Besides increasing the availability of data links it is necessary to focus on the accuracy and reliability of testing optical links. Research of the data optical links is focused on the transmission of a large amount of data whereas the testing FSO link is designed to achieve maximal resolution and sensitivity thus improving accuracy and repeatability of the atmospheric effects measurement. Given the fact that testing links are located in the measured media, they are themselves influenced by it. Phenomena such as the condensation on transceiver windows (rain, frost) and the deviation of the optical beam path caused by the wind are referred to as non-standard effects. Non-standard effects never occur independently; therefore we must always verify the cross-sensitivity of the testing link.
In the paper we respond to an increasing number of articles dealing with influence of the atmosphere on the link but ignoring the cross-sensitivity of the testing link on other variables than tested. In conclusion, we carry out qualitative and quantitative analysis of self-identified non-standard effects.