” In those days, being a radio jock was something awesome! Eventually, I talked someone into mentoring me.

I finally got a break when I moved to the radio station across town. It was a smaller radio group. No sooner had I moved over there than our radio group was purchased by the group that I had just left. “No one would lose their jobs,” we were told.

As a newlywed, when I saw people (that weren’t going to lose their jobs) start to get canned, I thought it expedient that I find a more secure position. I heard about an opening in the engineering department. I tried it out and it changed my life.

Working as Gary Smith’s apprentice, I learned a ton of great things. But I lacked the knowledge I needed to truly understand the technologies that I was working with. That’s when I decided to go to college.

Back to RV Cell Phone Signal Boosters

Eventually, that decision to go to college landed me at a job where I got to design and test cell phone signal boosters. I was able to take part in several really amazing projects! And I learned about what I believe is an amazing, untapped market. Everyone has a cell phone, and at some time or another everyone has experienced the anger of dropping a cell phone call exactly in the middle of something very important.

While I don’t yet own an RV (read about how I will someday here in my post about CellBooster and FMCA), I have been camping a time or two. In fact, last summer I visited the majestic Grand Tetons and the amazing Yellowstone National Parks with my family. It was my first time. I was blown away by the grandeur and the sheer awesomeness of nature.

While trudging through Yellowstone with a 3-year-old on my shoulders was less than a picnic, it was definitely worth the many subsequent trips to the chiropractor to realign my spine afterwards. My 3-year-old is a bit of a handful. I told him that bears eat “little boys that don’t listen to their daddies,” and it seemed to work to keep him from running off. Although, now whenever he’s “not being a listener” he runs to the window to see if there’s a bear outside our back window (we live in the desert). I may have scarred him for life.

Really Back to RV Cell Phone Signal Boosters

I noticed that while I was in the wild up yonder, there were several times that I wanted to call my parents to share the beauty with them… Or call my wife to see if she knew where the 3-year-old ran off to. Some times I wasn’t able to get a signal. It would have been really handy to have that SureCall cell phone signal booster.

If you are an RV aficionado, I can imagine that you have been SEVERAL places that you wish you could have a better cell phone signal. That’s where these cell phone signal boosters come in handy. You hook them up in your RV and voila! A terrible signal becomes great!

How Do RV Cell Phone Signal Boosters Work?

Great question! RV cell phone boosters work by using a higher gain antenna on the outside of your RV to collect what little cell phone signal that is coming from the cell tower. Then, it runs that small signal through several stages of amplifiers, filters and magic to make the signal stronger and clearer. Then it re-broadcasts that cleaner, stronger signal through another antenna inside of your RV.

Here’s a diagram with the basic setup:

Fusion2Go 2.0 RV Cell Phone Signal Booster Install Diagram
Fusion2Go 2.0 RV Cell Phone Signal Booster Install Diagram

Directional Antenna

In MOST situations, the Fusion2Go 3.0 RV Kit will work great as is out of the kit. In some situations, you might need to add a few accessories to make it work to its full potential.

For example, John called me the other day. He had a situation where he is trying to use the RV cell phone signal booster directly underneath the cell phone tower for another carrier. The challenge here is that we wanted to block out the overpowering signal and amplify the weak signal from further away. The solution? Swap out the omnidirectional outdoor antenna with a directional one. Aiming the antenna away from the close cell phone tower and towards the one far away tower will clean up the signal.

SureCall SC-230W Wide Band Directional Antenna

The directional antenna has really good gain at the front of the antenna. We call this really good “front to back ratio.” This antenna has a front-to-back ration of about 10dB. Meaning that on the SureCall SC-230W Outdoor Yagi Antenna has about 10 times stronger signal reception from the front of the antenna than it does on the back of the antenna. So by pointing it away from the stronger tower, it will help to block the strong signal and will amplify the weaker signal from the farther tower.

Extension Cables

In another situation, Jim had a bit larger RV. He was rolling in a 43 footer! I’m betting that it’s a beautiful rig! He was sure that the 40-feet of SC-240 cable that comes with the booster wasn’t going to be enough to make the run from the back to the front of the RV where he wanted to place the booster.

