From the legendary Steve Eberhart's (unfortunately defunct) KLIF tribute site:
"McLendon and KLIF had been attempting to upgrade the nighttime pattern for some time. The daytime pattern was excellent, but the nighttime pattern at the time was limited with only 1000 watts on a directional tower located on Scyene Road between Fair Park and Pleasant Grove (southeast of downtown).
In 1970, after extensive engineering studies, the FCC finally approved a new nighttime pattern with an upgrade to 5000 watts. The transmitter was installed in Rockwall, TX, some 30 miles northeast of downtown Dallas.
KLIF's nighttime tower arrangement is one of the more unique in the country. To protect other stations on the 1190 frequency, most notably WOWO in Fort Wayne, IN, KLIF had to install a
twelve tower directional system. The array is 1/2 mile long with two rows of towers 200 feet apart.
At the time, the FCC required meter readings every 30 minutes. There was no way to read all tower meters within the allotted time, so the station built a road between the towers with a turnaround on each end. A Jeep was purchased for engineers to drive from tower to tower to read the meters.
From the air, the tower arrangement resembles a landing strip. If fact, a plane actually tried to land there once thinking it was an airfield be fore realizing the error at the last minute and pulling up! Huge X's were painted on the paved strip between the towers, so that no future pilot would be mistaken.
KLIF's daytime coverage area was HUGE! This was not a station that just reached Dallas by any means. The daytime pattern was with the maximum allowable 50,000 watts. It featured a directional array with four towers located in south Irving. The pattern beamed north to up I-35 to Sulpher, Oklahoma; east to Longview; west to almost Abilene; and the south contour reached almost to Waco. KLIF had a city-grade signal over the entire north central Texas and southern Oklahoma map.
The nighttime pattern with 5000 watts was very narrow, appearing like a Zeppelin with a fish tails. The larger part aimed directly at and covered the city of Dallas and extended through the mid-cities of Grand Prarie, Irving, Arlington, and on to Fort Worth. The smaller "fishtails" reached Plano to the North, and the communities of Oak Cliff, Duncanville, and Lancaster to the South. To the east it reached the town of Terrel, but left much of its previously covered night pattern to the north to McKinney, Lewisville and Denton out of coverage. Not unlike many stations attempting to upgrade coverage areas, KLIF made a critical mistake with their new nighttime pattern. In the years since 1970, the population growth areas in the Dallas Fort Worth area have been to the north through Plano to McKinney and the corridor from Carrolton to Lewisville to Denton. All of that area had been covered with a city-grade signal in the previous 1000 watt pattern. No one could have predicted the growth to these areas which at the time were basically small farming communities. The 1000 watt pattern did not give coverage to Fort Worth prior to 1970 and McLendon wanted to blanket Dallas AND Fort Worth first and and had no reason to believe the population growth would be outside of the major cities of Dallas and Fort Worth. It was a gamble that in retrospect was successful in one way (achieving coverage in Fort Worth), but an error in another (not covering areas to the north which experienced growth in the coming years after 1970).
KLIF promos were immediately put on the air, "KLIF now with five times the nighttime power. If you live in Plano, Arlington, or Fort Worth, now you can get with KLIF night and day. KLIF, number one in Dallas...now number one in other cities!"
KLIF coverage map showing the two different nighttime patterns for KLIF's signal. The blue area is the original 1000 watt night pattern prior to 1970. The area within the black line is the 5000 watt pattern put on the air in 1970:
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