Emission of two high-power pulsed CO2-lasers with a transverse discharge at atmospheric pressure in the active medium and the output beam aperture <$E100~times~100> mm, united by a joint unstable telescopic resonator, was coherently summarized under conditions of real ground-level trackon the screen surface, which was remote from output mirror of the laser at a distance of 263 m. Output Brewster windows of laser cuvettes were manufactured from single-crystal plates of sodium chloride which had a diameter of 300 mm. Mirrors for resonator and optical circuit were manufactured from oxygen-free copper. Active medium - a mixture of gases: CO2:N2:He in the ratio 1 : 2 : 3. Laser pulse duration is 5 microseconds. During the experiment, when summing on the screen 2-laser beams at the lowest possible convergence angle of rays, the interference pattern was registered.