Two nature trail projects at Green Bank Observatory required trail signage specific to both the topic of radio astronomy, as well as the unique nature of the environment where the observatory is located. This design illustrates the advantage of placing a radio astronomy observatory in a valley protecting the sensitive receivers from radio frequency interference (RFI) that may come from nearby cellular towers or industrial sites. Even the trees planted around the observatory help break up RFI from passing vehicles (spark plugs emit it!) or home electronics.
