Unfortunately the only way to stop this from happening is to separate the receiver boxes.
The Slingbox 500 is functioning normally, as it is sending out a signal with the Internal IR Emitter and is getting picked up by both DirecTV receiver boxes.
So if you do not want this to happen you will have to find away to block the signal being sent. But in the way you describe that you have the DirecTV receiver boxes, you will have to place the boxes in a different room or take one box out of the cabinet.
Hope this helps!!!
Sling Media Moderation Team
Theoretically it should be possible to change the (infrared) remote ID that the non-Sling receiver is using. Think of the situation in a bar where there is a bank of DirecTV receivers--the owner of the establishment can't have all the receivers respond to a single remote.
The best solution--call DirecTV, explain you have two receivers in the same room and they're responding to a single remote's commands (do NOT mention the Slingbox, it distracts from the solution which is Slingbox-independent). Ask DirecTV for assistance changing the remote ID and receiver remote ID on the non-Slingbox receiver (why the non-Slingbox receiver? You already have the Slingbox's virtual remote control working--why mess with it further?).
This will only work if there was no other Slingbox connected. karalic has two Slingboxes connected in the same area and the Slingbox 500 is changing channels on both receivers.
If karalic called DirecTV to change the IR settings to RF ( for an example ) then karalic will lose the functionality of one of the Slingboxes due to the Slingbox only works with IR sensors.
Again, the only solution to karalic problem is to either remove one DirecTV receiver to a different room or to block the signal in some way.
There are additional remote control options that might work--under the remotes for Satellite -> DirecTV:
D10 (Remote Address 2)
Remote Address 1
Remote Address 2
Remote Address 3
Remote Address 4
Possibly one of these alternates might work? Although there's no specific "second address" remote in Sling's database for the Genie/Genie Mini remote, the "second address" entry for the previous white DirecTV remote could be an option.
Yes, I think Kevin is incorrect, this is an easy fix. The procedure to change a remote address for one of the DirecTV boxes should be covered in the manual (menu> setup> settings> remote ?). It defaults to 1 but can be set anywhere between 1-8. A lot of users on this forum have changed them.
The Slingbox remote defaults to Address 1, but as ferguspa points out, all DirecTV boxes use the same set of codes and there are a number of Slingbox remote controls that use the other addresses. Failing that I have produced Custom Remotes for all 8 possible addresses at DirecTV Remotes for Addresses 1-8