It happened around 4:00 p.m. Wednesday at a Lockheed Martin Facility, located in the 300 block of Centerton Road in Moorestown.
Police say the 65-year-old contractor for Honeywell in Maryland was stricken while working on the mast.
Rescue crews performed CPR and were able to get him down.
The man was taken to Virtua Memorial Hospital in Mount Holly for treatment. There is no word on his condition at this time.