What is Oscillation?

If you’ve spent any amount of time investigating cell phone signal boosters, you’ve come across the word oscillation. In this post, I will try to answer the question: “What is oscillation?” and explain why it matters in the world of cell phone signal boosters.

Wikipedia defines oscillation as:

Oscillation is the repetitive variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states.

That definition is as useful as those little “do not remove” tags on mattresses. Basically, an oscillation is anything that repeats itself over and over. In my opinion, oscillation is the wrong word to apply to the problem that its talking about.

What’s the Problem?

I remember many, many years ago when my parents took me to my first concert ever; the “Beach Boys!” It was awesome! The cassette tapes my dad forced us to listen to in the car I was now hearing live! I LOVED it.

Before the concert, the emcee got up on stage to do a little giveaway. Whenever he walked too close to the stage speakers, the stadium would erupt with a high-pitched screech. Walking away from the speakers would make the screeching stop again. The emcee kept forgetting about the feedback and kept walking too close to the speakers. It was super annoying!

The rest of the world calls this high-pitched screeching  feedback. When the microphone would pick up the amplified signal from the speakers, which was the amplified signal from the microphone, which was the amplified signal from the microphone…

Basically when something is amplified multiple times, it quickly becomes amplified out of control and quickly becomes unmanageable. The small signal from the microphones is amplified multiple times until it is too large to amplify and it sounds terrible.

Signal Boosters and Oscillation

The same thing can happen with cell phone signal boosters. When the outside antenna and the inside antenna overlap coverage, there exists the potential that the signal booster could pick up the amplified signal and re-amplify that signal repeatedly.

What does that mean for cell phone signal boosters? Well, just like the feedback that occurs between the microphone and the speakers in my earlier example, the same type of problem occurs with RF and the cell phone signal boosters.

When a cell phone signal booster receives a signal on the outside antenna that it has already amplified, it will re-amplify that signal. This will create a big feedback loop and inject an RF version of that audio screech into the RF spectrum. This big blast of signal can cause quite a few problems. When that big blast of RF makes its way back to the cell phone towers it can actually overload and take down the cell phone towers.

Avoiding Oscillation

At the Beach Boys concert, walking away from the speakers caused the feedback to stop. Likewise, keeping the outside and inside antennas away from each other is how to avoid oscillation from cell phone signal boosters. When cell phone signal boosters first hit the market, the manufacturers relied on people to properly install their signal boosters to make sure that this oscillation (or feedback) didn’t do damage to the cell phone towers.

Naturally, the general public kept installing these cell phone signal boosters improperly and caused problems for the cell phone companies. To prevent problems, the signal booster manufacturers created a way to keep these boosters from acting bad when installed improperly.

So, they invented an oscillation detection algorithm to detect when these amplifiers were oscillating. These amplifiers would sense when they were in an oscillation and shut themselves down. Win/win right?

Politics

Not exactly. The cell phone companies launched a huge effort to shut down cell phone signal boosters because these devices infringed on their frequencies. The major players in the signal booster industry launched a huge counter-effort to persuade the FCC to, in effect, not “throw the baby out with the bath water.” There’s my nod to Joe Banos, who helped lead the charge as Wilson Electronics COO at the time.

Things got ugly. Even Senators got involved in the fight. A special tip o’ the hat to Utah’s Senator Orrin Hatch who allowed his office to be used to tell all parties to play nice. Then, our big brother the FCC stepped in to save everyone. The FCC mandated that cell phone signal boosters adhere to certain design characteristics, which all boosters currently selling on the market must follow–if they’re FCC approved.

Anyways, if you have any more questions about cell phone signal boosters, I’m always happy to answer them. Just drop me an email to [email protected] and I will be happy to answer them for you.

As always, if you are ready to make a cell phone signal booster purchase, I am more than happy to sell them to you here in my online store. Thanks for stopping by!

– Rob

What Frequency Does My Cell Phone Use?

I have answered many emails asking the same basic question, “Will booster X work with my cell phone provider Y?” Or, “What Frequency does my cell phone use?” In this post I’ll try to help you figure out what cell phone boosters will work with which carriers and how you’ll be able to figure it out on your own.

In order to understand this concept a little better, I might need to go back in time a little bit.

What is a radio frequency anyway?

The year was 1865.

The Civil War was just coming to a close. President Lincoln was visiting Ford’s Theater for the last time. Meanwhile, somewhere in England, in the dark recesses of the Scottish mathematician James Clerk Maxwell’s brain, the theory of electromagnetism was being conceived. Maxwell had mathematically proved that electricity, magnetism and light were all manifestations of the same phenomenon.

