How much does increasing a receiver’s bandwidth from 50 Hz to 1,000 Hz increase the receiver’s noise floor?

Explication

Thermal noise power is proportional to bandwidth, so the noise floor rises by ten times the base-ten logarithm of the bandwidth ratio. Widening from 50 Hz to 1,000 Hz is a factor of 20, and 10 log₁₀ 20 is 13 dB.