Channel capacity grows with bandwidth and only logarithmically with the signal-to-noise ratio.
Shannon's 1948 result. Capacity grows only logarithmically with power, which is why more transmitter power buys so little and more bandwidth buys so much.
In practice
- A rural link that doubles its transmitter power gains a few per cent of throughput; the same link given twice the spectrum roughly doubles it.
- A team that adds staff to a communication-bound process gains little; one that widens the channel gains a great deal.