I agree with logger, for the reasons he outlined. Camera has to talk to both router and sync module. Theoretically the camera has a 100 foot range to both, so not much to be gained by moving the sync module nearer, if you are working at the limits, because you will also be at the limit of camera to WiFi.
I say theoretically, because in practice, I found that the module does not have quite the same range that the camera to WiFi does, so in one particular spot, where I am really pushing the limits, for reliable operation, I benefited by tweaking the sync module position a little nearer to one camera than the router. This left the sync module easily close enough to the router, only 15 feet away, but 15 feet nearer to the camera than the router, which was just enough to get a good result, not least because in this new spot there was line of sight from the sync module to the camera, directly through a window. Camera to router is through a wall, but for WiFi this seems to work okay.
For one camera, which is way too far away from my router, and too many walls, I have used another sync module, and it picks its WiFi up from an Ethernet wired WiFi extender. For this location, I have the sync module practically on top of this extender.