PPB has moved all Central dispatch traffic to C Tac 1 (an encrypted talkgroup) since the start of the 2020 protests. There's a good chance you'll only hear PSU Police.
Dedicated computer using dual RTL-SDRs and DSD+ software to monitor Portland P25 talkgroups 467 (PPB Central Dispatch) and 1691 (PSU PD) Receiver is set so that PPB transmissions should always take priority over PSU transmissions.
(Audio "glitches" are caused by imperfect decoding of this newer digital P25 signal, fine-tuning it is a never ending work in progress.) With this setup I can stream any talkgroup on the Portland P25 system. If you have something you'd like to hear, send me a message. If there's a consensus, I'd consider adding another feed. <3