This dish alignment aid produces a loud (make that very loud tone with a pitch proportional to the signal strength. Basically, you hunt for the satellite you want and keep adjusting the dish until you get the highest pitched sound.
It sounds simple - and it is. The Canary is capable of reacting to signals from 500MHz to 2500MHz, so the whole satellite IF spectrum is well covered.
Two F-connectors at one end of the couple-of-matchboxes-sized unit connect to the LNB and the cable to the receiver. It is possible for the receiver to power the Canary (it will accept any voltage from 9-35V), but if you haven't got the cable in position at this stage, a 9V battery connected to an F-plug will do the job instead.
Two small connectors at the other end can be used to connect to a multimeter to provide a digital or meter reading. The meter should be set to either 0-3V or 0-2mA, and then larger readings will mean stronger signals. If the meter is set to the current reading then this mutes the tone too, which is useful if you're working inside or the like.
It's not a new idea, but the Canary is well designed for the job. It's very tough (and will easily withstand being dropped off a high ladder onto concrete), hard to lose (the yellow colour isn't just for show!) and works well.