Limit power of exciter

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radium98
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Re: Limit power of exciter

Post by radium98 » Sat Jan 16, 2021 4:27 pm

Oh many thanks .

LeeCavanagh
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no manz can test innit
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Re: Limit power of exciter

Post by LeeCavanagh » Mon Jan 25, 2021 12:47 pm

Albert, what would i need to limit 100mw down to between 1mw and 30mw. ? Do i need a 60db attenuator?
Sony ST 920 QS

Albert H
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Re: Limit power of exciter

Post by Albert H » Mon Jan 25, 2021 3:26 pm

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.
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LeeCavanagh
no manz can test innit
no manz can test innit
Posts: 129
Joined: Sat Feb 18, 2017 5:56 pm

Re: Limit power of exciter

Post by LeeCavanagh » Mon Jan 25, 2021 5:46 pm

Thanks Albert
Sony ST 920 QS

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