SureCall 240 Coaxial Cable FME-FME 10 foot SC-004-10-FF

So we outfitted Jim with a 10-foot length of SC-240 coaxial cable and a 20-foot length of SC-240 coaxial cable section of SC-240 extension cable to let him lengthen the cable a bit to make the run. Whatever your situation is, I’m sure that we can find a solution.

Don’t forget, that when you are ready to buy RV cell phone signal boosters, you can find whatever boosters, antennas or extension cables you’ll need in our online shop.

One more thing! Whatever your particular situation, I am happy to go over it with you. Just send me an email to: and I will be more than happy to answer any questions that you have! This is my passion!

Thanks for stopping by!


Choosing the Right Antenna

With all this nerd talk going on around here with “cell phone signal boosters” and “frequencies” and “gain” and whatnot, it is easy to see that many people can become lost in all of the industry jargon. I call it “engineese” because I consider it a different language. Every NORMAL person in this world could care less about the radio frequency spectrum and how sun spots can impact satellite communications. That’s why God created engineers. It’s what I live for. And lucky for you I consider myself a pretty good translator of the “engineese” dialect. I hope that with this article I will be able to help you choose the right antenna for your project.

In this article, we will go over the basic antenna types and we will discuss when and where you might want to employ the different options.

“Milk Was a Bad Choice”

anchorman cover photo credit:
Anchorman Cover Photo credit:

In Anchorman:The Legend of Ron Burgundy (one of my favorite movies), there is a part where the depressed Ron Burgundy, played by Will Ferrell, finds himself running a marathon. While he’s running the race, he takes a drink out of a milk carton and a curdled clump of milk falls into his mouth as he says, “Milk was a bad choice.” While choosing the wrong antenna won’t cause you to gag and vacate the contents of your stomach, it can leave you with a sour taste in your mouth when it comes to cell phone signal boosters.

Basic Types of Antenna

If you were in a situation where you had nothing left to live for, you could mozy over to and read up on the different antenna types. Clearly, at that point, you would have no need for a cell phone signal booster, because you probably wouldn’t have any friends to make a cell phone call to anyway. Perusing through the site, you would count more than 25 different types of antenna. You would read up on the countless spellbinding descriptions of the different antenna types, and you’d come to the conclusion (as I did) that as far as cell phone signal boosters are concerned, there are 2 basic types of antennas. Directional and Nondirectional.

Directional antennas have greater gain in one direction than they do in another direction. Nondirectional antennas (also known as omnidirectional) have an almost uniform gain in all directions.

You: “Why don’t they just make an antenna that has really good gain in all directions?”

Me: “Great! (in a sarcastic tone) Now I have to explain to you the concepts of gain and some antenna theory.”

What the Heck is Gain?

In my life, gain is the number of pounds I just put on over this most recent Thanksgiving holiday (Seriously, I just put on about 7 pounds this week). In the cell phone signal booster industry, gain means something a little different and you will hear the word “gain” a lot.

As you can probably guess from it’s name, gain is basically a measurement of how good an amplifier (or antenna) converts electrical signals to radio signals and vice versa. While gain is an important factor in determining the “how good” an amplifier or an antenna is, it’s not important to know the intricacies of gain to understand what it is. If you are a glutton for punishment (and you might be if you are still reading this), you can hit up this wikipedia page about antenna gain and dive into all the gory details. Suffice it to say that for the purposes of what we care about, gain is a measurement of “how good” a device is at converting energy.

Basic Antenna Theory

Strap on your seatbelt, because I’m going to try to quickly dive into some basic theory here. In physics and antenna theory, there exists a theoretical “perfect” antenna called the Isotropic Antenna. This antenna only exists in theory because in REAL life there is no such thing as a perfect antenna. But if there WERE a perfect antenna, it would have a perfect gain of one all around the center of the antenna. It would be like a perfectly round exercise ball.

Isotropic Antenna is like an exercise ball
A theoretical Isotropic Antenna is like an exercise ball.

