Hi Frank:
Thanks pal... guess I got a bit ahead of myself there!
Of course, you're completely correct! Should have been 26db, instead of 16dB!
73,
Tom
At 03:54 PM 3/30/05, you wrote:
Hi Tom,
Just a small correction to your 2W to 800W example:
From 2W to 4W (first doubling of power) = +3dB
From 4W to 8W (2nd doubling of power) = +3dB
From 8W to 80W (increase of 10X) = +10dB
From 80W to 800W (increase of 10X) = +10dB
Total = 3+3+10+10 = 26db
Best 73,
Frank - W6NEK
----- Original Message ----- From: "Tom Hammond" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>; <elecraft@mailman.qth.net>
Sent: Wednesday, March 30, 2005 11:01 AM
Subject: Re: [Elecraft] OT: math question
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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