VICTORIA, Canada—As the U.S. spectrum repack winds down, a “mini-repack” of sorts is taking shape north of the border. The Canadian DTV Allotment Plan—launched in 2015—essentially reconfigures the 600 MHz band across all provinces and territories, and includes new channel assignments for both high-power and low-power TV stations.
CHEK-DT, an independent TV station licensed to Victoria, B.C., relocated to UHF Channel 16 (from Channel 49) at the end of April as part of the DTV Allotment Plan. Owned by CHEK Media Group, a consortium of station employees and local investors, CHEK-DT primarily serves new programming to viewers in the southwestern area of the province.
The transition from Channel 49 to 16 was substantial enough to require a new transmitter. In addition, since the existing transmitter was nearing end of life, we decided to overhaul the entire system, including the STL and antenna. For the latter, we went straight to Dielectric, given our previous experience with Dielectric antennas, along with their industry longevity and engineering quality.
TOWER-ING JOB
We selected a TLP Series slot antenna from Dielectric’s Powerlite Series—specifically, the TLP-8M model—for the new Channel 16 assignment. The TLP-8M is an eight-bay, elliptically polarized directional antenna side-mounted on the tower at a height of 482.4 meters (1,582.6 feet) above average terrain. Dielectric customized the polarization to include a 30% vertical ratio to improve reception for viewers with indoor antennas.
The Powerlite Series is ideal for TV stations seeking an all-in-one antenna system. The Channel 16 system includes a wall-mounted filter and 1-5/8-inch rigid transmission line inside the transmitter building, among other essential RF components. The existing transmission line outside the building was retained and factored into planning for the new antenna’s size.
Mounting the new antenna proved a fairly simple job, requiring a small tower crew with a pulley system. We worked with Dielectric to ensure that our existing antenna-mounting hardware could be used, which simplified installation. We also specified an antenna of the same approximate weight and wind load, which eliminated the need to reinforce the tower structure. Dielectric’s sales and engineering departments stayed in touch with us throughout the design process, providing feedback and advice on the structural design and key performance specifications.
BOOSTING THE SIGNAL
As for performance, the new system is exceeding expectations in the early days. We had a close eye on VSWR performance, and immediately recognized that the VSWR was very low, with minimal return loss or reflection back towards the transmitter This ensures that the RF power transmitting through the system and out from the antenna is remarkably efficient. We have also noticed minimal signal loss through the new Dielectric filter, which contributes to the overall efficiency of our transmission system.
Signal coverage and quality has improved overall as well, notably in Victoria and Vancouver. Some of our viewers in low-lying areas, where we previously had signal strength challenges, have reported improvements in reception. This validates our strategy of enhancing the vertical component within the elliptical polarization, as the new antenna uses the same elliptical pattern and points in the same directional pattern as before.
Working with Dielectric has always proven simple, with outstanding communication and a desire to build systems that address our requests to exacting specifications. We anticipate that this antenna will remain in service for decades as we continue to broadcast to our local communities.
Kory Andersen can be reached at kandersen@cheknews.ca.
For more information on Dielectric, contact Kim Savage at kim.savage@dielectric.com.
