Fall 2008 Issue

Long-Range Summer 6-Meter Paths
Between The U.S. and Japan

The “Magic Band” is full of mysterious propagation modes.

Here WB2AMU comments on the Short-path Summer Solstice Propagation (SSSP) theory put forth by JE1BMJ.

By Ken Neubeck, WB2AMU

Figure 1. Plot of 50-MHz QSO between KØHA in Kansas and JE6URG in Japan. (Graph courtesy of Bill Hohnstein, KØHA.) The plot, constructed by Bill Hohnstein, KØHA, is of the 6-meter path between his QTH in Kansas and JA6URG, located in
southern Japan, during the summer of 2008.

During this past summer there were a number of interesting occurrences on 6 meters, particularly in the area of long-distance contacts being made, not only with the East Coast of the U.S. into Europe, but also to Japan into various parts of the U.S. during the months of June and July! This latter path has been the topic of intense discussion by many 6-meter operators regarding what the actual propagation modes are that cause dthis to occur.

In my previous article entitled “Observing the Double-Hop Sporadic-E Phenomenon on 6 meters,” which was published in the Summer 2008 issue of CQ VHF, I discussed the occurrence of double-hop sporadic-E during the summer months. Typically, the presence of certain multiple-hop sporadic-E paths has allowed for the eastern part of the U.S. to work into western Europe (e.g., Spain, Portugal, and the Azores). This path was observed regularly this past summer.

Also during this summer there were several days when high-power stations in Japan were able to work many stations in the U.S. running high and sometimes moderate power. A number of 6-meter aficionados have started using the phrase Short-path Summer Solstice Propagation (SSSP) to describe this path in lieu of the traditional multiple-hop Sporadic-E model. (For more information on SSSP, see the article by Han Higasa, JE1BMJ, elsewhere in this issue.) The introduction of this model has created a bit of controversy and a lot of thought-provoking ideas. However, because of the near-regular occurrences of the U.S. to Japan path on 50 MHz this summer, something besides the traditional multiple-hop sporadic-E model may be needed to explain what has been happening.

This article will examine both the SSSP model, the traditional multiple-hop model, and the feasibility of each. As this is a phenomenon that is relatively new, there has been a lot of speculation involving initial observations, and hopefully through careful study this subject can be addressed properly.

History of Japan to U.S. 50-MHz QSOs

Over the years there have been a number of contacts between Japan and the West Coast of the U.S. that have been recorded on 6 meters, both via the F2 mode during the high solar activity years and via multiple sporadic-E hops during the summer months. However, contacts between Japan and non-West Coast parts of the U.S. during the summer have been happening more often on 6 meters because of increased activity on the band, particularly with the appearance of high-power Japanese 6-meter stations.

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