430ex iii-RT - Multiple flashes won't stay linked/synced

[ajlockwood]

This problem has recently developed.  I use 9 430ex iii-rt's at the same time, one as a master and the others as slaves.  I use 4 on A and 4 on B and 1 for the master.  The master is set to the Manual mode.  All the units, slaves and masters are set to the same frequency and channel.  They use to stay synced for easily an hour or two with no problems.  Lately, after about 5 minutes (sometimes as few as 2 and sometimes as long as ten), the slaves delink and show a red indicator despite the master still showing green.  It does not matter which unit is used as the master.  I've tried several combinations, and the units will no longer stay linked.  I've tried using different frequencies.  Same problem.  It does not matter which camera I use.  Same problem.  Batteries are freshly charged ... same problem.  I shoot all canon cameras that are compatible with the flashes (5DSR and 1DX).  Same problem.  Even if not mounted on any cameras ... same problem.  Any help with this problem is appreciated.  Basically, the units are worthless in a shoot if they keep losing the signal from the master.  Thanks for any help.

[Kelly93]

Just bought the STS-ET-R3 and 430ex rt iiiI, previously had a couple 600ex rts (v1) with the STS-ET-R3 and I had zero issues.  Well, i could not get the new flash and controller to stay synched.  Same channel and ID on both, would sync initially, but would lose sync right next to each other after a handful of shots.  Checked for interference, none.  Changed channel and ID (still a low number), same thing.  

Read the above post… channel 15 and ID 9999, problem solved.  Kind of weird, but happy i found the post above before i spent more time on it.

[ajlockwood · Accepted solution]

After several tests and retries, the issue is clearly that you just need to find a channel and ID that works without interference.  The ID number should use all the same digits, ie. 9999, 8888, 7777 etc.  I used the STS-ET-R3 (version II)  transmitter and eight 430ex RT IIIs.  If the transmitter went to sleep, the flashes delinked, but properly relinked when waking up the transmitter.  At times during the test (which was for an hour), I could see a flash delink and then relink on its own, even when the transmitter was awake.  This is likely due to interference, but again, it properly relinked on its own.  It was not always the same flash that delinked and relinked.  To summarize again, the solution is to find a channel and ID that work for you.  Try and find a couple/three that work, because it is likely it won't always be the same one.  Thank you to everyone who helped contribute to this discussion.