I don't know a lot about RF transmitters. What do you think of this one?
https://www.amazon.com/Adjustable-Broadcast-Transmitter-conference-christmas/dp/B075DC75HX/ref=pd_sbs_107_14?_encoding=UTF8&pd_rd_i=B07194M2Z6&pd_rd_r=EG4DCG9BBJPM9EQECDTH&pd_rd_w=5lsgA&pd_rd_wg=BGjCu&refRID=EG4DCG9BBJPM9EQECDTH&th=1