First let’s define NLOS vs. nLOS. nLOS is near line of site and NLOS is non-line of site. When installing wireless radios one should be aware of a thoretical field called the Fresnel zone. If the Fresnel Zone is free from any obstruction, then the path is considered Line of Site (LOS). If there is anything within the Fresnel Zone but blocking less than 60% this is considered nLOS. An obstruction covering more than 60% of the Fresnel is considered NLOS.
Now, the implications of a LOS vs NLOS vary greatly and depend on the type of obstruction. A solid surface may have less implication than a row of trees. For the sake of discussion let’s assume the obstruction is a row of trees. The implication for a NLOS path being attenuated by a row of trees would be a lower receive level. If you have a lower receive level, and less margin in your link budget then the effective througput would likely be reduced.
If you are having problems with a path and are not sure what the receive levels should be I suggest you download and map out the path using our free LINKPlanner utility. With LINKPlanner you can enter obstructions and it will help remove some of the guesswork from your troubleshooting. It’s a fantastic tool, check it out!