Re: R.F. from X-10 dimmers

[Nigel Orr <nigel.orr@xxxxxxx>]

At 23:34 08/03/99 +0000, you wrote:

>   Following installing the new U.K. X-10 wall dimmer switches  in
place

I should say that I don't use X-10, but I have a reasonable knowledge of
phones, dimmers and buzzes- someone else may have more specific
solutions...

>that the buzz on the phone line gets louder the dimmer the lights
are!!.

If the buzz is from the actual dimming circuit, it should be at its worst
when the lights are at 50%, and improve as the lights turn fully off or on.
It should also go away almost completely if you remove the bulbs.

>I have complete segregation between my mains wiring and my phone line,
>so it's not induced A.C.

It is possible that your phone line is tied to local mains ground at some
point (it shouldn't be, at least not at your house end)- this can be tested
by the phone company (and I think there's an option on the 17070 test
number which checks it, but you may be safer avoiding that...).  If this is
the case, you, or the phone company, need to find and repair the fault (if
it happens particularly in wet weather etc, it could be in a trench
somewhere, rather than round your house...)

> The dimmer switches are emitting strong radio
>interference with a range of 8-10 metres. If I switch off all the
lights
>the buzz on the phone line stops completely and my powermid receives
all
>signals 1st time. After checking the X-10 din rail dimmers, I've found
>they also have this problem.

If you can confirm that the noise is not from the actual dimming circuit
(ie doesn't peak at 50% brightness), and that you don't have a low energy
bulb or fluorescent on one of the dimmers, it's probably some other RF- you
could carry a portable radio round the house and see where it picks up the
strongest noise to try to find the culprit.

Hope that gets you started...

Nigel
--
Nigel Orr                  Research Associate   O   ______
Underwater Acoustics Group,              o / o    \_/(
Dept of Electrical and Electronic Engineering     (_   <   _ (
University of Newcastle Upon Tyne             \______/ \(

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