boston police

I live in Dorchester but no matter what scanner and antenna I use BPD Ch 5 is weak, heavy static, and is practically unlistenable. No other BPD channel gives me issues. Thoughts?

While scanning the Boston Police Department a few days ago ( I listen to A-1 and A-7 ) there was an ALL OUT broadcast on all stations calling for all "EDTs" to report to a crime scene in Mattapan. A-1 had two officers who were EDT's and A-7 also had two. I have no clue what it means.. not one...