RE: Spectrum with "giant scale"
I was running the DX-7 on 5 different airplanes from 25% to 35% all gassers. I had 100 flights - all but 3 were touble free.
My transmitter died and has gone back to Horizon so I am back on 72MHz now.
Here are my comments:
1. Be sure you use redundant batteries and a power system of some kind as the Rx is sensative to power drops
2. Don't point the antenna at the airplane - same as 72MHz this greatly reduces the signal
3. We have had several (i.e. 5 that I know of) transmitters die at our club. The normal symptom is when they are turned on the screen fades in and out and then the radio simply "dies." None have died in flight but no one feels too comfortable about them any more. The LHS has simply replaced them with new ones for the most part (I sent mine back to find out what was wrong with it.) Just prior to mine dying I had 3 flights with some weird slow response/mushy feeling in the controls. Not a technology issue - this could happen on an radio and any system (72mhz, 5mhz, 50mhz, cheap, expensive, whatever.)
4. Because of the voltage issues with the Rx be careful in electric planes using a BEC. I have seen several small 480 sized park flyer airplanes re-boot the Rx during hard acceleration on up lines.
If you do #1 and #2 above then you should have no problems. The system is fast, feels locked in and solid when everything is working. It is basicaly immune to RF interferance from the ignition and airframe which makes setup a breeze too.