Home Internet - Sudden consistent signal degradation

As far as mysteries go with speed changes, I have one that is even stranger. I'm on the same signal pair (B2/n41) with the same signal strength as I started out with but my average speed went from 90 1o 190 one morning. For the first two months my peak speed was 190, and recently I hit 420.  

If I had your problem, a signal drop like that, I'd suspect I might be on another tower. Or, they adjusted the fan pattern of transmission in a way that it degraded the signal to your house. Another reason could be they turned down the transmission power on your tower. They might do that when they have a conflict with another carrier's signal.

While I haven't read of a person having a gateway performance issue like your particular problem needing a new gateway, that's something you could probably consider. But call first and see if maybe they know they are doing work on your tower, in which case no need to go through the fuss of trying a new gateway.

Since there’s a possibility you are on another tower. if let’s say they are doing maintenance on your old tower, you should try a different location/orientation for your gateway, if you haven’t already.

When I got my speed boost, I thought some new gateway location/orientation experimentation was warranted to optimize it, and it did.

I started a thread on the 1609 firmware update and no one has reported that issue, nor has the firmware ever done something to a person's signal strength that I'm aware of. I got my speed boost a week before I got the 1609 firmware update.