BT Home Hub 5 and Devolo 650+ powerline - conflict?

Can anyone think of a reason why using homeplugs would cause the BT Infinity HH5 to disconnect from the internet when attempting to download anything beyond a basic webpage in size?

Since last Thursday I have the BT Home Hub 5 connected to a Devolo 650+ unit with another one upstairs (1st floor) connected to the PC. I have an internet connection but if I try watching a video on Youtube, run a speed test or download anything, the hub disconnects.The Devolo units have a good connection with each other (the software says 450-500mbps on average) and the Hub works for wifi and with a laptop plugged directly into it.

I can't find an explanation for this. It isn't the LAN cables or the sockets (tested that) or being upstairs (same result occurs downstairs in the same room as the hub and other homeplug). I'm not sure whether to think the homeplugs are faulty or the BT hub is faulty (despite it behaving normally otherwise). I'd be grateful if anyone has any ideas, thoughts or solutions to share.

*Drat...I missed an 'l' out of my name when registering. This day just gets better all the time*

Do WiFi speeds remain good even when the homeplugs are playing up?

Not entirely sure on that. I'm trying a sort of test now by running the speed test thing from speedtest.net whilst running youtube on the ipad via wifi. Weirdly, it has completed the test multiple times in a row without failing for the first time and has given the highest speed rating of (a rather meagre) 15mbps, when before it is 1-2mbps and then fails.
Hmmm I just ran the test again having stopped the youtube video on the ipad and it completed with a speed above 30mbps. Weird. I have no idea what is going on.

Are the homplugs in the same socket as the HH5? They shouldn't be on a mains extension lead either.

Was trying to see if the HH5 and Homeplugs were interfering with each other, since they use the same frequencies

speedtest.net is not ideal for this sort of thing since the results are skewed to showing the maximum. Try ours http://wwww.thinkbroadband.com/speedtest.html which can show the graphs after too

No. Originally I had the HH5 plugged through the homeplug (they're passthroughs), but then moved it to the other side of the room. The one upstairs is on it's own socket with nothing else near it. The Devolo cockpit software showed the transmission rate between the homeplugs go up by nearly 100mbps as a result.

Just restarted the PC upstairs and now it completes the speed test with 50+mbps without dropping out. Twenty minutes ago it'd fail after recording 1mbps.

Maybe the HH5 has 'settled in' now? I thought it already had as the wifi signal was fine and the laptop plugged into the HH5 directly seemed stable doing the same test. I'd assumed this was the plugs causing a problem but perhaps it was the hub or line in the first week getting itself sorted. Now I'm thinking I have been wasting everyone's time...er sorry.

The HH5 has been unstable of late, but perhaps BT have released new firmware which your HH5 has just updated itself with.

Ah right, I see. The TBB test gives 52.19 Mbps, which I guess is what I could expect when the BT prediction was for a max of 60 in this location.

I might have been more patient if the engineer had warned me it would take some time for the line to settle, but he was a contractor who didn't say anything.

Thanks for the information and apologies for what appears to have been rather a waste of your time in replying. Perhaps I should apply to have my forum name change to 'Silly_Sausage' or 'Impatient_Pillock'.

Worry not, you haven't wasted anyone's time. Welcome to the forum

I don't think it has updated today, the 'Helpdesk' page in the settings says it did that on 02/05/2014. I guess time will tell whether this is the line and hub working properly or a false dawn preceding further angst and disconnections.