ORIGINAL: rmh
Based on your comments - it isn't the equipment which is the issue
Unfortunately you have apparantly convinced yourself that the equipment is the issue.
FWIW - the old ''two minutes into the flight comment is a classic - which indictes all is well until power runs out
I have setup way over one hundred of these Spektrum models - some for other fliers
No problems such as you note.
Whomever your expert is - you might do well to start over with someone who really understand power setups and rx application and positioning - .
And he can get another brand radio and no longer worry about receivers ultra sensitive to voltage, need for satellite receivers, tricky positioning of components, BNF stuff that has a high failure rate within a few flights (ask my local HS), tech support saying you didn't hold your tongue right, etc.
Certainly some modelers do themselves harm but when long time, very experienced modelers suffer the same mysterious Spektrum failures it generates many questions..