I also facing slow BT download < 10kB/s since one week ago eventhough signal strength 100%.
I am using Izzi One package with antenna. Location Selayang baru.
According to Izzi customer service, they start to control BT usage like other ISPs.

Jeff, nothing related to you PC or antenna otr router issue.

BTW, FYI my BT download speed can reach 100kB/s if using Streamyx 1MB..