Where electricity is fed via overground wires, the telephone lines are usually overhead too. Removing noise from electric cables is relatively easy, because the mains is 50Hz, and you just filter everything above 50Hz (ish). The problem with ADSL on phone lines is that the interference and the wanted signals both look very similar, so it's impossible to filter out the unwanted from the wanted.

Home plug will not work between adjacent houses because they are almost certainly on a different phase and thus do not have a common live connection. Every third house may receive teh signal but it is likely to be attenuated by distance.

As every socket in the house returns to a common point between consumer unit and meter, the filtering effect you mention would affect connections within the house as it will be presenting a low impedance path for the higher frequencies very close to teh common point and would thus attenuate the signals.

Not true. The attenuation of the HF signals would be due to the effect of the meter acting as a choke in series with the live feed. You may recall that a system which relied on ADSL delivery via mains wiring had to have a box installed in each house, because the ADSL signals would not reliably pass through the electricity meter.

P.S. The practice of wiring "every third house" is not carried out too much these days, because it is dangerous (nearly 500V between lives in adjacent premises is not a good idea when satellite dishes can be 2 feet apart). It is only done to even the load, and this is now achieved by wiring blocks of premises, and rarely done to single dwellings any more.

Edited by deleted (Fri 09-Mar-07 09:54:10)

I was having similar problems with my snr dropping to minus figures every eve between 5.30 and about 8, Idnet my isp did all kinds of test's etc .
I decided to change my internal wiring I fitted an adsl nation pre filtered faceplate and a adsl 2+ rj11 lead . The snr has not dropped since and am synced at 8128 so that seemed to cure my problems may be worth a try cost me