I just wanted to post a note of thanks to those that have directly or indirectly helped me and also share my fix in case anyone else has the same problem. I have a MX-850 and MRF-300/RFX-150 that I bought in Spring 2005. It has worked pretty well but about 25% of the time the commands wouldn't work and even less on my DVD player. The remote would always work 100% IR. Which lead me down the RF route. I first tried moving the RFX-150 closer to my seating position and it seemed to help some. I then tried the ferrite core trick on the flasher for the DVD and it didn't seem to do much. I found that it appeared my DVD player was causing interference since all the problems went away when I turned it off, but later that seemed to be untrue.

Yesterday I tried using the RFX-150 to see if there was any interference. No matter what setting I had the gain adjustment on there was never even a hint of interference according to LED. I decided to turn the gain all the way down. I also added ferrite cores to both ends of the RFX-150 power/singal cord, each wrapped multiple times around. I am not 100% sure if one or the other or both together did it but the control is more reliable than ever now. I finally feel like it is working right. I don't want to try to get the cores back out of the wiring to see if they make a difference or not.

I am also happy I found this solution without trying a MRF-350 and possibly a new MX-850. Anyway thanks again and good luck to anyone having similar RF issues.