1

For ‘Rule of 10s and 3s Example 1’ you will

double the power three times and calculate the

corresponding dBm values.

2

dBm mW

+-

*÷

310102

0 1

Start off with the template.

Rule of 10s and 3s Example 1: Double the mW three times and calculate the dBm values.

3

dBm mW

+-

*÷

310102

0 1

=2

The first step is to enter the first

multiplier.

*2

Calculate the new mW value by multiplying the current mW value (1) by the multiplier (*2), and then

enter the new value in the mW column.

Rule of 10s and 3s Example 1: Double the mW three times and calculate the dBm values.

4

dBm mW

+-

*÷

310102

0

=3

1

=2 *2

Remember that whatever you do to one side, you must do the correlative

mathematics on the other side. Since you multiplied on the right, you must add on the

left. And since you multiplied by 2 on the right, you must add 3 on the left.

+3

Rule of 10s and 3s Example 1: Double the mW three times and calculate the dBm values.

5

dBm mW

+-

*÷

310102

0

=3

1

=2

=4

You double the power a second time.

*2

*2

And calculate the new mW value by multiplying the current mW

value (2) by the multiplier (*2), and then enter the new value in the

mW column.

+3

Rule of 10s and 3s Example 1: Double the mW three times and calculate the dBm values.

6

dBm mW

+-

*÷

310102

0

=3

=6

1

=2

=4

*2

*2

Again, whatever you do to one side, you must do the correlative mathematics on the other side. Since you multiplied on the right, you

must add on the left. And since you multiplied by 2 on the right, you must add 3 on the left.

+3

+3

Rule of 10s and 3s Example 1: Double the mW three times and calculate the dBm values.

7

dBm mW

+-

*÷

310102

0

3

=6

=9

1

2

=4

=8

*2

*2

*2

All that’s left is to double the mW side one more time and add the correlative +3 to the dBm side.

+3

+3

+3

Rule of 10s and 3s Example 1: Double the mW three times and calculate the dBm values.

8

dBm mW

+-

*÷

310102

0

3

6

9

1

2

4

8

*2

*2

*2

So you know that 2 mW = 3 dBm and 4 mW = 6 dBm and 8 mW = 9 dBm. The two columns of numbers are equal. They are just

presented using two different units of measurement.

+3

+3

+3

Rule of 10s and 3s Example 1: Double the mW three times and calculate the dBm values.