Calibration and testing of the MEXART antenna using solar transits

The Mexican Array Radio Telescope (MEXART) is intended primarily for making observations of interplanetary scintillations (IPS). It consists of a 64 × 64 array of full-wave dipoles, operating at 139.65 MHz. The dimensions of the array are 69 m × 139 m. This array is being built in the state of Michoacan, located 350 km north-west from Mexico city (lat. 19°48′N, long. 101°41′W and 1964 m above sea level). We describe the initial tests of the antenna pattern by measuring the solar transits during the epoch (June-July 2004) that the Sun passed very close to the observatory's zenith. Observations made using different east-west rows (64 dipoles) agrees with the predicted theoretical beam pattern. The differences in the gain measurements provide important information to correct some problems with the dipole assembly, baluns and amplification system.