A way to test if external interference is causing your problems is the use of an AM (medium wave) radio.
Tune it to around 612Khz during a time when you are not having any problems. Keep it away from the computer/monitor/TV sets while you do this.
Ideally, when tuned in , you will hear more or less nothing except a bit of hiss / the odd click.
Switch the radio on in the evening BEFORE your ADSL problem begins, and listen. When the packet loss problems begin, does the sound from the radio change?
(keep the radio a reasonable distance from the computer - you WILL hear noise if its too near, regardless).
I get occasional problems from external interference, it manifests once a week or so for a few hours, and appears as a loud buzzing noise around 612Khz on my radio. At other times this frequency is silent (or occasional very distant foreign stations at night).
If you DO detect interference on the radio, you can then use it to walk around your house / nearby area and see if it is louder at any particular place, which might indicate it's source.
I found a failing PC power supply causing me problems, and a few months later, a cheap external power supply for a USB hard disk also causing interference and knocking my ADSL out. Switching these off silenced the interference on the radio and after a reboot, my ADSL packet loss disappeared.
Ian
