When I found I could no longer get the 7800n, I decided to try the 7800NXL, and it arrived last Sunday, easy to set up, and works very well.
But, we found that only some wireless items were picked up, others not.
Today, looking through the advanced wireless settings, I noticed the channel setting. It was on 6, and in brackets next to it was '(interference - high)'
I don't know much about wireless settings and channels, but did recall something about channel 11, so set it on that, and now get: '(interference - acceptable)' - our son was here at the time, and both his iPhone and iPad connected as it had done previously with the old router.
I remembered that I took screenshots of the settings on the first 7800n I had, so think the last one will have been the same - that one was set at: 'Channel 1 (2.2412GHz)' It never faltered.
On this new 7800NXL, there is no option for channel 1, but there is an 'auto' setting - just wondering if I should leave it on 11 or try auto perhaps?