Artifact Details
![A metal antenna protruding from a small piece of concrete](/static/3c1d0eb1d04cb83f239b830cfb0bc293/c0173/Moscow-U.S.jpg)
The concealed location and magnetic connection kept the antenna from being discovered.
What looked like a concrete ball was actually a “gap-jumping antenna” removed from one of the preformed concrete columns in the embassy office building. US investigators called it “gap-jumping” because it coupled magnetically with a matching antenna in the adjacent column. This allowed data to be transmitted without a physical electrical connection.