On 3/5/2015, the FCC accepted for filing an application from WDTW, AM 1310, Dearborn, MI (more well-known by its historic calls WKNR and WNIC, among others), for a CP to build its facility at exactly the same site and same field ratios and phases as the array that was demolished on 1/2/13 after the station was taken silent. The only difference is that the new array would replace the lighted towers with ones that are top loaded and short enough to be unlighted.
I find myself questioning whether this has been well thought out. I'm a fan of both AM broadcasting and Mexican (as well as other forms of Latino) music, and I really would like to see the venture succeed.
If they had chosen to replace the lighted towers with new lighted towers of the same height, would they have had to make any application for a CP, or would they not have been able to simply rebuild (Taylor city government permitting) and just file a resumption of operations report with the FCC?
Operating 5kw into the daytime pattern with two towers would provide a useful signal (though not a very strong one) to all of the Detroit metro area, including a very good (about 12mV/m, give or take) to the Southwest Detroit area where the area's hispanic community (surprisingly small for a city of its size in this day) is somewhat concentrated.
The problem is that the 5kW nighttime pattern with six towers is very tight and with the channel's high interference level, the nighttime coverage will miss altogether the core of the area's Spanish-speaking community, where a typical night signal will be about 2 mV/m against a 12mV/m NIF level. Their night signal will boom over Detroit's West Side and southeast Oakland County, where the Spanish-speaking population is essentially zero (Pontiac, which does have Spanish-speakers, will only get about 6 mV/m at night - listenable though with obvious interference).
If they want to serve the Hispanic community on 1310, they will really need to build their array somewhere to the east, southeast of south of the existing array. Two towers (class D with LP low night power, pattern switch) right in southwest Detroit would cheaply deliver most of the metro area by day, with a booming (>100 mV/m) daytime signal in the core and an NIF signal in the core by night. Four towers a little further downriver would be even better. Being further away from WEXL, they may be able to use considerably more than 5kW daytime (the 5kW day level is, in part, a legacy from when 5kW was the maximum for Class III-A regionals). A four tower array would likely take the form of a rhomboid parallelogram, like those of WSPZ (or KRHW critical hours), but with the major lobe aimed at about 20°, and with the two south towers shorter than the north towers, allowing some groundwave in the nulls whilst effectively supressing high angle radiation that would interfere with stations close-in like WTLC, WIBA and WDPN.
Yes, I know that zoning boards and existing broadcast (73.1692) and non-broadcast (22.371) towers can make a new array very difficult, but if they really must rebuild at the existing site, they could save a lot of money by only building the two tower array for the daytime pattern and going class D (the daytime pattern has less than unity to the west, where WIBA is the most-protected station, so I'm guessing nighttime power using the daytime pattern would be somewhere between 50 and 100 watts). This would not be one iota less effective for a Spanish language station than building out the whole six tower array, which would be quite an expense (in addition to six 199' towers, the station's silent STA stated that their existing ground system is in disrepair - that's about 25 miles of thick pure copper wire!).
I really do wonder why their nulls to the east of their array need to be so drastically deep, inasmuch as WIBA to the west (5kW loose directional - this is the senior station on the channel - with more than 370mV/m @1km on the 115° radial) , WEMG to the east (250w omnidirectional with 155mV/m @1km in all directions), and WTLC (1kW DA with minor lobe to the NE with as much as 640 mV/m @1km on 23° radial), no station on 1310 anywhere in the northeast US has a low NIF in the first place. If they could "tweak" the phasing to provide a little more RF on the 70° radial, perhaps they could have a passable signal in SW Detroit (note that nighttime radiation on the radials in the direction of Ottawa are already well below the limits because of CIWW's high NIF from other stations on 1310) .
If the owner goes through with this, I really hope he has something up his sleeve, like an FM translator in SW Detroit, a nighttime-only synchronous AM repeater in SW Detroit (looks line an obvious application for a Valcom stick), or a plan to swap facilities with another AM.
1310 would have more potential for WMKM than it would have for WDTW, as it's next to 1340 on the dial (WEXL, also black gospel) and booms into the same areas (western Detroit and SE Oakland Co) where middle class urban audiences are found. (WMKM, for what it's worth, booms into SW Detroit and Downriver, which seems to be a growth area for the Hispanic market, though its night pattern is more toward central Detroit) . Can two stations with different owners LMA each other?
