Mexican radio amateurs have been providing communication support from a fire scene in a remote area to civil protection authorities in Monterrey, Mexico. Two-member teams of volunteers have been flown in via helicopter since May 20, the first day of radio support, when the fire had already been burning for a couple of days. The fire in Pajonal — about 20 kilometers south of Monterrey — covered more than 200 acres in rough terrain. Temperatures have topped 100 °F.

Fueled by hot and dry conditions, Mexico’s 2019 fire season has been intense, leading to poor air quality. As of mid-May, more than 100 wildfires were active in 17 Mexican states.

Teams had been using Winlink but added the weak-signal software Vara HF, after José Alberto Nieto, EA5HVK, provided a Vara license on short notice. Tom Whiteside, N5TW, in Georgetown, Texas, has been supporting the effort from across the border. He has 40- and 20-meter arrays pointed in the direction of the fire in Nuevo Leon. Alfonso Tamez, XE2O, president of Mexico’s IARU member-society Federación Mexicana de Radioexperimentadores (FMRE), has been among the volunteers.

In addition to HF digital traffic, the volunteer teams have been taking advantage of VHF repeaters. HF antennas consist of a 40-meter dipole for 40 and a steerable portable dipole. A generator is providing electrical power.

On May 23, the team had to be pulled out of the fire zone due to severe thunderstorms. Amateur Radio support for the fire teams was planned to continue at least until May 30, at which point the need for continued support would be evaluated.