Eugene's observations

Occasionally an internet connection drops periodically,  this is normal and usually not noticed.  But sometimes it drops frequently or regularly (or both).  When this happens we can often diagnose it as being external factors that the internet service provider (ISP) will get sorted out for you.

Sometimes though the ISP reports that there is no loss of connection from their end.  Now we have to look closer to home and by connecting to the master socket, thereby disconnecting the internal wiring asnd other appliances, it is often possible to confirm the location of the fault.

But if there is no fault seen after the above checks, and (usually) the problem is with wireless but not wired connections, then the possibility of Repetitive Electrical Impulse Noise (REIN) or Single High level Impulse Noise Event (SHINE) must be investigated.  

There are very thorough descriptions of these events elsewhere (see rererences below) so here I shall limit myself to saying that interference can be caused by electrical items emitting a disruptive signal that can cause poor broadband performance.  Not only dropped connections, it may be the ISP will automatically lower the speed as it prioritises stability over performance so the issue can manifest in different ways.

The solution is to make sure that your router is connected to the master socket and at least a metre away from all other electrical devices.  This applies to the wires close by the router too as they can act as antenae that broadcast the interferance.

The test for this is to get a mediium wave band radio and tune it in to the frequency that causes the disruption: 612 KHz.  Move the radio arond the router and you should hear the white noise much louder when close by the router and fade to nothing as you move a few inches away.  

Examples of causes of REIN include:

• Faulty power adapters.
• Timed devices, such as central heating.
• Christmas tree lights (especially on ?flash? setting).
• lighting.
• Roadworks.
• Faulty set-top boxes, televisions and other appliances.
• Power cables running close to telephone wiring in the home.

More info from: http://www.kitz.co.uk/adsl/rein.htm