What happens to reception if a new building is erected or trees/bushes grow up between two installed radios?
Adding more molecules for radio waves to pass through (i.e. air being replaced by a building or trees) will naturally cause attenuation of the signal. This is why we recommend that radios be installed with a 10-20dB fade margin. The fade margin is the extra signal strength beyond what is necessary for reception. On OMNEX radios, the RF LED remains ON solid when you have a greater than 20dB fade margin; it flickers rapidly when the fade margin is less than 20dB, and it flashes slowly when threshold is reached and the link is lost. Using the example of leaves, if two radios are installed in the winter time and the RF LED is solidly ON, leaves filling the trees in spring will likely not affect the link. If, on the other hand, the RF LED is rapidly flashing during a winter installation it would be a good idea to adjust antenna placement or increase antenna gain to get a solid ON so that you have enough margin to take care of additional leafy attenuation in the spring.
