Canon 600EX II-RT drops link- HELP!

[Phillyphoto]

Scenarios I have tried: 

Using Canon Transmitter ST-E3-RT as the master and (2) 600 EX II-RTs as slaves.

Using A 600EX as master and B 600EX as slave.

Using B 600EX as master and A 600EX as slave. 

I get the same result of the slave dropping link. The time varies. Sometimes it drops link in 4 mins, sometimes 10mins, sometimes 20 or more minutes. The only way to relink them is by turning everything off and back on.

All channels are the same. Yes, I have scanned for the best connection as well as every other channel and AUTO.

All IDs are the same. 

Not near a wifi-router or airport, I'm in a row home in Philadelphia. 

Using NiMh rechargeables and using freshly charged batteries for every test. Batteries are about 2 years old. 

I have spoken to 2 Canon service reps and neither of them has any idea what the problem is. I really don't have the money to spend on sending everything in for "repair". 

Any help is greatly appreciated, thanks!

[BillWayToday]

I have now built a continuous light setup for the studio at home and my FIVE Canon flashes are consigned to the unlikely prospect of environmental photo's elsewhere (where the EMI is hopefully less).  As a 100% Canon user with thousands of dollars in Canon gear, I've gotta tell you this is incredibly disappointing.  

[tseager]

I hear you. It must be some terrible secret Canon doesn't want to address publicly. 21 pages on this thread alone isn't indication enough for Canon? For Cannon support to continually say they have never heard of the issue? Hmmm.

I tried all the suggestions and was unsuccessful, and came to the same conclusion you did.

Shifting to another lighting system and modifiers was expensive and time consuming. On my way to purchase Westcott gear, I loaded all my Canon flashes in the car, turned them on, and had them on the seat as I drove. Not one failure for over 2 hours of driving. At home, they don't last 5 minutes. That's why I suspect it's EMI interference with new WiFI systems.

I don't use artificial lighting on the go, so I sadly let go of all my Canon units. They did work well for a couple years.

[Nick55]

Oh Canon knows. They just don’t care to look for a solution as all current models have the dreaded “Link Drop”