Influence of the distance on the bit rate

If the required system design is too constraining for a given specification, and then not achievable, we might lower our expectations and have a tradeoff between the desired bit rate and the range

f= 869,5 MHz B= 250 kHz PAR= 0.5 W

f= 5 GHz B= 500kHz EIRP= 1 W

We can notice the bit rate is dropping quickly with the range of transmission. Then, the video transmission can be lost if the aircraft moves just a little bit too far of the limit range.