Thanks very much for your comments.
I already phoned my ISP. It said that this was an Apple AE problem. (The usual pass it on -- "it's not us to blame".) I I phoned it again and asked for a senior person. But he said that they could do nothing. It would be different if I could not send or receive.
You realize from my post that I do not have at the cottage a router. My set up at the lake is not common in cities but is now common in rural areas. There is a nearby sending tower and on the residence structure there is an antenna or a dish that receives signals from the tower and sends signals to the tower. The unmanned tower is the router. The line from the antenna/dish plugs DIRECTLY into the computer or if one wants WIFI plugs DIRECTLY into the WAN port of AE.
I have a guess as to the problem. The problem started just recently. Just recently my son, who has a cottage on nearby land that I gave him, took up with my ISP. We might have the same IP address? Is that even possible? I'll have to walk over to see if I can find out his IP address.
If I unplug the antenna/dish line from the AE and then replug, no flashing orange light for maybe several hours of use. Does not help to restart the iMac or iPad.
Does not to help if i turn off WIFI on my iMac and use Ethernet. AE still blinks yellow and the iPad (only) still gets Airport Utility pop-ups
