How to improve cell signals inside, when no signal outside?

If you barely have signal bars outside your home or office, a typical signal booster will not help because signal boosters amplify the little signal there is outside and broadcast it inside. However, a strong and powerful phone booster will work well in most situations with poor signal, but there're three scenarios in which signal boosters may not, or will definitely not work.

1. When an antenna can't be installed outside an office or home.
2. When a specific carrier's distant, weak cell signals are overpowered by stronger cell signals from a different carrier's cell tower which is closer.
3. When a carrier has no detectable cell signal, or a very, very, very weak signal in any location outside where exterior antenna can be mounted.

These situations are discussed in more detail below:

1. When an antenna can't be installed outside an office or home

A cell signal booster normally needs a tower (outside) antenna to enhance cellular signals. The booster uses the outside antenna to collect signals from the cell tower, and sends it along coaxial cable to the booster which amplifies the signal.

There are however some situations in which it may not be possible to install an antenna outside an office building or home. A Home Owner's Agreement (HOA) may for example not allow exterior antennas on homes, or an office lease may prohibit additions outside of a building.

In these circumstances, it may still be possible to use a cell signal booster to provide better phone reception.

If enough cell signal penetrates into any building, a cell booster system may still be installed and work effectively without an antenna being installed outside the building. Although a tower antenna is still needed, it is possible that the booster system may work when the tower antenna is installed next to a window inside.

Care should however be taken to ensure that there is enough separation distance between the inside and tower antenna.

This installation method will work if a call can be placed and not dropped next to the window where the cell signal is the strongest. If this is not the case, this installation method is likely not viable for the location.

There're signal boosters available that use a tower antenna that doesn't need to be mounted outside the building, but between a window and its screen.

2. Carrier signal overpowered

If there's cell tower belonging to another carrier between the building where reception is required and the tower belonging to the carrier that should be used, a signal overload from the other carrier may prevent a signal booster system from working properly.

If this is the case, the signal booster collects and amplifies cell signals from both towers. The stronger signal from the other carrier's closer tower would cause the booster to operate at less than its maximum capacity. This is because FCC regulations require that cell boosters detect the level of incoming signal available and adjust amplification automatically for the strength of the strongest signal.

The strong incoming signal from the closer tower will prevent the booster from amplifying the weaker signal from the required carrier tower further away sufficiently. This will result in the required carrier’s signal not being amplified enough. Therefore, you have have to contract services from a professional installer who will be able to resolve this with a channel filter.

3. No detectable, or very weak signal

Cell signal boosters work by amplifying existing signals. Booster won't work if there is no detectable signal available in a specific location.

To help determine if the cell signal is strong enough for a booster to work, check if there is a strong enough cell signal available to place a call and keep the connection without it dropping while outside the office or home. If this is the case, then a booster system should work to bring that available cell signal inside the building to enhance your indoor cell reception.

If there's not a strong enough cell signal available to place a call and keep the connection without it dropping while outside the office or home, a signal booster will probably not work.

Before accepting this however, let us look at the problem and possible solution in a bit more detail.

Signal booster operation.

Signal boosters take weak cell signals from outside and amplify these. The boosted signals are then spread inside vehicles or buildings to provide phones and other cellular devices with a solid connection. The signal booster also amplifies signals sent from the devices back to the cell tower to complete the loop.

Signal boosters cannot create cell signals and need an existing cell signal in order to work. If there's really no cell signal at a location, a signal booster has nothing to work with and can't enhance signal.

No bars showing on a phone does however not mean that there is no signal. In spite of a phone's service strength graphic showing no bars, there might still be a signal.

Signal boosters have receivers with high sensitivity and can detect much weaker signals than what a phone can. This means that even though a phone shows no bars, a signal booster may be still be able to collect faint signals and amplify these to enable a phone to connect. A signal meter may be used to detect signal strength most accurately from all carriers. A single carrier service strength can be detected by using a smartphone with active rate plan from a carrier and going into test mode to detect signal strength in "Decibels".

To recap, even a signal booster can't get service if there is no signal that can be detected.

How to determine if there is signal?

The bars on a phone are not reliable to determine the level of cell service available. The easiest way to accurately determine signal strength is to use the Field Test Mode of the phone. This is easy to do on both Android phones and iPhones.

If Field Test Mode on a phone shows a signal strength of -85 dBm or better, a signal booster can probably improve your signal, while a signal strength of -100 dBm or weaker means a cell booster will probably not help to enhance reception. If it shows a strength of between -85 dBm and -100 dBm it is difficult to predict if a booster will help.

How to connect a phone where there is no service?

Even if there's no cell signal detectable, one can be created using a Microcell as long as a broadband Internet access is available. Microcells, also called femtocells, use Internet connections to create a local cell signal that will cover between one and three rooms in a house.

Micro Cells are basically low-powered cellular base stations. When these're connected to a router, they use broadband Internet to create a signal source to provide cell phone coverage inside an office or home.

This option is however only available if broadband Internet connection is available.

A microcell is carrier-specific and will only work with cellular devices that use the specific carrier that supplied the device. Devices using a different cell carrier can't benefit from the improved cell service provided by the microcell, even when within range of the microcell.

To use microcell coverage, phones and other devices must be synced, or logged in, to the microcell. Any device that is not synced to the microcell will not benefit from its cellular signal.

If no signal outside for very large homes and buildings, we can provide commercial grade active distributed antenna system (DAS) solutions that work through Internet. Essentially, cell phone boosters that work through Internet are called Femtocells or Microcells. Please provide location details for bill of materials (BOM) and installation cost estimate.