Does the gateway need to have a repeater in an average sized house?

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The wireless signal range is great for a Wi-Fi access point with an internal antenna, but it doesn’t have the reach of a higher end access point with multiple external antennas. You’ll get the best range if you place the Smart Gateway on a flat surface in a centrally located, unobstructed location.

In a larger house you may need multiple Smart Gateways in different locations for full coverage.

It is designed for up to 4 cameras. If you will be using more than 4 cameras or range may be an issue, you would need either another SG130, or you could instead use a higher end access point with external antennas and set it to only use 2.4ghz wireless with a unique SSID.