By the term "range" of a Wi-Fi network we refer to the strength of the signal. Most people think about it router determines the signal strength in a Wi-Fi network. But it's not exactly like that.
The range of the router does matter, but it can be improved by adding more points access (access points). We usually do not use additional access points at home, as a standard router is enough to share WiFi in all our spaces. 
Conversely, a standard router is not enough for businesses that have more floors or more space. In this case additional wireless access points must be added.
Wireless access points form a wireless local area network (WLAN). The amplitude of such a network and the amplitude of the router is determined by:
- The location of the access point and how far it is from the devices trying to connect to it.
- Objects between the access point and a device. A wooden door will not be a big problem, but a metal one can even block the signal.
- The 802.11 protocol you are using. Apple, for example, uses 802.11n, which is faster than the 802.11 protocol.
Wi-Fi Frequencies and channels
Another factor to consider when setting up a WiFi network is which channel it uses. A correct channel can give you much faster speeds while a wrong one can limit them.
Routers and access points transmit signals at a specific frequency. The frequencies commonly used by 802.11 protocols are at 5GHz, and at 2,4 GHz. Higher frequencies are used in other 802.11 protocols such as e.g. 802.11ad which can be used for frequencies up to 60GHz.
Most routers use the 802.11 protocol for this and we meet the frequencies of 2.4GHz and 5GHz more often.
At 2,4 GHz, there are about fourteen channels. Of these fourteen channels, 1, 6 and 11 are the only ones that do not overlap.
At 5GHz, there are 24 non-overlapping channels, however this frequency can be blocked by various objects in a house, such as an indoor plant.
Overlapping channels are channels that share the spectrum of frequencies and thus interact with each other. Non-overlapping channels are spaced apart and do not need to share spectrum, which makes them faster.
Device range
Of course, the router and access points are only one part of WiFi. The other part is the device that connects to the router. Each device connected to a WiFi network does so through its own built-in network card. This card has a certain operating range and outside of it can not detect any WiFi network signal. Most devices can scan Wi-Fi connections within a 300-meter radius.
Routers
A router that supports different 802.11 protocols (eg 802.11n) allows you to download much faster. So before buying a router it would be good to ask which 802.11 protocol it supports. The specific ones information συμπεριλαμβάνονται στις προδιαγραφές του router και μπορούν να βρεθούν στη ιστοσελίδα του κάθε product.
