2. DECIBELS

4. The decibel (dB) is a logarithmic unit used to express the ratio of two values of a physical quantity, often power or intensity. It is not a unit of measurement such as a Volt.
One of the values of the ratio is often a standard reference value, in which case the decibel is used to express the level of the other value relative to this reference.
One decibel is one tenth of one Bel, named in honor of Alexander Graham Bell.
With reference to audio power, one dB is the smallest change an average human ear can detect.

5. NUMERAL SYSTEMS Name Base Numbers Eleven10
Decimal , 1, 2, 3, 4, 5, 6, 7, 8,
Binary ,
Octal , 1, 2, 3, 4, 5, 6,
Hexadecimal , 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F B

6. LOGARITHMS
A logarithm is a number that the base 10 has to be raised to equal a given number. It is also known as the power of ⁰ = 1 10·³ = 2 10·⁶ = 4 10·⁹ = 8 10¹ = 10 10² = ³ = 1,000 10⁴ = 10,000 …

7. The number of decibels is ten times the logarithm to the base 10 of the ratio of two power quantities. dB = 10log10 P1/P2(ref) dBm = power relative to 1 milliwatt dBi = the forward gain of an antenna compared with the hypothetical isotropic antenna dBd = the forward gain of an antenna compared with a half-wave antenna 0 dBd = 2.15 dBi

8. dB power ratio____________ 40 10,000 30 1,000 20 100 10 10 9 8 6 4 3 2 0 1

9. May the force (in dBs) be with you!
Bob Rod