The boys were just finishing ham and eggs when Montoya returned. There was a broad smile on his tired face.
"The engineers say it can be done. They have a portable loud-speaker system, and there is an inverter, as you call it, at the transmitter. What is this inverter?"
"It's an electric generator," Rick explained. "Battery current turns it, and it produces 110-volt alternating current. But inverters aren't very efficient, and they take a lot of battery current. That's why we'll need as many batteries as we can carry."
"The chief radio engineer said he understood exactly what was needed. He will gather the materials and meet us at the airport. Now, I think we have time for coffee, and perhaps I can follow your example with ham and eggs. It will take an hour for the equipment to be ready. Also, I called my uncle. He will be waiting for our call."
"Did you get any sleep last night?" Scotty asked.
Montoya smiled. "Sleep? I have forgotten what it is. But perhaps if this plan of yours works, I will remember, eh? Then I can sleep tonight."
A check with the hotel desk told Rick that the scientists had left word that they were not to be disturbed until later in the morning except for an emergency. They had worked a good part of the night, apparently with no satisfactory results.
The boys waited until Ricardo Montoya had breakfasted, then rode with him to the airport. There was another wait while the radio engineers arrived, bringing the loud-speaker equipment.
Rick supervised the placement of the amplifier in the rear seat. The inverter was placed on the floor, and wedged into place with scrap lumber. The automobile batteries were put into the luggage compartment behind the rear seat and were also wedged in place.
Wires were run from the amplifier through the rear-seat windows, which were opened just enough to take the thin cables. The leads were then brought out to the plane's struts. Two large loud-speakers were attached to the struts. At first there was some difficulty in figuring out a secure attachment, but the chief engineer, a resourceful type, managed to find a pair of U bolts somewhere in the hangars. They did the job nicely.