RBK 40 Internet speed issue

Thanks for your input. I decided to call Spectrum as the speed tests repeated on one device were varying a lot. They suggested changing from Ch 9 on 2.4 GHZ to channel 1, which I did. My call to them resulted in a service call scheduled for tomorrow. The firmware is up to date (V2.3.5.30). My satellite units are about 30 feet away from the main router. The ISP modem is an Aaris TM 1602. Home size is about 3200 s.f. (3 levels - main, upper and basement levels - the satellites are on the main level and in the basement). If there are WiFi neighbors, none are closer than 300 feet (only 1 at that short a distance). Right now, Daisy Chain, Fast Roaming, WMM and Beamforming are all enabled, and MU-MIMO and 20/40 MHz Coexistence are not enabled. Until Spectrum has completed their service call, I will not try any new adjustments - there's too much signal noise. I really appreciate the prompt response, David