If you were to measure the gain at any point around this perfect antenna, it would measure 1 (one). This would be the perfect antenna, meaning it would have a unity gain of 1 (one) anywhere around it.

Because of physics and physical antenna characteristics, it is impossible for this antenna to exist in real life. In order for it to exist, the energy would have to radiate from a perfect point. Because of connectors, cables, physical characteristics and whatnot, this type of antenna (like world peace or an unlimited Hostess Cupcake supply) cannot exist in the “real world”.

Real Antennas

Now, imagine if you were to balance a 30-pound weight on the top of this exercise ball. The exercise ball would “squish in” at the top and the bottom and would make the exercise ball look more like an oblong shape, like a delicious Gala apple. If you were to measure the gain around the exercise ball now, there would be higher than 1 (one) gain around the sides of the ball and the top and bottom of the ball would have gain of less than 1 (one). No new gain was added or created, we just squished the ball to make more gain on the edges and less gain at the top and bottom. This would be an example of an omnidirectional or non-directional antenna.

The same thing happens with a directional antenna. If we severely squish the exercise ball (like, by having myself lay on it) we would get a severe protrusion to the sides and next to zero gain on the top and bottom (because of my fatness squishing the ball). We didn’t create any more gain, we just moved the areas of greater gain by squishing the ball around.

This antenna gain is measured in dBi, which means “decibels over isotropic”. So if a directional antenna (like THIS wide band outdoor Yagi antenna) has 8 dBi of gain, that means that this antenna, at at least one point around it has a gain of 8 decibels higher than what the ideal isotropic antenna would be.

So… Which is the Right Antenna for Me?

SureCall SC-230W Wide Band Directional Antenna right antenna for far
Outdoor Directional Yagi Antenna- Right antenna for far cell phone towers.
SureCall Wide Band Outdoor Omni 50 Ohm SC-288W right antenna for close towers
Outdoor Omnidirectional Antenna – Right antenna for closer cell phone towers.

Now, if you’re still with me, let’s chat about when you would want to use which antenna. Sometimes you will want to opt for an omnidirectional antenna, and other times you might want to choose a directional antenna. So which is the right antenna for when?

Choose a directional antenna if you know, or even have a pretty good idea of where your cell phone signal is coming from. Then you can aim your antenna at the cell phone tower and “shorten the distance” between you and the tower. There are a lot of great online tools to help you determine where your nearest cell phone towers are. is one of my favorites. If you don’t mind taking the time to adjust your antenna to get you the best signal, and you are not too close to the cell phone tower, a directional antenna is the right antenna for you.

If you have a great cell phone signal outside, but you just can’t seem to get good reception inside, then an omnidirectional antenna is usually the better choice. An omnidirectional antenna saves you the trouble of having to aim your outside antenna, but you sacrifice some gain for the added convenience. But in some areas, where there’s no shortage of cell phone towers, the omnidirectional antenna is better than blasting a directional antenna at the cell tower. In those situations, the omnidirectional antenna is the right antenna for your application.

Switching Up the Right Antenna

Whatever antenna you end up choosing, you need to understand that if your signal booster doesn’t seem to performing like you think it should be, it’s probably because you need to try a different antenna first. With most cell phone signal boosters offering a money-back guarantee (I offer a 45-day money-back guarantee on anything purchased from my shop), there’s almost no risk to trying an antenna on for size. Or better yet, if you are an RV user, or like to take your booster with you, keep both antennas and use whichever works best for where you are at.

I know that all of this information can seem daunting, but know that I am here for you! If you have any questions, need some help picking a booster or antenna, would like to run an idea past a booster expert or need anything else at all, drop me an email at and I am happy to help out!

And, as always, if you are looking for the best place to buy cell phone signal boosters online, you can find everything that you need here in my shop. Thanks for stopping by, I’m excited to hear about your cell phone signal booster project!

– Rob


1973 was a great year! The Vietnam War ended, construction on the Sears Tower in Chicago was completed and the Federal Express was launched. But in midtown Manhattan, there was something even more amazing taking place.

