Best Cell Phone Signal Boosters

AT&T Cell Booster

• AT&T's Cell Booster is actually a femtocell that broadcasts an LTE signal within your home, allowing your phone to connect to it via LTE and then use your internet connection to reach AT&T Mobility Servers.
• Some issues users face with the Cell Booster include connection issues, maintenance, and AT&T Support being clueless on how the device works.

Verizon MiFi 8800L Antenna Options

• AntennaGear M39: Offers an 8-10dB gain, needs about 35' of cable to connect.
• Haven Technologies Brick: Provides a 4.5dB gain, requires about 20' of cable to connect.

Outside Antenna for Poor Cell Signal

• CEL-FI GO G41: Claims to be "5G ready," which might be misleading.
• WiBoost Extenders: Now clearly state support for boosting 5G.

Cell Boosting Options

• WeBoost: A popular choice for cell boosting, compared to more expensive options like CelFi.

Improving Office Building Signal

• Using an external antenna and booster setup like Waveform 4x4 Mimo may provide better results than a traditional booster.
• Consider mounting a small antenna outside the office window for improved signal reception.

Other Considerations

• Boosters may not significantly improve data speeds, especially for specific carrier bands.
• Boosters are more helpful for phone calls rather than data in certain scenarios.

Recommendations

• If outdoor mounting is not feasible, consider carrier support for WiFi calling/texting as an alternative solution in areas with poor signal.

For more detailed information, you can refer to the guides linked in the comments.