Thread: Noise Threshold
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Old 24-Jan-2016, 2:34 PM   #9
Retired A/V Tech
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,569
Here is a Noise Margin diagram for an outdoor antenna with and without a preamp with weak signals. As with an indoor antenna, the preamp not only compensates for distribution losses but also allows the reception of weaker signals than without a preamp; in this case from -2 dB NM to -7 dB NM. Only antenna gain can improve the NM to the point that the NF of the tuner is exceeded without a preamp or the NF of the preamp is exceeded with a preamp.

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File Type: png NMdiagOutdoorRev.png (62.2 KB, 2939 views)
If you can not measure it, you can not improve it.
Lord Kelvin, 1883

Last edited by rabbit73; 11-Sep-2017 at 10:13 PM.
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