Honestly, you already know if you need a cellular signal booster. If you’re missing calls completely, if you can’t hear the person on the other side or they can’t hear you, or if you can’t stream the shows you want to watch. You already know that there are solutions for problems like this… you just don’t know how bad the problem is. Luckily there are tools that can tell you.
If you’re going to make a career of measuring cellular signals, you’ll want to pick up a SureCall Signal Meter. This is a professional-quality tool that gives you all the information you need, every band and every number. It’s also a little too expensive for most people, especially if you’re expecting to use it only once. There are tools for every iPhone and Android to help you measure cell signal and the best part is they’re 100% free. They may not give you the depth of information you get from a pro signal meter but they’ll help you know how bad (or how good) your cell service is, and help you choose a place for your outdoor antenna.
Bars Aren’t Enough
Those signal strength bars (or dots) on your phone are almost meaningless. They don’t even necessarily correspond to specific numbers and they vary from phone to phone and from carrier to carrier. You may have 3 bars, the person sitting next to you may have 1, and both of you might have problems making calls. Bars may have meant something in the early days of cell phones but they’re just for decoration now.
Real cell signal is measured in “dBm.” dBm is a measure of how strong your signal is compared to one milliwatt (1/1000th of a watt.) Cell signals are always negative numbers, meaning they are less than one milliwatt as required by law. Stronger signals could cause problems for people and animals. The further away from zero the number is, the weaker it is. -40dBm is about the strongest you could get, about what you would expect if you literally laid your phone on a cell tower. -120dBm is about the weakest signal most phones can detect.
Most people in most situations can make calls as long as the signal strength is -100dBm or better, which corresponds to .000001 watt of signal received. Take a minute and think about that for a moment, because it’s pretty impressive. If you had a light bulb using .000001 watt, you wouldn’t even see the light. Yet, your phone can actually stream Netflix with such a weak signal.
It’s important to measure real signal strength in dBm, and it’s important to know what part of the signal you’re measuring.
Before You Start: Turn Off Cellular Data?
Most cellular boosters made today will boost both voice and data for all major carriers (except Sprint.) If you don’t need to boost data frequencies, you can save money by choosing a voice-only signal booster like SureCall’s EZCall. These boosters only work with voice frequencies so they don’t need as many complicated pieces of hardware inside.
If you only have problems at home and you always connect to Wi-Fi, you probably don’t need to boost the data signal. If you’re using Sprint, unfortunately your data network is a maze of different frequencies that are unlike anything used by other carriers. Either way, a voice-only booster is your best choice. The key is making sure that you’re measuring voice frequencies. To do that, turn off cellular data on your phone.
On an Android, go to Settings > Data Usage and turn off Cellular Data. You might get a nag message like the one at left.
On an iPhone, go to Settings > Cellular and turn Cellular Data off. You may get a message at some point about location accuracy. It’s ok to ignore this.
Remember to turn cellular data back on when you’re done, because without it you may not get voicemails, emails, or other forms of messaging.
Measuring Your Signal On Android
There are a lot of free apps on the Play store for measuring signal. It’s also possible to dig into the menus of most Android phones and measure signal without a meter, but since there are so many excellent free apps, I don’t recommend going that way. Just be careful when choosing an app to make sure it’s not claiming to improve your signal, because those apps don’t do anything.
I recommend a free app called “Signal Strength” which lets you test both cellular and Wi-Fi performance and gives a variety of different measurement options. You should make sure you’re measuring in dBm because that’s the only really honest true way to compare signal.
The app measures signal constantly but it can take up to 10 seconds to detect a change. You will probably be able to see a big difference between signal strength inside and outside.
Here you can see that signal levels are -107dBm which is really on the low side. Time for a signal booster!
For people who really want to be obsessive, there’s a home screen widget that will also show signal strength.
Personally, I do this stuff for a living and even I am not that into watching the numbers go up and down. But it’s fun to play with for a while.
Measuring Your Signal On iPhone
Apple really doesn’t want you to know what your phone’s signal strength is. They don’t allow true signal metering apps on the app store so you would have to jailbreak your phone to find a signal meter app. Most people will not do this and I don’t blame them. There is another way.
Dialing *3001#12345#* on your iPhone will put it into “field test mode.”
This will show you all sorts of weird information about your phone’s reception. Luckily you don’t need to know any of it. The only thing you care about is that it shows the signal strength in dBm instead of bars.
-114dBm? Eeek! Time for a signal booster!
To get out of field test mode, press the home button. Just like Android, the measurements are in real time but it can take up to 10 seconds for the numbers to change.
Using The Signal Meter To Plan Your Installation
If you’re planning to install an antenna on your roof, you can use the signal meter app to check the signal levels in different areas to make sure you’re putting the antenna in the right place. Just make sure you pay attention to where you’re standing and don’t look at your phone too much. If you fall off the roof, no one wins, trust me.
Choose a part of your roof where the signal is as strong as possible and try to plan for a separation of at least 15 feet between the cell booster and the outdoor antenna. In some cases such as the Fusion4Home booster, you won’t get maximum power unless you put 45 feet between booster and antenna. If you have less than that the booster will automatically cut power to avoid flooding the entire cell system with harmful feedback.
With the right tools in hand, a cellular signal booster can be the best investment you’ll make in home or office electronics. Think about how many times a day you use your cell phone. Whether you’re talking, streaming, texting, emailing, or something else, this is the one device you can’t live without. Making sure it has a good strong signal will give you a better experience and possibly even increase your battery life. Cell boosters can be costly, but if you choose wisely, you’ll get years of service from a booster that will make your phone work better.
By Stuart Sweet
Stuart Sweet is a Certified SureCall Commercial Cell Booster Installer and RF expert. He is also the managing editor of The Solid Signal Blog, the leading source for news and information on satellite, cellular, over-the-air and streaming devices, as well as being Director of Product and Market Integration for SolidSignal.com, which offers many of the products Stuart blogs about.