Back in 2018 we installed the SPIDER 300A 3-meter diameter radio telescope at the Etscorn Observatory of New Mexico Tech university in Socorro New Mexico (USA) near the Very Large Array. Now we’re back to upgrade it with the Radio-over-Fiber kit for SPIDER radio telescopes that improves system performance by removing typical signal loss of standard coaxial cables.

The Radio-over-fiber kit allows to replace standard coaxial cables, that connects antenna’s LNA units to the receiver, with an optical fiber cable and it’s the perfect solution in order to avoid typical signal loss that is normal when coaxial cables are used. First of all we installed the “Fiber optic digital converters” on the antenna, directly connected to the LNA units. The fiber optic cable exits from the upper protection cover (top-left part of the antenna in the image below) and runs in the center of the tracking system in order to provide the best cable management.

The SPIDER 300A radio telescope antenna at the Etscorn Observatory is located at around 40 meter distance from the control room where receiver and computer are located. We pulled the optical fiber cable in the underground duct that connects the SPIDER 300A radio telescope base to the control room. Another advantage of the optical fiber cable in respect to the coaxial cable is that it’s smaller so it’s easier to pull inside the duct during installation.

Inside the control room, we installed the “Fiber optic converter” that is connected to the fiber optic cable and to the H142-One radio astronomy receiver. This way the Radio-over-Fiber kit is applied to the actual radio telescope without the need to modify the receiver. The Radio-over-fiber kit includes also a variable attenuator that can be activated when the SPIDER 300A radio telescope is pointed to the Sun to prevent saturation caused by the very strong radio signal coming from “our” star.

SPIDER 300A radio telescope at Etscorn Observatory (New Mexico Tech university) near VLA is now upgraded with Radio-over-Fiber kit and ready to be used as a wonderful instrument for radio astronomy outreach and education! And of course we couldn’t miss a visit to the Very Large Array radio astronomy observatory that, thanks to its twenty-seven antennas (each 25-meter in diameter) deployed in a Y-shaped array, function as a giant interferometer!