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Noise Threshold
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24-Jan-2016, 2:02 AM
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rabbit73
Retired A/V Tech
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,747
Here are two Noise Margin diagrams of an indoor antenna without preamp. They are two versions of the same setup. Version 1 is the way Andy shows it with the minimum required SNR added to the thermal noise floor and then the tuner NF is added to that. Version 2 adds the tuner NF to the thermal noise floor and then the minimum required SNR is added to that, showing what goes on between NM 0/-91 dBm and the thermal noise floor at -106 dBm. Note that a signal stronger than NM 0 dB, namely NM +6 dB in this case, is needed at the input of the tuner to offset the 6 dB NF of the tuner.
Attached Images
NMdiagIndoorV1rev.PNG
(44.3 KB, 5077 views)
NMdiagIndoorV2rev.PNG
(44.6 KB, 5012 views)
NetNMV1V2.PNG
(41.3 KB, 7196 views)
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Last edited by rabbit73; 11-Sep-2017 at
10:00 PM
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