Make sure you have the antennas at 90 degrees to each other. 2.4GHz is very prone to polarization problems and keeping the antennas 90 deg. apart greatly reduces the chance of losing signal due to reflected and blocked RF. I have one antenna going straight back, zip-tied to one of my tail support struts and the other one goes down the landing gear. This setup has worked very well for me (no glitches and/or lock-outs in about a year of flying almost daily).

I am not sure if the DX7 has the same silly linear regulator for the 3.3v section that the DX6 has, but here is the info for the DX6. My DX6 is now the energizer bunny of transmitters after this fix!

[link=http://www.dimensionengineering.com/appnotes/spektrum_mod/spektrum_mod.htm]DX6 Regulator Upgrade[/link]

Steve