The white device is an antenna radiator. It is connected to an identical device at the other end of the "rusty pipe" (an electromagentic dipole uniter). The whole assembly is the only remaining piece of the UFO that crashed here in the 1950s; all other sections were removed to prevent local residents and workers from discovering the wreckage and starting a panic that would be difficult to deal with. It spans an unused railroad grade on a hillside in the western USA.

This was left in place in the hope of recording transmissions that it receives from across the galaxy (so far, nothing other than inter-galactic sitcoms and shopping lists have been identified). Note how the vegetation to the right of the radiator has been supressed by the uniter's conversion of electromagnetic pulses it receives from who-knows-where.

The story behind the cover story is interesting. The white device is made out to be a security fence ofor a gas pipeline. Its alleged purpose is to keep kids off the pipe, where they might get hurt. When someone at Covert Ops came up with that idea, no one believed it would fly (pun intended). The guy sure had balls for suggesting it. But a test using a focus group proved him right: 100% of the testees (those taking the test) fell for it. The Director of Covers approved the idea without hesitation.

Implementing the plan was simple: operatives attached authentic-looking "gas pipeline" signs to the radiators---using insulating material, of course---and installed covert monitoring devices to inform Site Intelligence of the approach of any local idiots who might be tempted to play around on it. It works like a charm.