Had a very strange RF problem at a clients home last week.
The system : Denon AVR2106, Comcast High def box (not dvr), Directv HR10-250, Sony DVP NC665, Pioneer PDP505cmx and an MX850.

When we first set up the system without the plasma or the sat receiver, we used a MRF 250 for the RF system and had some issues with the range and command reliablity, but we adjusted the location of the MRF and got the performance up to acceptable for the client.

We came back last week and added the plasma and the Directv dvr and of course the RF interference came back with a vengence.

We switched to a MRF 300 and turned down the levels on the Directv flasher and moved the antenna away from the system and lowered the sensitivity on it as well.
The control was finally working fairly well in RF mode for the problem devices and was about to wrap up when I tried the Sony DVD. No go, no control at all. I double checked the codes and the ir flasher connection. I switched the remote to IR only and found the codes worked perfectly.

The MRF 300 is set on 0 to minimize problems with the Denon AVR2106 but I've never seen control problems like this. Any Ideas?

First of all, setting your Base to ID0 is really a bad idea. It opens the receiver to receive ALL interefereance. It's a test mode only. You really need to set it to a number. I think that'll reduce your problems immensly. Also, if you need to reduce RF reception further, a good way to do it is take the antenna off the RFX 150 included with the MRF300.

Is taking off the antenna similar to turning the sensitivity all the way down or does it have a different result? like stronger reception but better interference rejection..

I agree on setting the base to 0 is a bad idea but right now it's the only way to make the Denon receiver work smoothly.

Taking the antenna off will have a different effect. I have done this many times on the MRF 250 and it worked great afterwards. Some components will not operate if there is any RF interference at all. I have experienced this with many different components and I would suspect the Sony is one of these.

Basically, (the way I understand it) it severs the RF reception way down, which cuts the remotes usable distance down, but also cuts the RF interference way down as well. Overall, if you're not trying to use it from 100 Ft away, it will be inconsequential to the end user.

A lot of people believe that ID0 opens the MRF up to more interference, actually the only thing ID0 does is light the status light when it receives RF in it's range to US a problem (and of course defeats IR routing and the blaster). The MRF will be NO less prone to interference when set to a different ID you just won't have any indication of the interference unless you see the status light stay on for a bit after you release a button (a definite indication of interference).

The biggest reason it is a bad idea to leave an MRF on 0 is because if you have any neighbors with a URC (or multiple remotes in the house) their commands will be received and executed by that MRF.

I understand in this case it's because of the Denon, but changing it to a different ID shouldn't help anyway.

I don't want to insult you, but are you 100% positive of the emitter placement? Can you see the receiving eye with a flashlight? (NEVER trust those little IR symbols the eye can be anywhere)
Is the emitter flashing?

Go ahead insult me, I don't mind. Yes I did make sure of the emitter placement.(and all the flashers are flashing.no routing)
Next time I'm over at the job I'll try dropping the reception on the antenna to zero and see what that does. But are you saying to remove the antenna off the RFX150? dialing down the sensitivity isn't enough?
I may end up switching the customer over to an IR repeater.

First dial the antenna all the way down and see what happens. I've had a many jobs where the leaving the antenna set where it comes out of the box is too high and some components won't work. Then you can try removing the antenna from the RFX-150.

I realize the ID has to be left on 0, but if you're the cuious type like I am try setting up the routing and set the ID to something other than 0 and see if the DVD comes around.

Sony is usually really good about not overloading, but without routing I suppose it could be overloading, maybe you could mask some of the stray IR with a niles IR blocker (or equivelant) so even though all flashers are flashing the DVD would only see what was coming from it's flasher.

Also, if it is overloading, try unplugging the IR emitter for the DVD and see if the flooding from the other emitters will operate it.

Just a few ideas... keep us posted

Well, try dialing down the sensitivity first. If that still is unreliable, phsically take the antenna off the 150. It's sandwiched between two copper washers, so don't lose those, in case you need to put it back on.

Thanks for all the ideas. Maybe we can tell our war stories over refreshments at CEDIA-Eric better be buying the first round.