49MHz is only used for short range "toy" applications, not for serious models. In the UK, 35 MHz is available almost exclusively for airborne model control (there are a couple of channels within it shared with low power telemetry signals). We also have access to 459MHz, shared with paging and other low powered telemetry systems, as well as 2.4 GHz.
As 459MHz is only used in the UK, there is virtually no commercial equipment available on this band. Anyone using it will likely have made their own equipment, or have modified 433MHz equipment.
The attraction of 2.4 GHz is that the combination of spread spectrum and frequency hopping offers a highly robust communications channel. Not only is the signal difficult (but not impossible) to jam, but the vastly greater bandwidth permits a much higher rate data transfer, as well as allowing more data to be transferred without introducing latency. This latter was an issue on the "narrow band" systems operating on VHF and UHF frequencies, where adding "fail-safe" information and the like introduced a perceptible time lag into the control response.
All type approved equipment on 2.4GHz has to be designed to minimise interference with other users of the band - even though this is inherent in spread spectrum operation.
Most model flying takes place in wide open spaces, so things like wifi or microwave ovens are not really an issue.
Moving on to the "drone" issue - there is actually no legal definition of a drone. All the legislation covering "drones" refers to "Unmanned Aerial Systems", or UAS. "Drone" is a popular term for these devices, but has no legal standing. UAS, as its name suggests, applies to any unmanned aircraft, be it an RC model, an autonomous (or semi-autonomous) multicopter or a Predator military aircraft.
Biting the hand that feeds IT
