On June 1st, 2008 we discovered this new radio site just east of the recently extended Hangar 19. The four towers, each with a small dome on top, are aligned along the east side of the hangar.
Similar sites can be found in locations associated with UAVs such as Creech AFB. We believe the site here and a similar site on the north end of Groom Lake that was installed around the same time are connected to a UAV project at Area 51 that began around 2008. That project very likely used the nearby Hangar 19.