wireless constantly dropping in and out

[#1]

Can anyone suggest anything for me to try.
My PN router is constantly dropping in and out with the wireless.  On ethernet its fine just wireless is an issue.  I had this issue when I first signed up and PN sent me a new router but its happening again 
I have moved the router away from all other electrical items in the house.  I have updated the wireless driver on the laptops.  Thats 4 different models of laptops all using different wireless cards.
All 4 laptops drop out at exactly the same time so I would suggest thats its a router signal issue but I am after a sanity check from you guys and possibly the PN tech folks.

[#2]

Have you tried changing the Wireless Channel?

[#3]

Do you notice if the router reboots when the wireless goes off - check the uptime under broadband connection menu... This router has this problem in some circumstances and there is currently no fix for it.
There is a thread about this where others have been having reboots when using wireless but I can't find it at the moment.
If it's not rebooting try a different wireless channel.

[#4]

Thansk for the qucik response folks.
I have been using all  the channels systematically.  I have used different channels to the neighbours and also deliberately using the same as the neighbours to see if there was any difference but there wasnt.  Also the router hasnt been rebooting as I have been sitting connected to it using ethernet from yet another machine to confirm that it was staying up.
I was using a channel scanner to view the signal for the router as well and I can clearly see my router drop its signal when the neighbours routers remain stable.  Currently I can see 11 different routers locally and none of them drop signal strength so it seems to rule out interference.

[#5]

Well I think I have managed to crack this one.

I took it a little to the extreme and got 12 wireless routers and set them all on different channels.   Then I downloaded inSSiDer from this web site....
http://www.metageek.net/products/inssider
This shows a constant graph of signal strength etc.  I watched this constantly for over 3 hours ......it was mind numbing but very worth while.  Eventually I saw that at certain times and for very bried periods that a couple of channels were plummeting for all of the routers.
Unbelievably I have found that I am getting a better service using a channel that has other people on it as opposed to a totally free channel which is what most wireless experts recommend you use.  All I can assume is that someone or something nearby is causing interference that is so rapid that without this tool I would never have spotted it.
I would seriously recommend that you try this tool.  They do offer more complex tools that allow you to track down the sources of the interference buit this one is free and seems to get some good reviews around some of the techy/nerdy websites.