Arecibo Ionosonde

Once of the things found in the storage area behind the Arecibo Observatory  is the ionosonde antenna. It's not there for storage, but located there, presumably so that it is further away from radio astronomy instrumentation, causing less interference. This is a dual polarized log-periodic HF antenna. I don't know which company designed and made this, but it is a beautiful antenna indeed. I happened to be there at the right moment, when there was a circular halo right above the antenna. 

The antenna sustained a bit of damage during the hurricane Maria, but I'm told that it will soon be operational again. I've got some ideas on using my spread spectrum ionosonde/HF radar concept there, so I hope the antenna is back up and running soon.

Arecibo ionosonde antenna. Dual polarization log periodic HF antenna.