KTTW's transmitter shelter was physically relocated during the station's facility upgrade.SIOUX FALLS, S.D.
Like a lot of U.S. television stations in recent years, KTTW, the Fox affiliate here, underwent a major facility upgrade. Ours even involved relocation of the transmitter building.
We had to relocate to a new site as the lease on our old property was running out, and we saw this as an opportunity to move up to a more powerful transmitter and install a new antenna. Our old transmitting facility was constructed around an antenna with a low power handling capability and was well matched to the 50 W transmitter driving it. In our upgrade, we replaced the low power transmitter with a Harris Platinum 1000 that allows us to deliver more than a kilowatt to the antenna.
For our new antenna, we selected a Jampro JSL 7-bay VHF slot antenna from the company's Prostar series, as we wanted to increase our coverage area to the maximum the FCC would allow—about 50 miles. We chose the Jampro because it gave us the best value for the money and it could easily be mounted on the side of the tower structure, allowing us to achieve our desired coverage pattern.
CUSTOMIZED PATTERN NEEDED
We elected to have Jampro custom tailor that coverage pattern to a "bent peanut" shape, as the FCC required us to maintain our pre-relocation coverage area. This was a slight modification of one of Jampro's many patterns and after some amount of testing and tweaking at their California facility testing facility, they gave us exactly what we wanted.
Mounting the antenna on the tower was no problem, in spite of other stations' antennas already positioned just above and just below us on the new tower.
The KTTW antenna is mounted between two others at the 777-foot level on a common tower. The Jampro antenna is constructed of marine brass, copper and Teflon, so it has excellent weather resistance and a streamlined design to minimize wind load on the tower. Both of these attributes are very important up here in the Dakota winters. I should add that the JSL comes with sealed radomes, which will help us withstand the blizzard conditions that Mother Nature seems to dole out here every winter.
As part of the installation, Jampro supplied all the proper brackets and hardware, along with 840 feet of their ProLine 1-5/8 inch flexible transmission line necessary to connect with our antenna at the 777-foot level on the tower.
The new antenna has allowed us to reach our intended viewership despite the fact that we're at a bit of a height disadvantage in this market. Competing network affiliates here have their antennas on 2,000-foot towers and we're up at less than half of that elevation. We're also pleased with its operation. With the 7-bay Jampro, we're able to make our licensed ERP of 7.5 kW with the transmitter delivering only 1,060 watts of RF.
Jampro was very accommodating in answering our questions and working hard to procure the transmission line and all the hardware necessary to place the antenna into service. This was the first time I used a Jampro product and I'm very satisfied with the purchase. The antenna has provided excellent performance.
John Bennett has been a broadcast engineer since 1980 and is a broadcasting graduate of Mitchell (S.D.) Technical School. He may be contacted atjohnb@kttw.com.
For additional information, contact Jampro Antennas at 916-383-1177 or visitwww.jampro.com.
