The scale evaluates the significance of transmissions from Earth as a function of signal intensity and information content.
The San Marino Scale was subsequently adopted by the SETI Permanent Study Group of the International Academy of Astronautics at its 2007 meeting in Hyderabad, India.
In the original presentation given by Almár, the San Marino index, SMI, of a given event is calculated as the sum of two terms.
This term is logarithmic, and calculated as: For example, a signal which is 100 times more intense than the background noise at the same frequency and bandwidth would have an I value of two.
[3] A C rating of one is something like a stray radar pulse, lacking any information content and randomly directed.