Current Noise Floor

A typical radar receiver would require a s n of 3 to 10 d b to distinguish the signal from noise and would require 10 to 20 db to track.

Current noise floor.

In radio communication and electronics this may include thermal noise black body cosmic noise as well as atmospheric noise from distant thunderstorms and. A skilled operator might only be able to distinguish a signal 3 db above the noise floor s n 3 db or 75 dbm. In the absence of any broadband noise sources 1 f noise or brownian noise the minimum noise level you can hope to measure in an electronic system is the thermal noise floor. Johnson nyquist noise thermal noise johnson noise or nyquist noise is the electronic noise generated by the thermal agitation of the charge carriers usually the electrons inside an electrical conductor at equilibrium which happens regardless of any applied voltage thermal noise is present in all electrical circuits and in sensitive electronic equipment such as radio receivers can.

The noise floor will naturally go up as the band opens at night as you are able to hear more distant natural and man made noise sources. In signal theory the noise floor is the measure of the signal created from the sum of all the noise sources and unwanted signals within a measurement system where noise is defined as any signal other than the one being monitored. Analyzing noise in general can be difficult as there are a variety of intrinsic noise sources and these intrinsic noise sources are unique to different systems. Noise is naturally stronger with decreasing frequency and s meters are rarely calibrated to any standard so a s7 noise floor on 40 meters may just be ordinary.