3 ms·
AFAIK, there are not so much unlicensed frequency ranges that are available almost worldwide. 2.4 GHz was initially reserved to use in microwave ovens that can
by ungzd 9y ago
AFAIK, there are not so much unlicensed frequency ranges that are available almost worldwide. 2.4 GHz was initially reserved to use in microwave ovens that can cause interference in that range, then spread-spectrum technologies (such as used in wifi) that are not sensitive to noise from ovens became cheap so this frequency range became useful for that.
Other popular unlicensed range - 443 Mhz has much lesser bandwidth so it's popular for slower data transfers, i.e. in doorbells and temperature sensors. Also AFAIK it requires larger antennas because of longer wavelength.
5 GHz wifi is only recently started to become popular because, I think, there are some problems in implementing such high frequencies, or because it's more affected by walls and furniture.
- gargravarr 9y agoAs a general rule, high-frequency transmissions suffer from short range, particularly in an atmosphere. 5GHz was implemented in 802.11a in the early days of wifi, but suffered shorter range than 802.11b despite its higher bit rate. However, as it's not used as much by consumer devices, the spectrum is generally clearer so you get more consistent data rates. 802.11n and 802.11ac get around this by dynamically hopping between the two bands as necessary to get the clearest signal at the current distance.
- floatboth 9y ago> 802.11n and 802.11ac get around this 11n is available on both 2.4GHz and 5GHz. 11ac is 5GHz only. I don't think there's any specific hopping thing in n/ac. It's just normal roaming between APs with the same SSID, if you use the same SSID for both frequencies. Same roaming would happen with just 11a and 11g.