FAQ: Weak Cell Signal After Installing Signal Booster

Spread the love

After installing my cell phone booster I still have a weak cell signal. How do I fix this?

When installing a signal booster there are a few hiccups you can encounter and there are some simple ways to diagnose and resolve these issues. In this post we will focus on antenna separation and cable loss; two things that can cause a weak cell signal after installing your signal booster.


I have weak cell signals unless I’m right by the inside antenna.

Generally, the cell phone booster’s total coverage area is based on the strength of the outside signal. In other words, the better reception you have outside the better your cell signal will be further from the inside antenna. Two things you can do to improve the coverage area are:

  1. If you have an outside signal stronger than -90 dB (roughly 2 bars), you can expand your coverage area using our CM-WS-2 splitter, which would allow you to have two internal antennas. If you do choose to install the splitter, be sure to keep the cable runs off of the splitter short so as to cut down on cable loss. Additionally, we do not suggest adding antennas to the Flare, Flare 3.0, or Fusion4Home boosters.
  2. Where you place the outside antenna could dramatically change the signal you receive from the inside antenna. To find the best place to mount your outside antenna, use an RF signal meter or phone application to test the strength of the available signal at different spots around the building. Here is how you can use your phone to test cell signal strength. If you have a very weak cell signal outside of the building, you may need to look into alternatives to a signal booster.
  3. When you choose your inside antenna, it’s important to choose the right inside antenna for your home.  Typically, right angle antennas (available with Fusion4Home) will cover small spaces of one to two rooms whereas an indoor panel antenna, indoor dome antenna, or ultra thin indoor antenna will cover medium size homes with an open floor-plan.
  4. If you have enough room for the required separation, you may want to consider upgrading to a higher-power signal booster kit.


How much do I need to separate the outside and inside antennas?

Proper antenna separation is essential in order to prevent signal oscillation, also called feedback. We need to prevent this because it can cause interference with the cell tower and, ultimately, will reduce the coverage area your signal booster will deliver.

Separation is measured in a straight line from the exterior antenna to the closest interior antenna. There are a few different factors that will impact the amount of separation that you will need between the antennas.

  • It’s important to mention that the stronger the outdoor cell signal, the more separation is required. On the other hand, a more weak cell signal outside means less separation may be necessary.
  • The more material and higher density of the materials between the inside and outside antennas can mean less separation will be needed. On the other hand, you will need more separation if there is only one wall of thin wood and insulation.
  • The more gain a booster has, the larger the coverage area and, in turn, the more separation you will need.

Based on the amount of booster gain, measured in decibels (dB), we recommend you have the following amount of separation between the inside and outside antennas for your signal booster system.



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


My signal booster system can’t get enough separation.

Keeping in mind that the recommended antenna separation can be vertical, horizontal or a combination of both, if you still cannot get enough separation there are a few workarounds you can try: 

  • Does your booster have DIP Switches or Dials? If it does, you can manually adjust the gain of the booster. Based on the light sequences on your booster, you can turn down the gain levels for each of the five bands to lessen the amount of required separation. We suggest you don’t turn the gain down more than 50% on any one of the dials or DIP switch groups as this could completely shut down the signal for that band.
  • Using an omni-directional antenna? Try using a Yagi-directional antenna and pointing the antenna toward a cell tower in the opposite direction of your inside antenna.
  • Get reflective material, like metal, between your antennas. Aluminum is our typical suggestion as it is highly reflective of radio frequency (RF) signals and can eliminate the feedback or oscillation by reflecting the gain away from each of the antennas.

For other technical questions, support requests, or any other needs, contact our US-Based technical support team anytime at 1-866-365-6283. Otherwise, get everything you need to know about cell phone signal boosters in this Ultimate Guide to Signal Boosters.

More Helpful Info About Signal Boosters:

What Blocks a Cell Signal?
What Blocks a Cell Signal?
How To Test a Cell Signal?
How To Test a Cell Signal?
Guide to Mobile Signal Boosters
Guide to Mobile Signal Boosters

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.