Laying Low(-VHF) in León
Low channel, low ERP, site height restrictions will reduce Canal Once coverage
The IFT last month uploaded five approvals for technical details of new IPN TV transmitters, mostly in the central and western parts of the country: Morelia, Manzanillo, Lázaro Cárdenas, Chilpancingo, and León. They are going to be uniformly tough catches for viewers, especially for viewers that up until now were served by Canal Once from an SPR transmitter, with ERPs all below 2 kilowatts and on mostly high-VHF channels.
But in León, a confluence of factors might have Canal Once laying low, figuratively and literally.
Low Power without Low Height
XHCPDP-TDT 3 León, when put in the PABF, contained an unusual restriction. The statutory coverage radius for it is only 30 km, and the IFT specified that the station should not be built in an “elevated place”. That was never going to truly happen because it meant the IPN would have had to set up its own transmitter site.
So, instead, it’s going up kind of high. It will be on Cerro Gordo, where the SPR’s tower already beams four TV stations to the region (SPR, Imagen, Multimedios, and Albavisión). The XHCPDP antenna will be 55 meters high on the mast (XHSPRLA is 58 meters up).
That means the ERP has to be reduced to compensate, like in an FM station class. Indeed, XHCPDP will have an ERP of 65.8 watts. Not 65,800 watts, not 658 watts, 65.8. (Yet that’s not even the lowest: Manzanillo has an ERP of 64 watts from a mountain on channel 12.)
Low Frequency
This is one of the handful of stations as part of the construction of the “double network” that is a low-VHF facility.
Digital low-VHF stations are notoriously tough to tune, a problem that for XHCPDP will be exacerbated by the anemic ERP.
A comparison of the coverage areas makes it very plain that if the SPR removes Canal Once from its transmitter in León, as is customary when an area goes from single to double network service, coverage of Canal Once will decrease. XHSPRLA offers fringe coverage of Lagos de Moreno, Jalisco, which isn’t even in the service area for XHCPDP (right) with its sharp directional pattern focusing on areas to the south. That said, San Francisco de Rincón may get better results from the new transmitter.
But any gains on paper may be overshadowed by the difficulty of receiving low-VHF stations on smaller antennas compared to XHSPRLA in the UHF band.
