Page 2 of 2

Re: Limit power of exciter

Posted: Sat Jan 16, 2021 4:27 pm
by radium98
Oh many thanks .

Re: Limit power of exciter

Posted: Mon Jan 25, 2021 12:47 pm
by LeeCavanagh
Albert, what would i need to limit 100mw down to between 1mw and 30mw. ? Do i need a 60db attenuator?

Re: Limit power of exciter

Posted: Mon Jan 25, 2021 3:26 pm
by Albert H
The power P(dBm) in dBm is equal to 10 times the base 10 logarithm of the power P(mW) in milliwatts (mW) divided by 1 milliwatt (mW):

P(dBm) = 10 ⋅ log10( P(mW) / 1mW)

So,

1mW = 0dBm

100mW = 20 dBm

30mW = 14.77dBm

.....so you need a ~5.2dB @ 50Ω pad.

Your power reducer has to be made with carbon (non-inductive) or surface-mounted resistors so there's no inductance mucking up your results.

Three different pad options
Pad.jpg
If you go for the first option, you could use two 15Ω and one 82Ω resistors for a reasonably accurate result.

Re: Limit power of exciter

Posted: Mon Jan 25, 2021 5:46 pm
by LeeCavanagh
Thanks Albert