Reception problems

What is the deal with the 100 series (and occasionally other channels) reception?  The sound quits or is very chopped up, the picture freezes or goes into heavy pixelation mode and sometimes the channel is completely dropped.  Happens for awhile and then stops.  Then it starts again.  No pattern or predictability.  I've reset the box and had service out - no issues.  Very irritating and I've missed more than one show.

Also - these so-called Emergency Broadcast messages that are supposed to be "monthly".  They aren't.  I've had them two days in a row, several times in a month etc.

I am in Topeka...