[BC] FCC rules independent study

[Jeff Glass]

Hello:

I'm studying  the rules regarding nighttime signal calculations and the FCC gives an example in 73,185 (d)  That has me confused. It says that a 260 mv/m towards an existing station will put in a 50% skywave  of .06217 according to 73.190 equation 1, whic is 50% skywave during SS + 6 hours. First, is there a graph I can use rather than the equations?  There is 73.190 Fig 1a, but that gives no indication of time period after SS.  FCC 73.190 Fig 1b gives the 50% skywave, but for SS + 2 hour. If I use either curve,  get a field that is much stronger than what the example gives.

Is there a chart available for 50% skywave, SS + 6 hours like formula 1?
I have not yet had a chance to code formula 1 into Mathcadd yet, so I prefer a chart for now, if that's possible.

Jeff Glass
Northern Illinois University