I am trying to understand why there are different speed on different frequency bands. I see that e.g.
ZigBee can do 250kb/s for both 2.4GHz and 868/915MHz, but
WiFi are also 2.4GHz with much larger speeds, why are they different? How come 2.4GHz is so slow for
ZigBee and so fast for
WiFi when they operate in the same frequency band?
And is it possible to obtain larger speeds on lower frequency bands just by modulating the signal the same as
WiFi does? Is modulation impaired by lower frequencies or is it only dependent on how good the modulating hardware is?
Thank you very much in advance!