If you are reading this then another radio event of possible interest is the upcoming Arecibo ionosphere HF heating campaign during 24 to 31 July 2017. The new Arecibo ionosphere HF heater nominally transmits 600 kilowatts net power (100 to 200 megawatts effective radiated power) and has a unique Cassegrain dual-array antenna design that increases gain of three crossed dipoles for each band using the signature 1000 ft spherical dish reflector. Read more about the Arecibo HF facility at http://www.naic.edu/~astro/ao50/Arecibo_50th_Paper_Breakall_revised_Oct_23_2013.pdf
During the upcoming campaign, the Arecibo HF transmitter is limited to two frequencies, 5.125 and 8.175 MHz. Campaign HF transmissions will start at approximately 1600 hours UTC and be active approximately 24 hours per day, with some occasional downtime for maintenance and other activities lasting one or more hours. Generally, the 8.175 MHz transmissions will occur in the daytime when foF2 is expected to exceed that value, between approximately 1830 and 2230 hours UTC. Otherwise the HF transmissions will occur at 5.125 MHz. The Arecibo incoherent scatter radar (ISR) will also be active throughout most of the campaign, but since it operates in the UHF band at 430 MHz long distance propagation is not expected.
These transmissions will be in the vertical direction so this is an excellent opportunity to observe NVIS from a powerful transmitter in Puerto Rico. My own experiments are O-mode polarized CW (kicking off the campaign at 1600 hours on 24 July 2017 UTC) for measuring plasma wave and turbulence effects. Experiments by other scientists may use X-mode polarization. To the best of my knowledge, all experiments will be CW with no amplitude or frequency modulation.