I have one of mine on the curtain rail using a cheap clip and the other screwed in the wall above the door. They are at different heights and work fine. I believe as long as they can see each other it wont matter (which is naturally more likely at 6'5''+).
If you have one at desk height then surely its view to the other will be blocked at times which would mean you would need the sync cable attached instead. Of course if you already using it then it could be just vibrations as mentioned.
If you have one at desk height then surely its view to the other will be blocked at times which would mean you would need the sync cable attached instead. Of course if you already using it then it could be just vibrations as mentioned.