To my mind it really doesn't matter if the drone transmits for 30 minutes or 3 minutes, because finding an electronic signal only takes a Complex Action, assuming someone is looking. Given that this seems to be a moderately secure setup run by professionals, it's a safe bet that someone is indeed looking.
In other words, the length of the transmission doesn't matter as long as it is more than a couple Combat Turn long, because Shadowun is a game of abstractions. If we assume that both SpitFire and the opponents are moderately good or better at their jobs, the opponents will get at least one chance to spot the drone. One Matrix Perception test which, if successful, is followed by a at least one Brute Force/Hack on the Fly action to get the necessary 2 MARKs for a Trace Icon test, and Bob's your uncle.
Assuming the opponent can get three actions in one Combat Turn we're looking at a worst case scenario of 3 seconds to spot and trace the icon, possibly without SpitFire ever knowing. Worst case he's only got one action per combat turn, in which case you're looking at a best case time frame (assuming he succeeds on all rolls of course) of 4 Combat Turns, or 12 seconds. There are obviously a lot of things that can go wrong; if the drone isn't running silently then it's just a simple "show me all devices within 100m", or even a "show me all devices within 100m that are not door locks or security cameras" and the game is pretty much up.
This one really comes down to the GM; to my mind this could be as simple as a sneaking test if they don't have matrix support on site; can they spot the drone (with a negative dice pool modifier for size and possibly for not specifically looking) against the drone's Sneaking roll. If they do have Matrix Perception, can they even spot the drone's icon on the Matrix? If yes, then it might be worth making some actual rolls against it.
ETA:
All of the above being said, data sizes are specifically called out in the core book as being mostly insignificant due to improvements in technology. So the 30 minute download time is rather jarring to me; I could accept it needing to perform several steps to use the new software, but strictly speaking this should only take 1 Complex Action for Edit File to copy it from the Matrix (or RCC, wherever SpitFire chooses to keep it), and another Complex Action to load a stored program or swap a running program for a loaded one, for a total time of less than 3 seconds.
Again, as per the above the time of it all doesn't really matter as even remaining online for 3 seconds is enough for a good decker to spot the drone, and because Shadowrun is abstracted we won't make one roll for every period of time the drone is online, instead we'll roll once for the entire duration. At least, that's how the game is designed, similar to how you would make one Sneaking check even if 4 different guards got a chance to spot you on an approach.
Of course, you could roll once for every hour but that gets tedious real quick, so I personally prefer the more abstract method.