FM or PCM?
It's called harmonics not images. It's unavoidable in the RF world, you can help reduce it, but it can NEVER be eliminated (The only way to have a 0 harmonic wave form is to have a perfect sine wave) A perfect sine wave carries no data. I wish more companies did have good design practices. Just think of the cost of a modern day cell phone. Think of how many channels are crowded on their bandwidth and how well (considering traffic) they perform. R/C equipment manufactures are out to make a buck, not break new ground in functionality. Or we'd all have high speed bidirectional data links to whatever you fly. They keep just enough innovation in the market to keep people buying new products. (With a few exceptions) Then again the markets tough too, so it's hard to blame just corporate America.