The military generally tests its systems over the US and allied countries.
The E-8 JSTARS manned aircraft has been able to track vehicles on the ground since...I dunno, I was in one in 1988 I think. Even the AWACS picked up traffic on the autobahn, because it was going fast enough for the system to flag it. Some claim the JSTARS equipment has the inherent capability to track dismounts (individual people). The balloon is a logical follow-on, especially with continuing miniaturization and price reduction of computing power and the growth of military networks. It would make sense to test all this over friendly territory before you go try it out on the less friendlies.
The E-8 JSTARS manned aircraft has been able to track vehicles on the ground since...I dunno, I was in one in 1988 I think. Even the AWACS picked up traffic on the autobahn, because it was going fast enough for the system to flag it. Some claim the JSTARS equipment has the inherent capability to track dismounts (individual people). The balloon is a logical follow-on, especially with continuing miniaturization and price reduction of computing power and the growth of military networks. It would make sense to test all this over friendly territory before you go try it out on the less friendlies.