Active USB extension cable not working. Ideas?

[Triggaaar]

I've bought a few USB 2.0 Active Extension cables (see here, because my PC is going to live under the stairs, and I want to use USB devices in my study. Before putting all the calbe in place, I thought I'd test it, and it's useless.

It says you can extend up to 25m (serially connecting up to 5 segments) with no signal degradation.

Well trying one works fine (USB FF steering wheel detected). Using 2 does not work (the wheel jerks, showing it has received some sort of signal). Strangely, using 1 5 metre cable, plus a cheap 3m non active cable, plus a 1m 4 port USB hub (not active) does work. ie 9m, with 4 metre not active works, 10m, all active, does not work. This suggests to me that the active repeater simply isn't doing anything.

Anyone had any experience with these, or got any suggestions?

Many thanks

[Triggaaar]

More testing done, and this is now very stupid:

PC -> 5m active cable -> 3m cheapo cable -> 3m cheapo cable -> 2m cheapo cable -> 1m cheapo hub cable -> Steering wheel - works (that's 14m, mostly non active)
PC -> 5m active cable -> 5m active cable -> Steering wheel - Doesn't work!

Both 5m cables work in the first example, so it's not like I've just got a broken cable.

Unfortunately, it's very important I get this to work, or sticking the PC under the stairs and running cable to every room in the house, will have been a bit of a waste of time.

[Triggaaar]

In case the Hub was boosting the signal (unlikely given the cost, and that it's 1.1, not 2.0) I tried adding it to the 2* 5m cable example. This still does not work.
Windows recognises the hub (new generic hub detected) and cannot recognise the device attached to it (an error message appears).

[Triggaaar]

Ahhhhhhhhhhhhhh!!!! I hate computers.

Ok, remember the
PC -> 5m active cable -> 5m active cable -> Steering wheel
scenario - doesn't work.
PC -> 5m active cable -> 5m active cable -> 1m cheapo hub cable -> Steering wheel - also didn't work.

Get this:
Add a 3m cheapo cable, in between the 2 5m active cables, and it works! ie:
PC -> 5m active cable -> 3m cheapo cable -> 5m active cable -> 1m cheapo hub cable -> Steering wheel - Works!
Take the cheapo calbe out of the middle, and it comes up with 'USB Device not recognised' again.

The 3m & 5m cables are all supposed to be USB 2.0 compliant. The USB hub is supposed to be 1.1.

If I could be 100% sure that 5m -> 3m -> 5m would always work, I'd put them under the floor, but I'd like to know what's causing these peculiarities, so I know I won't have to take the new carpet up.

Any ideas?

[Triggaaar]

It seems that if I connect 2 of these 5m active cables together, it stops working, but if I put something in between them, it's ok.

PC -> 5m active -> 3m -> 5m active -> 3m -> 5m active -> 2m -> 1m hub -> Steering wheel - works