Q John, K2CF, asks, “Sometimes on 10 or 15 meters I can make contact with stations that are 300 to 400 miles away. We can communicate, although we both report weak signals. The distance seems to be too great for so-called ‘ground wave’ propagation, and these stations are definitely in the skip zone, which would seem to preclude normal ionospheric propagation. Is there another mechanism involved?”
A The most likely explanation is that you are working them on what is known as “backscatter.” Within the skip zone a small amount of RF is scattered off the ionosphere itself, or from irregular ground at an intermediate reflection point within the zone. The levels are usually such that 100-W stations can just hear each other. Occasionally, you may also encounter situations where a sporadic-E cloud of intense ionization is located somewhere between you and another station within the skip zone. This cloud can reflect signals, creating what is known in amateur circles as “short skip.”
From QST April 2000
