LOS ANGELES—The spectrum repack has produced unique challenges and situations to almost every affected broadcaster. Perhaps no case study is as compelling, or rare, as being repacked from UHF to low-band VHF.
Such is the case at KWHY-TV in Los Angeles. One of the first TV stations to broadcast in the city (as KBIC-TV in 1954), the station has served Los Angeles’ Spanish-speaking community since 1991, operating on UHF Channel 42 since its transition to digital in 2009. As an independent broadcaster—Meruelo Media purchased the station in 2016—it became clear moving to VHF would be our most economical option. As part of the TV Repack, the station received its Phase 2 Notice with a VHF Channel 4 assignment, broadcasting from a shared tower site on Mt. Harvard.
A CHALLENGING SWITCH
The move presented several technical concerns. For one, indoor VHF reception is a challenge, and would require proactive viewer education about antenna selection. Second, the fact that KWHY was moving to low-band VHF—an even scarcer scenario—left few professional supplier options. Third, with a fairly short, shared tower structure, a much lighter and condensed antenna was required versus the traditionally very large, low-band VHF systems.
Of the companies evaluated, only Dielectric could meet these three requirements, while also delivering the broad coverage patterns KWHY needed.
Following a mechanical analysis that determined that the tower structure could not support a low-band VHF panel antenna array, Dielectric engineers custom-designed a segmented helical antenna, borrowing technology from its DCR radio antenna family.
Widely used in high-power FM radio transmitter sites, the Dielectric DCR series of antennas provides full bandwidth, high-power handling capability and excellent elliptical polarity axial ratio. Dielectric’s low-band DCR-Q VHF antenna offers all of these features, plus the directivity required to fulfill the KWHY FCC construction permit and maximize their coverage over the L.A. market signal.
Consisting of eight circularly polarized ring-style radiating elements, the DCR-Q reduces the weight, wind load and required tower space to a fraction of that required by a traditional low-band VHF panel antenna system. The DCR-Q design is also ATSC 3.0-ready.
The station was originally allotted 3.7 kW of power, which would serve only a small percentage of the Los Angeles DMA. Following legal challenges, the ERP was increased to 35kW when station representatives presented a directional pattern that matched the contour of the largest station in the market. In a clever arrangement, the directional pattern is created by the positioning of the radiating elements in relationship to each other and the metal tower structure.
Dielectric’s outstanding customer service extended into (and beyond) installation. The design team continued its work as tower crews prepared to bring the old antenna down and run new transmission line, also supplied by Dielectric. A 60-foot structure was added to the top of the tower, allowing KWHY to operate both antennas for a brief period and make a clean break to VHF.
The new Channel 4 system, which includes a GatesAir Maxiva VAXTE air-cooled transmitter, went on the air on April 10—just days before the Phase 2 deadline. With the coverage and performance solidly meeting our expectations, KHWY continues its efforts to educate viewers on antenna selection, with the goal of serving and supporting the local Hispanic community.
David Gray can be reached at 760- 275-9897, or via email email@example.com.
For more information on Dielectric, visit the company’s website atdielectric.comor call 800-341-9678.
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