When is a Yagi Antenna Warrented against Omni-Directional Antenna

One question we often get from new customers is what is a Yagi antenna and if they must get a Yagi antenna instead of an omnidirectional antenna? Simply put, a Yagi antenna is nothing more a the old school TV antenna, but configured for cell phone frequencies. Similar to TV antenna, when installing this type of antenna , it is necessary that you locate the cell phone tower by rotating the antenna 45° at a time and pick the location that shows the most bars on your cell phone.
The deciding factor in determining the type of antenna boils down to the tower location and how many bars your cell phone can pick inside the building. In majority of locations all the major cell phone carriers share a common tower and a Yagi antenna works fine and able to pick all carriers.

a) Is your OUTSIDE cell phone reception very weak, less then 2 bars?
b) You think you can install a TV antenna or have installed a TV antenna in the past?

Note: Yagi antenna can be not a very good choice in some locations where the signal is too powerful and due to its high sensitivity in capturing and broadcasting signal, it can create a feedback loop with the indoor antenna and introduce unnecessary noise.

A Omnidirectional antenna is recommended if your OUTSIDE cell phone reception is more then 2+ bars?

Yagi antenna is an antenna designed in a pyramid like structure with multiple elements with increasing length, usually 5% increments that act as elements that makes the cell phone signal to funnel in and thereby increasing the signal strength.
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Omni-directional antenna

Omni-direction cell phone booster Vs Yagi cell phone booster