I find myself questioning whether this has been well thought out. I'm a fan of both AM broadcasting and Mexican (as well as other forms of Latino) music, and I really would like to see the venture succeed.
If they had chosen to replace the lighted towers with new lighted towers of the same height, would they have had to make any application for a CP, or would they not have been able to simply rebuild (Taylor city government permitting) and just file a resumption of operations report with the FCC?
Operating 5kw into the daytime pattern with two towers would provide a useful signal (though not a very strong one) to all of the Detroit metro area, including a very good (about 12mV/m, give or take) to the Southwest Detroit area where the area's hispanic community (surprisingly small for a city of its size in this day) is somewhat concentrated.
The problem is that the 5kW nighttime pattern with six towers is very tight and with the channel's high interference level, the nighttime coverage will miss altogether the core of the area's Spanish-speaking community, where a typical night signal will be about 2 mV/m against a 12mV/m NIF level. Their night signal will boom over Detroit's West Side and southeast Oakland County, where the Spanish-speaking population is essentially zero (Pontiac, which does have Spanish-speakers, will only get about 6 mV/m at night - listenable though with obvious interference).
If they want to serve the Hispanic community on 1310, they will really need to build their array somewhere to the east, southeast of south of the existing array. Two towers (class D with LP low night power, pattern switch) right in southwest Detroit would cheaply deliver most of the metro area by day, with a booming (>100 mV/m) daytime signal in the core and an NIF signal in the core by night. Four towers a little further downriver would be even better. Being further away from WEXL, they may be able to use considerably more than 5kW daytime (the 5kW day level is, in part, a legacy from when 5kW was the maximum for Class III-A regionals). A four tower array would likely take the form of a rhomboid parallelogram, like those of WSPZ (or KRHW critical hours), but with the major lobe aimed at about 20°, and with the two south towers shorter than the north towers, allowing some groundwave in the nulls whilst effectively supressing high angle radiation that would interfere with stations close-in like WTLC, WIBA and WDPN.
Yes, I know that zoning boards and existing broadcast (73.1692) and non-broadcast (22.371) towers can make a new array very difficult, but if they really must rebuild at the existing site, they could save a lot of money by only building the two tower array for the daytime pattern and going class D (the daytime pattern has less than unity to the west, where WIBA is the most-protected station, so I'm guessing nighttime power using the daytime pattern would be somewhere between 50 and 100 watts). This would not be one iota less effective for a Spanish language station than building out the whole six tower array, which would be quite an expense (in addition to six 199' towers, the station's silent STA stated that their existing ground system is in disrepair - that's about 25 miles of thick pure copper wire!).
I really do wonder why their nulls to the east of their array need to be so drastically deep, inasmuch as WIBA to the west (5kW loose directional - this is the senior station on the channel - with more than 370mV/m @1km on the 115° radial) , WEMG to the east (250w omnidirectional with 155mV/m @1km in all directions), and WTLC (1kW DA with minor lobe to the NE with as much as 640 mV/m @1km on 23° radial), no station on 1310 anywhere in the northeast US has a low NIF in the first place. If they could "tweak" the phasing to provide a little more RF on the 70° radial, perhaps they could have a passable signal in SW Detroit (note that nighttime radiation on the radials in the direction of Ottawa are already well below the limits because of CIWW's high NIF from other stations on 1310) .
If the owner goes through with this, I really hope he has something up his sleeve, like an FM translator in SW Detroit, a nighttime-only synchronous AM repeater in SW Detroit (looks line an obvious application for a Valcom stick), or a plan to swap facilities with another AM.
1310 would have more potential for WMKM than it would have for WDTW, as it's next to 1340 on the dial (WEXL, also black gospel) and booms into the same areas (western Detroit and SE Oakland Co) where middle class urban audiences are found. (WMKM, for what it's worth, booms into SW Detroit and Downriver, which seems to be a growth area for the Hispanic market, though its night pattern is more toward central Detroit) . Can two stations with different owners LMA each other?
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