KINDERSLEY, SASKATCHEWAN — The small Canadian community of Kindersley first took in the signal of CKVX nearly 11 years ago when the 50 W station lit up the airwaves. The low-power FM signal covered a radius of about seven kilometers (just over four and one-quarter miles), blanketing the immediate community but unable to reach a much larger audience share on the periphery.
We were recently afforded the opportunity to apply for a power increase to better service the larger community. We struck a deal with a local wireless company to collocate on an existing tower vacated by the CBC, and were approved for a full-power license that raised our TPO to 18.9 kW; and our ERP to 100 kW.
With 41 AM and FM stations spanning from northwest Ontario to Alberta, Golden West Radio’s stations differ in antenna design and manufacturer based on varying site needs. However, Dielectricwas our immediate choice for CKVX based on site characteristics, coverage needs and many years of positive experience with their products.
The tower extends just over 300 meters high (approximately 1,000 feet) on a site with appealing topology. Unlike much of the flatter Saskatchewan terrain, the tower site is situated on a rising hill with clear sightlines in all directions. With CBC’s vacated, top-mounted TV antenna still in place, we opted for a side-mounted position immediately below the TV antenna. With unidirectional radiation a key requirement, we opted for Dielectric DCR-C ring style antenna — a proven design that we have had great success with across our station group.
The topology eliminated the need to include null fill in the design, but we did request a negative 0.75-degree tilt due to the antenna height. We ordered an elliptically polarized design with a 70/30 horizontal-to-vertical pattern. Elliptical polarization provides the reception advantage of a vertical component without doubling the transmitter power output, as is required by circular polarization. This keeps our transmitter power below 20 kW, comfortably meeting our licensed ERP without increasing monthly power bills.
The higher gain of an elliptical design also reduced the antenna size and windload, simplifying the antenna installation and tuning. On the advice of our consulting engineer, we opted for a 10-bay design that was simple to install, lowering installation cost while meeting our transmitter size; and accelerating our ROI while delivering low total cost of ownership. Our collocation leases costs are based on the number of antenna bays so keeping that count down helps keep that monthly rate lower. The upfront cost of a larger antenna with more bays would have quickly canceled out the cost of a larger transmitter.
Installation was seamless. While the Dielectric ring design is lightweight, some minimal tower strengthening was required since the CBC TV antenna remained. After adding crossbars, the tower crew installed mounts, connected one line section to each bay, and hoisted each into position one by one. A 3-1/8-inch coax connection down the tower and into the plant finalized the installation.
Dielectric antennas are well regarded for their engineering design and quality, which contributes to a simple and straightforward antenna tuning process. Unlike many smaller broadcasters, we have our spectrum analyzers to take readings and measurements. With the provided fine match, we quickly achieved a return loss of better than 30 dB at ±100 kHz, resulting in a very comfortable VSWR.
One important design characteristic of our antenna order was the addition of radomes for ice and wind protection. Our wide-open, remote prairie location leaves us susceptible to inclement weather conditions. While some other antenna vendors offer radomes that protect only the antenna drive point, we felt that the remote location of this site warranted the 100 percent protection of the Dielectric radomes.
Having full protection ensures we do not have to send out a tower crew to de-ice the antenna after an ice storm. In the Canadian prairies, we have no guarantee when we might next get melting temperatures after an ice storm. Experience has taught us we could be in for prolonged power rollback time if the antenna isn’t protected properly during an ice storm. The Dielectric radomes do just that.
Our DCR-C antenna has performed exceptionally well since it began radiating our signal at higher power. We are achieving the predicted 0.5 mV contour and are meeting all coverage expectations. In fact, CKVX now has one of the largest coverage patterns in the province, and anecdotal listener response has been overwhelmingly positive. Dielectric’s outstanding sales and service support across antenna design, ordering, manufacturing and delivery kept everything moving on schedule and on budget.
For information, contact Kim Savage at Dielectric in Maine at (207) 655-8528; or visit www.dielectric.com.