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Old 25-11-2012, 21:21   #23
ferretuk
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Re: Inaccurate downstream power levels reported by SuperHub?

Quote:
Originally Posted by Sephiroth View Post
Amplitude ratio has no meaning in this context. The measurement on the SH is in dBmv. The reference power level at 0 dBmv (1.33 nano-Watts). Power is what matters in order to receive an intelligible signal. +3 dBmv doubles the power level.
Amplitude is relevant as the SH gives a voltage reading not a power reading. It is, however, academic as no-one likely to put a 'scope across the feed

You've agreed with I said:

Quote:
Originally Posted by ferretuk View Post
The modem reports in dBmV - An increase of 6dB in this figure would mean that the signal amplitude had doubled and the received power would have gone up by 4.
The confusion, as I also said, is that the modem reports an amplitude but labels it as power. The reference level quoted is 0dBmV (i.e. 1mV) which equates to 1.33nW into 75R
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