It is late spring, and we are moving into summer. This is mostly bad news. Have you noticed what has happened to 10 Meters? DX signals are weaker and activity is way down. I wish this phenomenon had a simple name. I picked up the phrase "summer absorbtion" in my teenage years, but have been corrected with a geeky technical description that I will not re-print here. In a nutshell, the sun heats up the ionosphere and thins it, leaving less ionization for bouncing DX signals. The MUF is thus lower than we would expect for a daypath. In summer it's going to get worse. 15 will deteriorate during June, but will bounce right back in August. 10 is in for a longer drought, and won't come roaring back until September. The optimistic Dx'er, however, will find what he is looking for on lower frequencies and on nighttime paths. The summer deterioration effects daytime paths, especially in northerly directions.
SHORT PATH: We still have an excellent month of 15 meter propagation left before the band goes south. It is open most of the night and all day, with pipelines to the Orient and YB in late morning. The USSR comes through in the evening and Europe around midnight at their morning peaks. The Pacific remains open very late. Paths are open at other times of the day to these same areas. 20 Meters will be excellent at night through the summer, with a wonderful grey line path to the far east after sunrise. Russians and Europeans will pound through all evening, with exotic Pacific and Asian workable during the pre-dawn hours. 40 will remain usable, but everybody will be on 20. 80 will be rough, but VK can be worked at sunrise on weekends.
LONG PATH: The primary LP circuits fade away during the summer, which is the Antarctic winter. The southerly grey line no longer leads all the way to Middle East. Our afternoon path to VK is less reliable, but the morning path to the Indian Ocean and the southern part of Africa will be FB for several months. Indian Ocean countries become very active on this path, and the pileups are fun. With the low summer MUFs effecting the northern areas, it will remain possible to work southerly long path on 15 and 10. Look for Europe on 15 around 1200Z - 1330Z.