The term "bandwidth" of a Wi-Fi network refers to signal strength. Most think the router determines the signal strength on a Wi-Fi network. But this is not exactly the case.
The range of the router is important, but it can be improved by adding additional access points (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 one wireless local area network (WLAN). The range of such a network, as well as the range 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.
In the 5GHz frequency, there are 24 non-overlapping channels, however this frequency can be blocked by the various objects present in a house, such as a plant indoor space.
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, o router και τα σημεία πρόσβασης είναι μόνο το ένα μέρος του WiFi. Το άλλο μέρος είναι η συσκευή που συνδέεται με το router. Κάθε συσκευή που συνδέεται σε ένα δίκτυο WiFi το κάνει μέσω μιας δικής της, ενσωματωμένης κάρτας δικτύου. Η κάρτα αυτή έχει μια ορισμένη περιοχή λειτουργίας και έξω από αυτή δεν μπορεί να ανιχνεύσει κάποιο σήμα δικτύου WiFi. Οι περισσότερες συσκευές μπορούν να σαρώσουν connections Wi-Fi within a radius of 300 meters.
Routers
A router that supports different 802.11 protocols (eg 802.11n) allows you to download much faster. So before you buy a router it would be good to ask which 802.11 protocol it supports. The specific information is included in the specifications of the router and can be found on the website of each product.
