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Old 3-Mar-2016, 6:30 PM   #4
rabbit73
Retired A/V Tech
 
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,747
The general rule for co-channel interference is that your desired signal must be at least 15.5 dB stronger than any other signal on the same channel.

ATSC Recommended Practice:
Receiver Performance Guidelines

Document A/74:2010, 7 April 2010
RECEIVER PERFORMANCE GUIDELINES

5.4.1 Co-Channel Rejection

Quote:
The receiver should meet or exceed the following thresholds for rejection of co-channel interference at the following desired signal levels (Table 5.1).


The general rule for adjacent channel interference is that your desired signal must not be any weaker than 33 dB as compared to the signals on either side of it.

5.4.2 Adjacent Channel Rejection

Quote:
The receiver should meet or exceed the thresholds given in Table 5.2 for rejection of first adjacent-channel interference at the desired signal levels shown above the columns therein.


These rules assume that the signals are in the same direction, they don't take antenna pattern into consideration, and there aren't any spurious signals created by IMD (Intermodulation Distortion) from strong signal overload (as ADTech said).
Quote:
or is this pretty much factored into the results page and anytime there is a C you are going to get knocked off
It is only factored in to the extent that you get an A or C warning to the left of a callsign in the report. You must make the calculation.
Attached Images
File Type: jpg Co-Channel Rejection Thresholds2.JPG (42.3 KB, 1041 views)
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Last edited by rabbit73; 3-Mar-2016 at 7:29 PM.
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