The term "channel" related to RF transmitters is ambiguous. With small radio devices (SRD), it usually refers to assigned fixed bands within the frequency range covered by the transmitter. A reasonable channel width depends on the achievable frequency stability and the signal bandwidth. In case of FSK with 1Mbps signal rate, a channel width below MHz range makes no sense.
As another point, a FSK transmitter with several watts power in the 2.4 GHz band will conflict with RF regulations, I guess also in your country.