Ghost Power

It doesn't make any sense to be able to pick up a receipt of a general signal (that signal MUST have been general, because they didn't know where to send it, of course!)

And if it was that simple the Trade Federation could have found her.

off-topic now.

Even with the reshooting, the name Lian Neeson is not with them...

Maul might have calculated the route to take after their escape from Naboo. He simply put himself in their position and came up with the same planet.

Indeed, I have always been amenable to the idea that good detective work and, of course, Force-based instinct allowed Maul to find them.

However:

1. Sidiuous and Maul clearly refer to a 'trace' on Coruscant

2. It doesn't really matter; like I say, you can come up with all sorts of ways to explain it, bit it wasn't explained in the film, which was an omission.