In a nutshell, he had demonstrated that electrical and magnetic fields travel, intertwined through space at the speed of light. Eventually, his findings would go on to prove the existence of radio waves, or radio frequencies (RF).

Light waves and radio waves are basically the same thing. They are electric fields moving in conjunction with magnetic fields. So, light waves move at a wavelength of 380-450 nanometers (that’s REALLY short) and the longest radio waves have a wavelength of about 100,000 kilometers (super long).

Big Brother To The Rescue

So people started experimenting with radio waves. Marconi was transmitting sparks across the Atlantic Ocean and people were having a free-for-all with their radio frequencies. So, in stepped the great overseer, our big brother, the federal government to protect us all from the harm that we would undoubtedly cause ourselves by not having someone to tell us what to do with this plethora of available, free radio frequency.

Thus, in 1934 the FCC was born to manage radio frequencies in the US and eventually, somehow, manage to make themselves in charge of our Internet freedom. The FCC took the available spectrum and organized it into different blocks. Here is a pretty good diagram of how our current radio spectrum is divided in the US. Download your own copy of the US frequency allocations chart to print out and hang on your wall here.

What does this have to do with ‘What frequency does my cell phone use’?

Valid question. Right there in that picture, the middle of the fifth band from the top are a few little sections called “Fixed Mobile.” That, my friends, is where cell phones live.

Here are a few fun facts that I found on Wireless Advisor.com‘s website:

Did you know…

The United States is divided into 734 Cellular markets (850 MHz), 493 PCS markets (1900 MHz), 734 AWS markets (1.7/2.1 GHz) and 734 700 MHz markets?

That there are more than 150 wireless and cellular phone service companies in the U.S.?

So, there’s 150 wireless and cell phone companies in the US?!? What?!? I’ve only ever heard of 4 or 5 of them. Verizon, Sprint, AT&T, T-Mobile and US Cellular, right? With all of these 150 different carriers, it could get really difficult to find my provider’s frequency, right? But, the good news is because they all use the same few cell phone bands, signal boosters can be designed to work on all of them at once.

Like the quote above states, there are four major cell phone frequency bands in the United States.

• 700 MHz
• Cellular (850 MHz)
• PCS (1900 MHz)
• AWS (1.7/2.1 GHz)

When choosing a cell phone signal booster, if you pick any of the boosters that work on 3G and 4G, you can be sure that it will work on any of the cell phone providers in the US. There are still a few boosters in production that only work to enhance voice, text and 3G data signals. Those ones will only work on the Cellular and the PCS bands listed above. So, to be safe, I would personally only purchase a booster that will work on all 4 bands.

So, What Frequency Does My Cell Phone Use?

Getting back to the point, if you are unsure of whether the booster that you are considering will work on all of the cell phone bands that your carrier uses, you can always consult the internet to get a second opinion.

I found that the Wireless Advisor’s site usually gives pretty accurate results. I just punch my zip code into the webpage and hit submit. And it spits back all of the wireless carriers in my area and what frequencies they use in my area. Then you can check the datasheets of the cell phone booster that you are thinking about and make sure that they are included.

Or, if that’s too much trouble, you could just as easily drop me an email with your question. I’m always happy to respond. My email is [email protected]. Or if you have any questions about any of the products that we sell in our online store, I’m always happy to help!

Thanks for stopping by!

– Rob

WeBoost Drive 4G-X vs SureCall Fusion2Go 2.0

A while ago, I had the opportunity to compare the WeBoost Drive 4G-X vs SureCall Fusion2Go 2.0. We tested the boosters at a remote mountain location and the results really surprised me. Before I get into the, as “Nacho Libre” would say, ‘nitty gritty’ let’s get a little background on the vehicle cell phone booster industry.

Why a Vehicle Cell Phone Signal Booster?

I remember many, many years ago when I was a young broadcast engineer. I was in charge of the upkeep and maintenance on 5 radio stations and 2 television repeater sites. It was my first full-time job out of college, and I barely knew what I was doing. That’s when I learned that college doesn’t give a man skills. It just gives him a little bit of knowledge. The skills come with work, practice and failure. Lots and lots of failure.

One particular time of my great failure is the following story that I am about to share. I once had a transmitter go down. Of course, it was in the middle of the winter, at the most remote location we had. I wasn’t prepared for this outage at all. Surely, I was awoken from a deep, deep slumber where I was probably dreaming about defeating ninjas, or slaying dragons or something else extremely manly. I staggered to my truck and began the trek to Cedar City, the location that housed our “Snow Cat” that I’d have to use to make it to the transmitter site.

