Above:  A crane hoists the radar dish of the WSR-57 radar to the 70th floor of the RCA Building in midtown Manhattan, on June 13, 1960. 

The following appeared in the May 1960 edition of Weather Bureau Topics:

Radar equipment for the Weather Bureau's new headquarters in Rockefeller Center has completed its spectacular climb to the 70th floor and is ready to be assembled.

The new storm-detecting radar includes a spun aluminum parabolic reflector, 12 feet in diameter, weighing 400 pounds; a 1500-pound cast aluminum supporting yoke; and an 800-pound electronic transmitter-receiver.

The hoisting of this equipment 850 feet up the north side of the RCA Building was done in two stages. A 35-ton truck crane with a 90-foot boom lifted the units from flat bed trucks to the sixth floor setback above Rockefeller Plaza. A derrick installed on the 69th floor then raised each piece of equipment 760 feet from the sixth to the 70th floor. To prevent the antenna and other units from swaying in the wind on their way up, two parallel steel cables were installed as guy wires 12 feet apart, stretching from I-beams at the 59th floor down to the 6th floor.

Each load rode up against the cables, which were kept taut with turnbuckles. The boom derrick and cables were welded to the building's structural steel framework to provide secure support. 

In spite of all these precautions, the raising of the parabolic reflector had to be postponed twice because of high winds. The engineers decided that it would be too risky to expose the "dish", which is light for its size, to winds of 15 to 20 miles per hour.

It is expected that the installation will be completed by August 1, when the new station including office space on the mezzanine floor of the RCA Building will become the headquarters of the Weather Bureau in New York City.

Addendum to the original story:

The New York City WSR-57 radar, on top of 30 Rockefeller Plaza, was decommissioned on September 26, 1995. Chris Stachelski, of NWS Eastern Region Headquarters, reports that the radar dome was taken over by WNBC-TV and used for their first Doppler radar. While they no longer use it for that purpose, the radar dome remains in its original location. Chris provided this photo from December 2016.