X10 Testing

["Mark Hindess" <ukha@xxxxxxxxxxxxxxxxx>]

I bought/borrowed an X10 testing set from letsautomate.com to try to
get to the bottom of some problems in one area of my house.  I turned
off all the circuits in the house except the CM11 circuit and the
problematic kitchen circuit.  I got no reading on the test receiver.  I
turned off all the appliances one-by-one.  I still got no signal.  As
I was giving up I started switching things back on.  I turned *on* a
switch for a fused spur that connects a dishwasher and to my great
surprised suddenly I got 200mV on the receiver.

I'm assuming that there might be a wiring problem in this fused spur.
Is there any other explanation?

I then began turning on other appliances.  I turned on the fridge -
which is connected through an X10 filter - and the signal dropped to
100mV.  I turned on the microwave - also connected through an X10 filter
and the signal dropped to 50mV.  Finally I turned on a PC and it dropped
to 25mV.  I put a filter on the PC socket but the signal still dropped
to 25mV.  I thought filters were supposed to help - and perhaps they
are a little - but despite trying several different filters I still
see a significant drop in the signal for filtered appliances.

Is this normal?  Any suggestions welcome.

Regards,
Mark.

P.S. Happily the kettle is now working reliably with the limited signal
but I'd still like to understand what is going on.