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Causes of Weak Signal Even After Installing Cell Phone Booster

Nov 28, 2018

Causes of Weak Signal Even After Installing Cell Phone Booster

I have a weak cell phone signal after installing my signal booster. What can I do to fix the problem?

Following the installation of a signal booster, you're sure to encounter a few problems along the way. Luckily, most of these problems can be resolved by following a few simple tips. The trick is to properly diagnose the problem to determine the best solution. What to do if signal strength did not improve with weBoost / Wilson Electronics, SureCall, or Cel-Fi or any other brand signal booster kit?

If you're experiencing a weak cell phone signal after installing a booster kit, there are two main problems that should first be investigated before looking to other solutions. The first is antenna separation and the second is cable loss. Both of these can cause a poor cell phone signal even after installation of a cellular amplifier system.

FAQ # 1: My cell phone signal is weak unless I'm situated right next to an inside antenna.

In general terms, the total area covered following the installation of a signal booster is, in part, based on the outside signal and its strength. In other words, the stronger signal outside the building, the farther away you will be able to go from your inside antenna and still maintain a strong cell phone signal. In order to improve the total coverage area, there're several solutions you can try:

  1. If your outdoor signal strength is greater than -90 dB, or approximately two bars, this coverage area can be expanded by using, for example, an add-on surface mount antenna kit (this particular one's for 50 Ohm inside antenna port impedance kits which is majority of kits, but we also sell 75 Ohm versions for the few that require that different impedance). This unique antenna expansion kit allows the installation of two antennas indoors. Its uniqueness also lies in the fact that you don't need access to space on other side of the ceiling because it is "surface mount". This means that the cable comes out right against the same side of the ceiling where it is mounted - for easy installation, instead of having to pull it from other side of the ceiling making installation difficult. Should you choose to use a splitter, remember to keep the cables as short as possible to reduce the chance of cable loss. While a splitter can be used on the majority of signal boosters, we don't recommend using it on Fusion4Home, Flare 3.0, or Flare signal boosters.
  2. The position of the outdoor antenna can have a dramatic effect on the signal received from the indoor antenna. In order to determine the best position for the mounting of the outdoor antenna, use an application on your phone to measure signal strenth in decibels or an RF signal meter to measure signal strengths at various points outside the building. If, after using a phone app or an RF signal meter, you discover that you have a consistently weak cell phone signal outside your building, a signal booster may not be the right solution to the problem.
  3. There are many different types of indoor antennas to choose from, and your choice can have a dramatic impact on the strength of your signal indoors. Right angle antennas as used in Fusion4Home Whip Antenna kits are designed to cover small indoor areas, with a maximum of two rooms. In order to obtain maximum coverage for a home of medium size and with an open plan design, try an ultra-thin indoor antenna, an indoor dome antenna, or an indoor panel antenna.
  4. Should you have sufficient separation room, it could be a good option to upgrade to a signal kit of a higher power to solve the problem. For example, move up from Fusion4Home to Fusion 5s. Or upgrade from Fusion 5s to Fusion 5x. Or choose higher powered kit by moving from Fusion 5x to the highest powered commercial grade cell phone signal booster kit, Force 5.

FAQ #2: By what distance should indoor and outdoor antennas be separated?

Feedback, also known as signal oscillation, is an annoying yet common problem. Feedback can reduce the total coverage area delivered by a signal booster by causing interference between the antenna and the cell tower itself. By ensuring that antennas are separated by a sufficient distance, feedback can be avoided.

Separation between indoor and outdoor antennas is measured by way of a straight-line measurement between the indoor antenna and the outdoor antenna. The following factors will affect the total separation distance required between the indoor and outdoor antennas:

  • Separation distance is directly related to the strength of the outdoor signal. High-strength outdoor signals require greater separation distances, while poorer outdoor signals mean that a smaller distance is necessary.
  • Amount and density of the materials between antennas also has an effect on the separation distance required. Materials that block signalwill make it possible to have exterior and interior antennas closer to each other. For example, if two antennas are separated by one thin wooden wall with a small amount of insulation, a greater separation distance will be needed than if antennas were separated by a larger amount of more dense materials.
  • Booster gain is another factor to be considered. The greater the gain, the greater an area of coverage, and the greater the separation required between their two antennas. The following table shows the suggested minimum antenna separation between indoor and outdoor antennas based on the level of booster gain in decibels. As stated above, these figures may vary slightly on case-by-case basis depending upon variables and criteria stated above.

Interior and Exterior Antenna Separation Distance Chart:

The following table shows the minimum suggested distance required between outside and inside antennas to prevent oscillation or feedback which reduces effectiveness of any cell phone signal booster system. The range shown in the chart varies from 20dB Gain offered in a wide range of Consumer Signal Boosters that can be self-installed by end-users to 80dB Gain offered in Industrial Signal Boosters which must be installed by certified distributed antenna system installers.

BOOSTER GAIN (dB) SUGGESTED MINIMUM ANTENNA SEPARATION
20 dB 3 feet
30 dB 4 feet
40 dB 6 feet
45 dB 15 feet
55 dB 55 feet
65 dB 70 feet
68 dB 80 feet
70 dB 110 feet
80 dB 125 feet

 

FAQ # 3: What to do if I'm not able to achieve the reqd. separation in my signal booster system?

Remember that antenna separation can be horizontal, vertical, or a combination of both. With this in mind, if you still are not able to achieve the required amount of separation in your signal booster system, consider the following:

  • If your booster features a DIP dial or switch, try manually adjusting the booster gain for each of the five bands. While we don't suggest that you reduce the gain by more than 50% on any one of the bands as this could cause that band's signal to be completely shut down, you can try manually adjusting and reducing the gain to correspondingly reduce the separation needed.
  • If you're using an omnidirectional rooftop antenna, try using a Yagi or LPDA directional antenna, instead. Then point that Yagi antenna toward a cell tower in the opposite direction of your in-building antenna.
  • If all else fails, use a reflective material like aluminium or another type of metal to reflect RF signals between the two antennas, reducing or even eliminating oscillation and feedback by reflecting the gain away from both antennas. Many clients have had great success with this trick and using Faraday RF blocking Fabric, Patch, and Tape to deflect signals from exterior antenna to interior antenna which cause interference that we call oscillation.

If you require support or need answers to a technical matter, contact our US-based support desk at any time by phoning 1-855-846-2654. Otherwise, have a look through our Cell Phone Signal Booster Guide to find out (almost) everything you could need to know about cell phone signal boosters.


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  • Can anybody share their experiences after they’ve installed a booster? If it’s a matter of troubleshooting a minor problem, I don’t mind. If it’s a case of extra headaches, I don’t know if I want to buy a cell phone booster and have more headaches.

    Daryll Jefferson on
  • This doesn’t seem right. If you install a cell phone booster you shouldn’t have any problems with your cell phone signal. The only reason I thought a cell phone booster wouldn’t work would be if there was no cell phone signal to boost (or you happened to get a defective booster). It seems like there are some factors involved that might interfere. If that’s so, do you recommend getting the booster installed by a professional?

    Kevin Littleton on

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