I was just looking at the Proofs of Performance done on the Daytime WDEO 990 DA near Clark Rd., North of Ypsilanti. Several Radials were included in the WMVP 1000 Application when they went to a new DA system. This was done to show that the first adjacent signals didn't have prohibited overlap. The Proofs were done by Munn Reese. They show that the area generally West of the new WCXI 1160 array are fairly close to 4 mS/m, not the M-3 value of 8 mS/m. The M-3 value was used to determine the overlap received from WYLL 1160. The deepest null in that direction in the present WCXI DA is on the order of 160 mV/m @ 1 km. Given the actual conductivity, that null could be increased to the order of 400 mV/m @ 1 km without overlapping the WYLL interfering contour. This is equivalent to increasing the "ERP" from roughly 250 watts into a 90 degree tower to an "ERP" of roughly 1600 watts into a 90 degree tower. The conductivities for WYLL were also found to be substantially less toward WCXI, but the WCXI conductivities have not been studied because there was a Method of Moments performed on the DA and not a full Proof of Performance. By letting the nulls out by changing the pattern (there are plenty of towers and options available for study, such as a two tower pattern vs. three), would allow better service to the greater Livingston County, the Fenton COL, and North Washtenaw County areas. A modest power increase may even be possible, though 50 kW would probably be too expensive from a power consumption standpoint with today's AM market realities. Increases in other directions, including to the East and South, may also be possible. Other stations in the state could probably operate at close to 50 kW, but have opted to stay near the 25 kW level, like WMKT 1270, which had a CP for 50 kW nondirectional Days but stayed at 27 kW to save power.
WDEO Proof of Performance Radials reprinted in WMVP application. WDEO is about 20-25 miles from the WCXI site, and the areas traversed by the radials are in areas which WCXI might improve service.
https://licensing.fcc.gov/cdbs/CDBS_Att ... &exhcnum=3