2) Are those dropouts happening at repeated 'cyclic' intervals?
It seems like it happens during the day from late morning to late afternoon. TYPICALLY. The time varies as far as how long it is dropped out, but that's about all I can predict.
3) Does the power meter at your house 'automatically' transmit data back to the power company?
I do have a new power meter, so I am guessing it does. I thought Zigbee was a 2.4Ghz frequency. That said, the meter itself is on the exact opposite side of the house.
Some smart meters use the 900MHz band. I have one and don't have any problem with the multiple Davis transmitters and receivers. See
this for more details on RF from the smart meters.
I have a Davis long range repeater that I use to receive the ISS signals from the local marina which is 2000 ft. (610m) away. I had a lot of interference issues that I eventually solved with a band-pass filter. I realize that this is not helpful in terms of a standard ISS-to-console communication configuration. When I was troubleshooting the problem, I used an "RF Explorer" and I could see strong interference in the 750MHz and 850MHz areas. The county communications tower for the Sheriff department is a few blocks away and I suspect that some of this is the 800MHz band that they use.
While it does cost some money, I found the RF Explorer particularly useful in hunting down these kind of problems. I have the most basic model, which is fine for this purpose.
http://rfexplorer.com/models/ The peak modes are good at viewing the Davis transmissions. I was able to see broadband interference when I expanded the range to include the 750-850MHz bands.
Greg H.