It is just inconsistent. Everything in the environment can impact a wireless connection. It is simply the nature of hte beast.
I work in the IT periphery world, and unfortunately wireless is not always the answer. It is great in some applications, but the transfer of data is VERY susceptible to interference. Something as simple as a wireless RF (Radio Frequency) telephone set can cause the complete shutdown of wireless communications.
We did an installation of wireless microphones in a banquet area during the winter, everything was working great for about 6 months. Then we get a call saying NONE of the mics are working. Thinking primarily that the failure must be due to a power surge of some kind we took the system down and tested it in our shop... Everything worked as expected.

So we then took the system back to the installation and NOTHING worked.
Long story short, we realized that on the roof top of our installation area were 3 industrial sized air conditioning units that were throwing a TONNE of Radio Frequency & Electromagnetic Interference (during hot summer days) which completely destroyed the data being carried on our wireless microphone frequencies. Moral of the story, where possible, a physical connection is optimal for data transfer.
