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Signal Booster's Flashing Red Light Cause or Reason and its Resolution.

Sep 06, 2016

What is the cause of a signal booster's flashing red light? Let us find out...


Fixing the Flashing Red Light on a SureCall Booster.

If there’s one issue that makes most SureCall booster users to call the technical helpline it’s the issue of the flashing red light. It’s actually easy to address. 

Why does it occur?

The flashing red light usually happens once the incoming signal is too strong for the booster. It is important to understand what “too strong” means. Before you do that, find a way of measuring the dBm (decibel-milliwatts) strength accurately of outside signal within area you are intending to place your outer antenna. dBm is used to measure cellular phone signal strength. You can actually test the dBm strength in three mains ways for area where you would like to put up the external antenna. 

Use your phone.

This is the least effective way of testing the dBm strength. As you use your phone, note that it is not checking the bars; put the Smartphone into test mode and check the dBm strength received in the phone.  

Mobile application .

This is also another way of checking the dBm strength. Of course, as you might have guessed there’re many mobile apps for doing this. One of this is the Network Signal Info for Android mobile devices.  

These two ways (your phone and mobile app) are problematic though; They will only work for the signal carrier and your mobile device only. 

RF Signal Meter.

Another way of checking the dBm strength is through a working RF signal meter. The meter is capable of reading the strength of the signal for each of the frequency block/range across RF spectrums. One of the dBm strengths you should be looking for as you seek to find the right place to have the external antenna fixed should be within the -90 (negative 90) mark and -70 (negative 70) dBm. 

Once flashing red light starts happening on your SureCall booster you can fix it in a number of ways.

Change external antenna location.

One of the ways of doing this is simply changing the external antenna’s location. If you have diverse cell towers within the area where you live you need to know your own specific carrier’s cell tower. Use to find the towers within where you live that support the network of the carrier you’re using. After finding that out, decide on the best antenna you need to use for your outdoors. 

For a tower that is a bit close to your home or building there will be a very strong signal entering the booster resulting in flashing of the red lights. This means there’s overpowering of the booster that will soon trigger the unit to shut off. A Yagi directional antenna and pointing it towards the tower might be the normal thing to do, but the high gain type of antenna will result in an overpowering of the booster system. 

Deal with this by changing the Yagi antenna’s direction. Turn it another way but not directly towards the cellular tower. In the process, the signal entering the booster will be reduced and the red light flashing will stop. 

Cellular towers have a wide radiation pattern and an Omni-directional antenna might be a good idea in contrast with a Yagi directional antenna. Omni-directional antennas have a gain of between three and four decibels and thus some of the lowest gaining antennas; it can aid you in ensuring the signal amount entering the booster is not overpowering. 

Inline attenuator.

You can also deal with flashing red light by getting an inline attenuator. It connects with the outer part of the SureCall booster with the cable going to the antenna. The inline attenuator works by ensuring the signal doesn’t turn out to be too overpowering as it enters the booster. It perfectly eliminates a chunk of the signal entering the booster. 

SureCall Video Transcript:

Hello, here's another episode of "Two-Minute Troubleshooting" by SureCall. In this episode, we're going to be addressing one of the most common reasons for people to call into our helpline, and also one of the easiest ones to address and also to fix: The flashing red light.

The red flashing light occurs because the incoming signal to the booster is too strong. Well, how much is too strong? Before we get into that, we have to figure out an accurate way to measure the decibel strength of outside signal in an area that you plan on putting the outside antenna. There're three ways that you can actually test the decibel strength in area where you think you would like to place your external antenna. Let us go in order from the least effective to the most effective way of doing that.

The first way is by utilizing your phone. And by using your phone, I'm not talking about checking your bars. Put your phone into test mode to check the dB strength that your phone is receiving.

Another way is through a mobile app. There're many. One that we have used is for the Android phone and it is called Network Signal Info. The problem with these first two ways of checking your DBM strength is that they only work for your device and for your carrier.

