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Re: [IRCA] CHOK was CBA-less 1070
> I also think something is amiss with CHOK's night pattern
> as they seem too easy here in NE IL and also note that
> CKOC 1150 has seemed too strong here for their night
> pattern for nearly a decade.
Probably a good time to remind all that the patterns displayed on various lists and books are ground level, zero degree elevation. As the propagation angle increases, the pattern changes significantly. What was a null could be a fairly powerful lobe or vice versa. For example, WDDZ-550 has a cardiod pattern with a minor lobe aimed right at WDEV-550 in VT. Yet at the appropriate elevation angle for propagation to Vermont, that lobe turns into a null. A two tower pattern with a single null at ground level may have no null at all when the angle goes up to 20 or so degrees.
If you are closer than 500 miles or so to a station, their pattern may well be somewhat different than what is shown on the diagram.
There is at least one pattern configuration where this doesn't happen. If you are broadside to a two tower array with a 180 degree phasing, that pattern is the same for all elevation angles, minus the lower efficiency as the angle increases. Same figure-8 shape and the null aims the same way.
Something to keep in mind...
Craig Healy
Providence, RI
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