KFAQ Transmitter Tour
October 18, 2003
Our host for the transmitter tour was Ray Klotz, chief engineer for KFAQ and KVOO. The KFAQ transmitter site is located on the south side of East 11th street between 145th E Ave and 161st E Ave in Tulsa. This site has been in operation since the late 40's. There are three large towers on the site and a single transmitter building. Pictures from the tour can be found on the OKVRC website under the Events area.
KFAQ operates at 1170 KHz at a power level of 50kw non-directional daytime, and 50kw directional nighttime. The directional pattern protects WWVA in Wheeling, West Virginia. The main transmitter is 25 years old. It was manufactured by Harris and sold to the station by Curt Lutz, our VP of the Tulsa chapter of OKVRC. It uses two 4CX1500 tubes for low-level power generation / modulation and two 4CX35000 tubes for the final power amplifier. The final tubes cost $8600 new. It uses a method of AM pulse modulation that was quite innovative when first introduced. The power supply for the transmitter runs at 25,000 volts. The transmitter consumes 109kw of AC power per hour when running.
There is also 10kw solid-state backup transmitter that was made by Nautel. This transmitter was on the air and running 4kw output when we visited the station, because of a recent power supply problem with the main transmitter. KFAQ is planning to purchase a new Harris 50kw solid-state transmitter within the next few months. As part of the upgrade they will also be installing a new digital AM system, which will run on the same frequency. AM digital service is new to the USA, and will provide "FM station" quality. Combination analog/digital radios will start to be available within the next few months, with a big marketing push in 2004.
The station has a new 75kw air-cooled dummy load that is connected to the transmitter that is off the air. Ray showed us some dramatic pictures of the old dummy load when it failed during a power failure recovery sequence.
An adjustable phasing system is used to generate the three antenna feeds for directional pattern operation at night. During the day, only the center tower is used, however one of the other towers can be used when needed for maintenance purposes.
The station is closely monitored with a Burk remote control system, and can be completely controlled from the studio, or even over a telephone line form anywhere in the world. It also pages station personnel on their cell phones when it detects any problems.
The station has three 450-foot towers, located about 250 feet apart in a straight line. These are ½ wavelength antennas. We were given a close up look at the towers and their impedance matching circuits, which are located in small buildings at the foot of each tower. The tower itself is the antenna, sitting on a ceramic insulator. The towers are rather unusual in design, because they are four sided - and six foot wide on each face. Normally, towers are three side and much smaller on the face. The larger dimensions provide wider bandwidth that is helpful for providing better audio quality for AM broadcasting.
Ray described the antenna lightening protection and matching circuitry in detail. The coils and capacitors were extremely large and very high quality. Everyone was impressed with the functionality and appearance of the matching system. Each tower has a 120 wire ground plane system buried 8-12 inches under ground. About half of the wires are 450 feet long, the rest are around 100 feet. The guy wires have ceramic insulators that break them up into electrically odd lengths. Ray also described how the electrical power for the tower lights is connected, an issue for all antenna towers. The towers are painted every seven years. Specialists are hired for all tower work.
KFAQ stands for "Frequently Asked Questions" which matches their recent change to an all talk format. Originally, the call letters were KVOO, which stood for the "Voice Of Oklahoma", and are still used on their FM station.
Everyone who attended the meeting had a great time, and we really enjoyed all the information that Ray shared about radio station operation, history and future plans. Ray was particularly good about describing technical aspects of the operation in an understandable fashion.