12km isn't too bad actually for alignment unless you're using really high frequency (>10Ghz) equipment. Even then though you probably don't need specialized equipment other than maybe binoculars and a voltmeter[1]. I've taught beginners to align 24ghz radios at 12km by hand.

[1]The voltmeter is for quick feedback on the signal level as you aim. Many high-capacity wireless radios have a connection point on the back that will adjust voltage to match the current receive signal level (measured in dBm). That's usually the fastest way to watch the signal level as you aim, especially if you're hanging off a tower while you do it.