Interpreting PropView Graphs
Dave Bernstein <dhb@...>
After generating a prediction for propagation between two locations,
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check "Show Critical Frequencies" and uncheck "Show Open Bands". The black curve represents the lowest useable frequency (LUF) as a function of time. Any frequency lower than the black curve will not support communications due to absorption. The blue, green, and red curves provide a statistical range for the maximum useable frequency (MUF) as a function of time. The actual MUF will be at or above the blue curve with 90% confidence, at or above the green curve with 50% confidence, and at or above the red curve with 10% confidence. Any frequency above the actual MUF will not support communications, due to insufficient reflection. So at any specified time, you can identify which frequencies will likely support communication between the specified locations: they are bounded on the lowend by the black curve, and on the highend by the statistical range between the blue and red curves. You can use the green curve as a kind of "expected MUF" curve; being an optimist, I tend to use the red curve for this purpose. To make it easier to see what ham bands are open when, uncheck the "Show Critical Frequencies" box and check "Show Open Bands". Horizontal lines represent ham bands lying between the LUF and statistical MUF. The thickist lines indicates openings based on the 90% confidence MUF (the blue curve), and the thinnest lines indicate openings based on the 10% confidence MUF (the red curve). If you now check "Show Critical Frequencies", the relationship between horizontal lines and critical frequency curves should be apparent. Suggested corrections, improvements, and/or clarifications to the above would be appreciated; I'll incorporate the result into the online help. 73, Dave, AA6YQ
 In dxlab@y..., "Richard B Drake" <rich@w...> wrote:
Ron,

