Controller works sometimes, sometimes not

[Donl1150]

My scaled down show this year has 4 - CTB16 AC controllers.  Half of the show is on one side of the house, the other half on the opposite side.  I have Controller 1 on one side and the other three on the other side.  I am using ELL's to get the signal to both sides of the house.  All are on Channel 16.  The 3 on that side of of house has 2 receiving ELL's thus only 2 controllers are daisy chained - units 3 & 4.s

The HU finds all four units and all circuits work properly.

The problem is when running the Show, controller 1 sometimes works - sometimes not.  Sometimes in the middle of the show it decides to shut down.

Oh.... my show is simply an animation with no music.  A 5 minute show consisting of a single sequence that loops continuously.

Any ides what could be causing it?

[TheDucks]

Don't put the master ELL (the one connected to the computer) inside the building. 900MHz is easily blocked by metal or masonry.

Sheltered on a open porch or under the eves is usually fine.  This frequency is mostly line of sight