Martin Cooper inventor of the handheld cellphone
Martin Cooper inventor of the first handheld cell phone. Source

Martin Cooper, a Motorola employee, stood on 6th Avenue, between 53rd and 54th streets and made the first cell phone call from a handheld subscriber device. Who did he make this first inaugural cell phone call to? His mother to tell her “happy birthday”? His wife to tell her that he’d be working late and not to wait up? No way! His first cell phone call was to his rival at Bell Labs to ask him how his reception sounded. As an electronics engineer, I can appreciate that sense of competition!

I remember many years later in the early 90’s that my parents brought home our family’s first cell phone. It was a Motorola bag cell phone like this one. My dad was a traveling salesman at the time, and this phone gave us a way to get in touch with him while he was on the road.. IF he happened to be in an area with service. And THAT’S where I first noticed the major flaw in the cell phone system. Cell phones are worthless without the service to power them. If only there were a way to extend cell phone signal in areas that have poor coverage. Enter, cell phone signal boosters!

What do cell phone signal boosters do?

Cellular signal boosters (or range extenders, as they are sometimes called) will always have an input antenna (referred to as the outside antenna) and an output antenna (referred to as the inside antenna). The outside signal is collected, filtered, amplified and then rebroadcast to users via the inside antenna.

SureCall created this amazing graphic that very effectively illustrates the basic functionality of cell phone signal boosters.

graphic depicting the function of cell phone signal boosters
How cellular signal boosters work

This same basic principle is applicable to all different types of cellular signal boosters (home, office, enterprise and vehicle boosters).

While this blog post will not get into the “nitty gritty” of how you do the actual install of a cell phone signal booster (see this blog post on installing cellular signal boosters for more in-depth installation tips), we will briefly discuss the basics.

Outside Antenna

Directional Yagi Antenna
Non-directional Omni Antenna

The functionality (or coverage area) of a cellular signal booster DIRECTLY relates to the quality of the cellular signal received by the outside antenna. A cell phone signal cannot create a signal where none exists. But it CAN help to increase signal where it is poor.

The type of outside antenna and its orientation is crucial to maximize the effectivity of the cellular signal booster. Antennas come in two flavors, directional and omni directional (non directional), depending on your particular situation, you may need to choose one over the other.

For example, if you have great service outside your home, but terrible service inside your home, you will probably want an non-directional outside antenna. If you were to choose a directional antenna and aim it at the cell phone tower, the signal from the cell tower would overpower the booster. This would limit the effectiveness of the booster. On the other hand, if there’s a poor outside signal, using a directional antenna would give much better results inside.

Inside Antenna

Directional Panel Antenna
Non-directional Omni Antenna
Non-directional Dome Antenna

Because inside antennas also come in the directional and non-directional varieties, you may need to carefully consider your choice of inside antenna. If you are going to install the booster near an outside wall, you might go with a directional antenna. Then you could aim the inside signal towards the interior of the building. On the other hand, if you are going to install the booster near the center of the building, you might want to use a non-directional antenna instead.

The Booster

There are quite a few different options for cell phone signal boosters. The main difference in booster models is the amount of gain and output power that a booster is capable of providing. Surecall has a few “flagship” models that come highly recommended (by me… because I have personally tested them).

The following are my favorite booster kits for the respective categories:


Fusion2Go 2.0 Kit
Fusion2Go 2.0 Kit


Fusion4Home Yagi Panel
Fusion4Home Kit With Yagi & Panel Antennas


Fusion5s Yagi Dome
Fusion5s Kit With Yagi & Dome Antenna


Fusion5X Omni 4 Dome Kit
Fusion5X Kit With Omni and 4 Dome Antennas

Need Help?

If you need help figuring out what might be best for your exact situation, we are more than happy to help! Since we understand that not everyone can be an electronics engineer (like me), email us at: describe your situation, and we would LOVE to help you design your cellular signal booster system!

When you’re ready to buy your cell phone signal booster, we would LOVE to sell you what you need! Buy cell phone signal booster here in my shop.