Frequencies in the microwave band (which includes 2.4Ghz and 5Ghz) are more readily absorbed by objects, rain and moisture in the air.A higher frequency (more cycles per second) uses more energy (power) than a lower frequency which means, given the same power input, there's less RF (Radio Frequency) energy output.There are several reasons why higher frequency has lower range: Wi-Fi, on the other hand, uses the much higher frequencies, with 5Ghz having lower range than 2.4Ghz, assuming the same power input. Short wave can increase range further by tropospheric propagation (bouncing the signal off the Earth's troposphere). Short wave uses much lower frequencies compared to Wi-Fi, down to around 0.003Ghz (2 MHz) so the longer range is ideal for those applications and can travel thousands of Kilometres. 'Short Wave' radio is used by amateur radio (ham) operators, maritime users and long-distance radio stations (world services etc) and international propaganda broadcast. So, a 900Mhz signal would travel further than a 2.4Mhz signal, everything else being equal. Lower radio frequencies have longer range than higher frequencies. When the waveform crosses the X axis, it's at 0 °, it rises to the peak (90 °), back down to the X axis (now 180 °), down to the bottom of the trough (270 °) and then back to the X-axis (360 or 0 °). We draw waves as graphs as we can show frequency variations and time but it's still just a stretched out circle. A 1Hz signal would rotate 0-360 ° once a second. Waveforms are generally drawn as above - as a graph of amplitude over time but you could also draw it as a circle because a wave (more specifically, a sine wave) rotates from 0 to 360 degrees each cycle. If you have more waves per second, the distance between each peak is shorter, therefore wavelength and frequency are inversely proportional - increase one and the other reduces, and vice versa. Wavelength (measured in cm or metres) is the distance from one point on a waveform to its next occurrence - literally the 'length of the wave' for example from one peak to the next.įrequency (measured in Hertz) is the number of times (or cycles) that a wavelength cycles per second. Radio signals exist as waves and can be drawn as a waveform. Frequency & Wavelengthįirst, a little basic physics recap. In this article, I'll explain the benefits and downsides of the 5Ghz band compared to the more commonly used 2.4Ghz band. More recently, the 5Ghz band has been used for 802.11ac and again now for the latest 802.11ax standard. The 5Ghz band was used for 802.11a, introduced in 1999 but 802.11a wasn't widely adopted - later systems such as 802.11b through to 802.11n used the 2.4Ghz band. Usage of the 5Ghz Wi-Fi band is increasing.

Wifi speed 2.4 vs 5