[Elecraft] OT: math question

[Larry Phipps]

For convenience, Mini-Circuits has a nice printable conversion table at 
http://www.mini-circuits.com/dg03-110.pdf

Larry N8LP



Tom Hammond wrote:

> At 12:01 PM 3/30/05, you wrote:
>
>> How would one calculate the amplifier gain (in dB) required to go 
>> from one
>> power level to another?  For example from 5W to 100W.
>
>
> 10 log(P2/P1) = 10 log(100/5) = 10 log(20) = 10 (1.30103) = 13.0103dB
>
> An easy 'rule of thumb' way to get a good idea of such levels
> is to remember that:
>
>   a power INcrease of 2  = approx. +3dB change
>   a power DEcrease of 2  = approx. -3dB change
>
>   a power INcrease of 10 = +10dB
>   a power DEcrease of 10 = -10dB
>
> So, to go from 5W to 10W output, you have 3dB GAIN
>     to go from 10W to 100W, you have 10dB gain
>
> Since dB's can be added, going from 5W to 100W = 3db + 10 dB = 13dB
>
> Similarly, if you went from 2W to 800W...
>
>   From 2W to 4W (first doubling of power) =  +3dB
>   From 4W to 8W (2nd doubling of power)   =  +3dB
>   From 8W to 800W (increase of 10X)       = +10dB
>                                           -------
>    Total power increase in dB     =         +16dB
>
> 73,
>
> Tom Hammond   N0SS
>
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