I have some wireless named frequencies, which seem to be turning off by themselves sometimes (the receiver doesn't light up, the transmitter is lit up properly), mostly when I go to nether and back (having signal always enabled), most likely 100% reproduced if transmitter is in nether and receiver is in overworld (especially if the receiver is in subchunks near to the portal). This doesn't seem to be the only time when this happens, but it is the most easy way to reproduce. Turning redstone on/off doesn't seem to help here, I need to change the frequency on the receiver (and change it back), then the receiver lights up. Also I have "!" in the frequency name, if that matters.

Same problem for me.

It's the same thing at home, it happens generaly, as soon as I disconnect me more than 5 min, I also have to change the frequency on the receiver or break it and replace a new

Same, i have wireless railroad crossings and sometimes the reciever needs to be replaced, wich is a problem, because believe it or not, railroad crossings are quite important on a world with automatic trains and personal car transport mods.

I am also having a problem with the Wireless Receivers not lighting up and losing thier frequencies. I am using them to activate redstone lamps in my grinders.
The Wireless Transmitters for each set are close by. But I have noticed that when I log on in the morning or even possibly when I leave the dimention and come back, some of the Receivers are not working. I am playing FTB Infinity Evolved for Minecraft version 1.7.10.
Yes, the sets have thier own frequency.
Yes, I have double checked that the are set to the right frequency.
Yes, I have tried deleting the RedstoneEther folder for that dimention.