Topband: RE: skewed paths

[John Kaufmann]

On Mon, 17 September 2001, Robert Brown wrote:

 There, in my view, scattering plays a major role,
> making short-path signals look like signals from a "long-path"
> direction.
>  

First let me say that I give Bob credit for trying to explain these phenomena in scientific terms.  I come from an engineering background and can appreciate this.  

However, some of my own experiences seem to contradict the short-path/scattering hypothesis.  I have seen many lowband skew path openings to Asia and Oceania that have occurred at times when short path propagation is unlikely because the short path is almost entirely in daylight from end to end.  An example is my summertime path to VK6 on 80 in late afternoon.  In years when I monitored this path regularly, it opened on almost a daily basis and therefore would not seem to be connected with special geomagnetic conditions.  Another example is the skew path to southeast Asia around the same period of time.  The Singapore "beacon" on 3915 kHz provides a nice source for monitoring this path because it is a high power broadcast transmitter (around 75 kW as I recall) and is audible here almost daily throughout the entire year in the late afternoon.  What's in common here is that the short path is a nearly polar path to these regions, but the polar regions are in daylight between our spring and fall equinoxes, and especially around the summer solstice.  I tend to believe that skew path occurrences on 160 are correlated with 80 because on the occasions when I have seen skewing on 160, it was also very pronounced on 80.

I don't pretend to have an explanation for all this but these are some of my observations.

73, John W1FV