Arecibo Observatory in Puerto Rico is conducting an ionospheric heating campaign July 24-31, using HF.

“The new Arecibo ionosphere HF heater nominally transmits 600 kW net power and has a unique Cassegrain dual-array antenna design that increases gain of three crossed dipoles for each band, using the signature 1000-foot spherical dish reflector,” explained Chris Fallen, KL3WX, a researcher at the University of Alaska-Fairbanks HAARP facility. He has reported that Arecibo would use 5.125 or 8.175 MHz, depending upon ionospheric conditions, but emphasized that these are estimates and frequencies may be adjusted slightly. On July 25, Arecibo was transmitting on 5.095 MHz.

According to Fallen, campaign HF transmissions will start at approximately 1600 hours UTC and continue for approximately 24 hours per day, with some occasional downtime. Transmissions will be aimed directly upward, “so this is an excellent opportunity to observe NVIS from a powerful transmitter in Puerto Rico,” Fallen suggested. In general, the approximately 8.175 MHz transmissions will occur during daylight hours, between approximately 1830 and 2230 hours UTC. Otherwise, HF transmissions will be on or near 5.125 MHz.

Angel Vasquez, WP3R, the head of Telescope Operations and Spectrum Manager at Arecibo, said a QSL for reception reports may be had for an S.A.S.E to KP4AO club station QSL manager W3HNK.