@Tony 

Thanks for letting me know.  My guess is the testers have more than the Holiday on their minds right now. (virus killing people!)

After a couple of days of working fine, it's back to the "flashing red" and reporting "?" in all directions.  I'll reset it again.

I went with Powerline because it was "so easy" and was "so fast".  And worked like gangbusters for months andmonths.  Heck, 50mb would be great, except that when it "goes red", my IP cameras simply won't stream and can't FTP.  I am (literally) desperate for a solution besides climbing through the attic and penetrating fire-rated walls to pull ethernet cable.  If it's simply distance, then it shouldn't work from the start.  If it's something that V3 adapters do better than V1, I'll replace them.  I will happily buy a fist full of noise reducing gizmos and isolate every motor and appliance in the house.  But, no one can suggest "what works".

That's what confounds me.  Reset the adapter, and I'm good for days. Then, I'm "red".

You are very patient.  Thanks.

@UnWired 

Just checking in.  The news reports the holiday is over, what there was of it.  Have improved my Powerline network with the addition of EMI filters and ferrite cores, but still wondering how to understand/manage the tpPLC Utility.

In addition to the question of "What the Heck is Going On when I add a fifth adapter?", I now have another question:

My four Powerline adapters are arranged in a line.  #1 -> #2 -> electric panel -> #3 -> #4

tpPLC reports the transmission rate declines with distance (as it should).  Looking at #1, the rate is highest to #2, then #3, and lowest to #4.

BUT, looking from the other end, it is #4 to #3 (highest), #4 to #1 next, #4 to #2 lowest.  (not by much, but how is this possible?)

@UnWired 

Because the reported transmission/reception rates vary so much over time, it would be really useful to be able to collect them into a file for analysis.

Seems like that would be sort of an obvious feature to have in the tpPLC Utility.  The source code is probably a "Trade Secret", or I'd offer to modify the code myself.  (Or is it?  Isn't every company's Powerline utility program based on code from Qualcomm?)

I can capture the ethernet packets between tpPLC and the adapters, but they appear to be encrypted.  Perhaps someone can share how they are encrypted?  Like, maybe using the unique codes written on the label of each adapter?

@UnWired 

Here is a general tips guide for reference on ways to improve performance: https://www.tp-link.com/us/support/faq/409/

If a powerline device is turning red, try and change the location or even swap adapters to see if it follows the adapter or stays with the location. It pretty much comes down to the location as there may be electrical interference happening causing the speed to drop below 50 Mbps. To test to see if powerline devices are bad, you could plug them in the same room or have them as close as possible to see if they stay green.

I know that in the powerline network one powerline is designated as the device that controls the speed which is usually the first device that is plugged in. You can possibly look to use that to designate another device as the main hub to see if you see a difference in performance.

I inquired again about verifying the question marks in the tpPLC apps.

@Tony 

You are really kind to follow up on this.  The FAQ is helpful.  I wish it were more "technical".  For example:

• The advice to plug appliances into a surge protector.  What kind of surge protector?  I'm assuming that a device that is "nearby" but is on a different electrical circuit is not relevant, or is it?

• The same issue applies to electronic power supplies (cell phone chargers, computers, etc.)  Things on other circuits are relevant (or not)?

Now that I have made a bunch of changes, I will get out my new PA-9020's and try installing a couple more and see what the tpPLC Utility does.

@UnWired 

Added one V3 PA9020 to the existing four, and the same problem happens immediately.  The "base unit" reports transmission speed to the other four (3 old plus 1 new), but every remote adapter reports speed only to the base.  To other adapters it reports "?".  Thinking, "Maybe it takes time to settle down." So, I left it alone for several hours.  Nope.  Same behavior. "?"  Back in the box it went.