@UnWired 

Needing to jump either circuits or phases will affect performance. If your current application is that you are fine with the speeds it might be best to leave it as is.

@Tony 

Thanks for responding.   Never one to "leave well enough alone", I did march down to the electric panel and switch a couple of circuit breakers to get both Powerline circuits on the same phase.  As far as I can tell, any difference is negligable.  Observing the reported transmit speeds on the tlPLC utility, speeds change with every report, sometimes dramatically.  A link can report 40mb and then 90mb a few seconds later.  It can report 70mb in one direction, but 160mb in the return direction.

I started all this because I have four IP security cameras in one corner of the house that are connected to a PoE switch in the garage.  Every couple of months, the PA9020 in the garage "goes red" and I have to reset and reconnect it.  The cameras have SD cards in them, but I also have them FTPing motion recordings and when the link goes down, I get no recordings until I wander into the garage and notice, "damn.  down again."

I had hoped that putting both circuits on the same phase would (1) increase the speed and (2) keep that unit from losing connection.  (sigh) another fail.

@UnWired If your house wiring is any reasonably code adherent system, it shouldn't matter which phase the EOP devices are on. Usually they can make the crossover, but if they don't, there's a workaround using a capacitor (don't remember value...someone jump in here if you know) to bridge the two phases. It has to be a pretty ancient system, all the way out to the transformer on the street feeding you 240 two phase for it not to work right away..

@CaribConsult 

Thanks for the hint. Now that my PA's are all on the same phase, the question is not as urgent.

However, it has caused me to think about the question in a different way.

From what I read, flourescent and LED lighting often creates electrical noise.  With incandescent bulbs no longer being sold, my house is almost 100% LED lighting.

How do I prevent lighting circuits from impacting Powerline adapters?

I have asked (on a different thread) if it would make any sense to put ferrite cores in the electrical panel on the hot, neutral, and ground wires for the "non Powerline" circuits.  3mm cores are inexpensive (supposing I can find 3mm cores of "mix 31" material).

Or, is time/money better spent eliminating electrial noise that is physically close to Powerline Adapters?