It was cold. I hate the cold. As I write this, I am sitting in on my couch in my living room, 10 feet from the roaring fireplace, wearing my Carhartt coat and praying for a speedy end to the winter season. I am warm blooded. I’d take the desert and its blistering, scorching sun ANY DAY over the smallest skiff of snow. Because I HATE the cold. I had been to the location that housed the snow cat before, but never at night. And never in the cold, cold snowy night.

Cell Phones… Can You Ever Count On Them?

In those days, cell phones were not what they are now. Cell phone navigation was just a passing thought. My personal phone was an iPhone, but Apple Maps was terrible back then. It sucked. It had no maps of the area I was headed. The only thing worse than my pathetic, work-issued Kyocera phone was the terrible service that our radio station had traded for advertising.

In those days, cell phone data as we know it now was NOTHING like it is today. I plugged the address where the snow cat was parked into my iPhone and I was on my way. At some point during the hour drive, I lost cell phone service. I was left with an un-downloaded map and after driving around in circles for an hour, wasn’t able to find the darn snow cat. I drove back to where I had service, waited for about 20 minutes while my iPhone (that also had the terrible service) downloaded the rest of the map. It was a disaster.

When I finally found the snow cat, it had snowed so much that I no longer recognized the way to get to the transmitter site. It was a disaster. We ended up being off the air for over a day. It was terrible. Did I mention that it was a disaster?

Enter Vehicle Cell Phone Signal Boosters

In the world of Little Texas and “What Might Have Been” things would have been different. If only a few years later, the radio station might have traded out a cell phone signal booster for my engineering truck (they never bought anything, it was always trade). Then I would have been able to find the stupid snow cat before everything was snowed over beyond my recognition.

My cell phone signal booster would have allowed me to get that map downloaded. I would have kept my cell phone service and I would have been a hero to the teeny boppers waiting to hear Sean Paul‘s terrible music while getting ready for school in the morning.

In all honesty, vehicle cell phone signal boosters are absolutely amazing. They work great and they can keep you connected in those troublesome fringe areas where service tends to be as reliable as the work for Glynn Wolfe‘s wedding planner.

The Comparison

When I worked as an engineer at Wilson Electronics (now WeBoost) I was pretty skilled at fixing the “Mini” vehicle signal booster. I knew that thing backwards and forwards. Inside and out. It was a great cell phone signal booster for vehicles. That was, of course well before the days of 4G. Now things have changed some, and I was a little unsure of how the flagship SureCall vehicle cell phone booster would stand up to the WeBoost version of the same thing. So I decided to get out my lab coat (you can always trust a guy in a lab coat) and put it to a test.

I installed both of the cell phone signal boosters, in parallel, in a friend’s vehicle. We drove that thing up to the beauty of the Cedar mountains (this time without snow, and in the daylight) and tested them out side by side.

Because cell phone bars readouts are more than a little misleading, I would test the boosters by comparing their actual performance on how they did with helping me make a phone call. I would first turn on one of the boosters, make a test call and then try the other one. Both boosters were installed according to manufacturer’s specifications and tested making a cell phone call to the love of my life. Besides, she had nothing better to do than sit around and wait for my phone calls, right?

The Results

I had a friend video record the results of our tests. I will let the video mostly speak for itself, but I will tell you that the SureCall signal booster FAR outperformed the WeBoost signal booster in my field test.

The first call that I made to my wife with the SureCall signal booster went through immediately. Much faster than I expected, actually. I then tried to make the same call with the WeBoost signal booster, and the first call didn’t go through. I made the call again and I found that the call was only working in one direction. My wife couldn’t hear me, but I could hear her. Strange. And surprising for me because having been on the team making developments to the Wilson Electronics cell phone signal boosters, I thought that they would have definitely been able to outperform the SureCall signal booster.

Conclusions

So, If you are looking for a reliable vehicle cell phone signal booster that will work on the outskirts of a remote area, I would definitely recommend the SureCall Fusion2Go 2.0 cell phone signal booster. In my tests, I found that it easily outperformed the WeBoost Drive 4G-X booster. Which was surprising for me, because I totally didn’t expect it to do better.

If you are looking for the vehicle cell phone signal booster that I tested in this video, you can find it here in my store.

As always, if you have any questions or need help in figuring out which cell phone signal booster is right for your situation, please feel free to drop me an email to [email protected]. I love this stuff and I’m always happy to help out!

Thanks for stopping by!

-Rob

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.

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.

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.

Decibels

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.

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: [email protected]

Thanks for stopping by!

-Rob