Interesting problem.it seems that the remote frequency used by the the 9241 interferes with the X10 system that I use to control all of the lights in my bedroom
Do you know what the exact frequencies in use for both are?
if this is the system your referring to saw this wiki entry
Seems like X10 might be around 310 MHz for the remote itself, and 120 KHz for the signalling between X10 interfaces.
Couldn't find much about the dish remote, other than what u probably already know.
Not clear though whether ur issue is related to the various X10 boxes ur using interconnecting via the AC Line? Or if it's a radio related problem between the two remotes? Like I can't imagine the satellite remote actually transmitting anything, unless your pressing a button, so what's there to cause interference? I'm inclined to suspect something in the DISH receiver's power supply (likely a switched mode power supply, emitting trash) is distorting the 120 KHz digital signals that ride the AC Power Line wiring which allow the X10 interfaces to communicate.
Have ya contacted the X10 system customer support to see if they could offer some advice? Maybe they've come across this before and have a simple solution? Something like an AC Line EMI Filter to plug the Dish receiver into to help isolate it? Do you know if the electrician tried using one?
edit: note on flipping to legacy remote:
. All secondary remotes for dual tuners may also be converted to remote #1 by flipping the plastic bottom of the remote. This also switches its transmission mode from UHF Pro to regular UHF and IR, similar to how a 5900 remote operates.