Installing a signal transmitter on the roof of a residential building without permission ... seeking legal advice ...

That's what the property allows them to install. If it is to be demolished, it is useless to complain directly to the property. You must complain to the owners' committee and ask the owners' committee to demolish the property. But now there are no owners' committees in many communities, and many owners are indifferent to these, only when they infringe on their own interests. Ask if there is an owners' committee. As long as the Committee votes, it can demand the demolition of the property.

Finally, it is to directly request the court to dismantle it through litigation, but this is very complicated, and you have to bear the burden of proof, including the assessment report that the signal tower is harmful to the human body.