So, you installed your signal booster-expecting full bars and crystal-clear calls-but things aren't quite going as planned. Don't worry, you're not alone. Cell phone boosters are powerful tools, but like any tech, they sometimes need a little fine-tuning to perform their best.
This guide walks you through the most common booster issues-oscillation and overload-and how to fix them. We'll also share tips to improve performance, maximize your coverage, and get your booster back on track. Whether you're dealing with flashing lights on your amplifier or dropped calls in your "boosted" zone, we've got the practical steps you need to troubleshoot and optimize your setup. Let's dive in and get your signal strong again.
What Are the Most Common Reasons for a Cell Phone Booster Not Working?
While there are many different issues that can arise when boosting cell signal, most fall into one of two buckets: oscillation and overload. We'll cover both of these below and discuss the steps on how to fix each.
If your problem does not fall into either of these buckets, then contact us and our team of signal experts can talk through your situation and recommend ways to remedy it.
Oscillation
Oscillation occurs when the boosted signal that is being broadcast from the inside antenna(s) reaches the outside antenna and causes a feedback loop, similar to a high-pitched sound you hear if you take a microphone too close to an amplified speaker.
The signal booster amplifier will try to mitigate this issue by reducing the boosting power on the band that is causing the oscillation, which shrinks the coverage area so that it doesn't get back to the outside antenna.
This works a lot of the time, and because it does it automatically, you typically would not notice that it even happened. If you're seeing warning indicators on the amplifier that it is experiencing oscillation, then that means that the amplifier has tried to fix the problem and has reached its limitations, so we need to do other things to fix the problem.
One other thing to note: If the carriers that you need to boost all have roughly the same outside signal strength, then having the amplifier adjust the boosting power to fix oscillation is a good solution. If one carrier is strong and others are weak, then the strong carrier is going to have a much larger coverage area inside of the building, but the amplifier will reduce all boosting by the same amount, and shrink the weak carrier signals to almost nothing while it's trying to fix the strong signal causing the large coverage area. In this case, we'll want to try and fix the problem in another way and let the amplifier work at full power.
Fixing Oscillation
The very first thing to check when dealing with oscillation is whether the directional antenna is pointed across the roof or away from the roof (if you're using an omni antenna, then this does not apply). If the directional antenna is pointed across the roof, then there is a high likelihood that it is picking up boosted signal radiating out, so you should move the antenna to the other side, so that it is facing away from the building.
Once you've confirmed that the outside antenna is facing away from the building, then the main way to fix oscillation is to move the antennas further apart. Typically this means moving the inside antenna further from the outside antenna, but if there is an opportunity to move the outside antenna further away, and potentially higher, while still receiving the same outside signal strength, then that is a good option.
When moving antennas, vertical separation is more important than horizontal, though a combination of both is good. We also recommend powering down the amplifier before moving the antennas. Once the antennas are in the new positions, power up the amplifier and see if you're still experiencing oscillation. Keep moving the antennas if so.
If you've moved the antennas as much as possible and are still experiencing oscillation, one last thing to try is to introduce shielding for the outside antenna. If the antenna is outside on the roof, then moving it so that an object, like the chimney or air conditioning unit, is between the antenna on the roof and the rest of the building. If the outside antenna is installed inside, then placing metal, like foil or a metal filing cabinet, behind the antenna to block the boosted signal is an option as well.
Overload
Overload occurs when the outside signal from one or multiple carriers is very strong and is overloading the amplifier with too much cell signal. The amplifier will attempt to compensate for this by reducing the boosting power, but frequently the signal is too strong and the amplifier reaches its limitations before the problem is solved.
Fixing Overload
If you're using a yagi directional antenna for the outside, then the best way to mitigate overload is to change the direction of the outside antenna to receive less signal and allow the amplifier to work at full capacity to boost and distribute the signal.
Follow the instructions in the How to Aim a Yagi Directional Antenna guide to incrementally change the direction of the yagi antenna, and then check the amplifier for overload indicators and take signal readings inside with cell phones on each carrier you need to boost.
If it turns out that you're in an urban area and have multiple towers nearby that are overloading your antenna with strong signal from every direction, then the next best option is to use an attenuator, which is a component that sits on the antenna cable and cuts out a set amount of decibels from the signal coming in. An attenuator will cut back the cell signal across all carriers and bands, irrespective of if they are strong or weak, so it's not an ideal solution and should only be used if re-aiming the outside antenna does not help, as it may cause carriers with weak cell signal to have sub-par coverage and performance inside.
Finally, if re-aiming the outside antenna and cutting back the existing cell signal with an attenuator does not provide you with adequate coverage, the last option is to move to a more advanced amplifier that can handle a much stronger outside signal and scale its boosting power significantly down to compensate for the strong existing signal.
Additional Tips to Improve Performance
While most standard signal booster installations should provide you with sufficient coverage for quality voice calls and fast data, if you're looking to tweak your system to provide even more performance, here are some things that you can do:
- Reduce cable lengths: If the cables that you received with your system are longer than you really need, then purchasing a shorter cable will reduce the amount of signal loss and increase the amount of coverage that your system will be able to provide. Also, be sure that your excess cable is NOT coiled, but rather laid out in a back-and-forth pattern, as coils can cause interference.
- Upgrade to a lower-loss cable: In addition to shortening cable lengths, you can upgrade your cable to a lower-loss version (more shielded), so your system has more signal to work with and provide more coverage inside.
- Add more antennas: If you're using one inside antenna, and have a medium to strong outside signal along with a powerful amplifier, then you may have excess boosting capacity that is not being used by the single antenna. Adding another antenna can take advantage of this excess capacity and increase your total inside coverage area. You'll need to add additional cable and a splitter to add the second antenna to the system.
- Upgrade your antennas: We offer higher-performance antennas that can replace the existing antennas that come with your signal booster system, for more coverage and a better-looking installation.
- Increase the separation between your antennas: Amplifiers automatically reduce their boosting power if there is any oscillation (feedback) from the inside antenna(s) to the outside antenna. If your amplifier shows any indicator lights or readings that there is oscillation and it's working at reduced capacity, then increase the distance between antennas to allow the amp to work at full boosting power.