« on: September 28, 2013, 12:56:12 AM »
People should keep in mind that this equipment operates in the 2405 MHz-2475 MHz microwave band, the same place where a lot of other stuff operates including, all sorts of wireless devices as well as the worst offender for RFI which is the old trusty microwave oven.
This thread got my curiosity up and I put one of my 600EX-RT's in the kitchen about ten feet from my microwave oven, and fired my ST-E3 in the living room (about 15 FT from the flash). The result is that it works fine with the microwave off but cannot communicate when the microwave is on -- link lite went out and everything. I have noticed in the past that when my wife runs the microwave my Apple TV and Laptop also loose wireless communication so upon seeing this thread, I thought I'd try the Canon flashes -- yep, sure enough the pesky microwave fouls them up as well.
Perusing the ST-E3 manual, it looks like the Canon system is using the same sort of signaling as IEEE 802.11 b/g (Direct Sequence Spread Spectrum, Offset QPSK) in the 2.4 GHz wireless band.
Like some of the others here, I would put my money on RFI rather than the ST-E3 overheating (I have used mine a lot and never seen an overheat issue). I think my kitchen microwave is worse than some others, one of my work buddies when hearing my story was surprised since he said he never had issues running his laptop near his.
People with Canon Radio systems should run some experiments. I gaffer taped my iPhone 5 to the same 600EX-RT and didn't have an issue. It seems to fire nicely when located right next to my router as well. So maybe it needs something real strong like a microwave oven to wipe it out. It may be worth some testing for those who are interested in such things.