Hmm, then you need a super-mega-amplifier tacked on to boost the signal over the cable (AFAIK, the frequencies used really like short antenna runs).
So that then means a super-thick faraday cage around the actual device, and probably somewhat noteworthy power consumption (a battery certainly wouldn't be enough).
Probably meant transmitter (antennae + encoder/decoder) separated from actual BTS hardware & operatives.
So after counter-side finds your camouflaged BTS, it is only disposable and relatively cheap part and doesn’t lead to whole operation uncover.
That probe part then would connect to starbucks wi-fi and interact with BTS software somewhere far from physical location, so you can’t quickly trace channel between probe and spy team.
So that then means a super-thick faraday cage around the actual device, and probably somewhat noteworthy power consumption (a battery certainly wouldn't be enough).