The third way is by using a tool called an RF signal meter. These meters can read signal strength for every frequency range or block on the RF spectrum. The DBM strength you're looking for, when you're looking to find out where to place your outside antenna is anywhere between negative 90 and negative 70 DB.

If you do find that the red lights are flashing on your booster, there're couple ways you can fix that.

The first one is by changing the location of your outside antenna. Let us say, for instance, that this is the area that you live in, and all of these red pins are the cell towers in your area. Now you live here. Now as you can see, there're lots of carrier towers in the area but which one is for your specific carrier? You can go to to find out which towers in the area support your carrier's network. Once you find out that information, you can decide which antenna is best for the outdoor donor antenna.

For instance, your carrier's tower is here. Now that is a pretty close to the building or to the house. It is quite possible that there will be too much signal going into the booster and it will result in the red lights flashing which signifies the booster is overpowering and will shut off. Now if you have a Yagi directional antenna, it would make sense to try to point that antenna to this tower. However, pointing that high gain antenna right toward the tower will overpower the system.

There are some ways to get around this. The first thing you might try to do if you are getting the red flashing lights on your booster is try to change the direction of the Yagi antenna by pointing the directional antenna away from the cell phone tower. It is quite possible that you will reduce the amount of signal coming into the booster and that will get rid of the red flashing lights. Cellphone towers usually have a large radiation pattern so it is possible that you need an omnidirectional antenna for your donor instead of the Yagi directional. The omnidirectional antenna is only 3 - 4 DB of gain so it is a lower gain antenna. This may help with the amount of signal getting into the booster.

Another way that you can make this red flashing light go away is by purchasing an inline attenuator and this will actually connect from outside part of the booster into the cable that goes to the antenna. What it does is it keeps the signal from getting too strong going into the booster. It actually eliminates some of the signal coming in.

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  • I don’t own a cell phone booster but I think it’s good that there is a technical helpline for those times when something happens and you’re not sure how to correct it. When you consider how a cell phone booster works (boosting the existing signal), it makes sense that you might have to adjust the booster so the signal isn’t too strong. I guess that’s such a thing.

    Marek Wiśniewski on
  • Mort, you ask: Now, can you tell me why I can never get a good cell phone signal in Best Buy? Is it because all the other electronics are interfering with the signal? It really is aggravating. I was there and tried price checking a computer only for my phone to spin its figurative wheels. Okay, here’s what I know. Your phone gets slow or drops calls when a cell signal is weak and interrupted (respectively). This can be due to the cell tower (which sends the signal to your phone) is far away, or it’s having problem getting through the materials that make up the Best Buy store. Either factor can do a number on you getting cell phone signals. Remember this too: If the signal in Best Buy is weak, everyone in the store with cell phones is competing for the precious signal, which weakens it further.

    Adam Jackson on
  • Nice explanation of the different lights on cell phone boosters. Now, can you tell me why I can never get a good cell phone signal in Best Buy? Is it because all the other electronics are interfering with the signal? It is so aggravating, especially when I want to do a price check with a competitor.

    Mortimer Duncan III on
  • So say I have a Weboost 460020 cell phone booster at home and the lights start flashing. What do I do when I see my Weboost blinking red? What happens when I see my Weboost blinking orange and green? Do I go, “Puny Weboost 460020 make Hulk angry! Hulk smash!” No, thanks to you guys, I know what these lights mean and how I can make sure my cell phone booster is working right.

    Steven Greene on
  • Glad there are ways to troubleshoot problems with your cell phone booster. These devices can do wonders for your cell phone such as increasing the quality of your reception and boosting data speed. Like any technology, there are things to make sure it’s working right. Thanks for posting this as I’m sure people with cell phone boosters appreciate it.

    Roderick Wilson on
  • Seems like a common situation for people who use the device. It’s good that this site has so many helpful videos. I know I would have called customer service when I could fix the problem myself. Who remembers the old days when you had a problem with technology and had to wait forever to get a solution-or worse yet-had to hire an expensive technician. I’m so glad there are ways to DIY now.

    Larry Stanford on

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