Message-ID: <000601c0901a$b729e720$e46c74d5@w8k3f0>
From: "Dick Rollema" <d.w.rollema@freeler.nl>
To: rsgb_lf_group@blacksheep.org
References: <004401c08fc3$0583eae0$044f073e@default>
Subject: LF: Re: Fluorescent light QRM
Date: Tue, 6 Feb 2001 09:52:33 +0100
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To All from PA0SE

Alan Melia wrote:

> Our switching should be in the 'live' side in the UK, I wonder
> if Dick has a tube switched in the neutral line.

The straight fluorescent tube above the the kitchen sink has its own switch
fitted to its "holder" ( for want of the correct word I don't know). At one
end of the holder is a three-pin connector for a mains cord that disappears
into the kitchen furniture and leads to a plug in a socket hidden somewhere
behind a panel. The Dutch plugs don't have the British third pin and the
plug can be inserted in two ways, 180 degrees apart. I found that the plug
was inserted such that the switch on the tube holder was in the neutral
wire. I did not feel like removing the panel to get access to the plug so I
interchanged live and neutral wire in the connector on the holder. Now the
switch is in the live wire and the noise is gone when the tube is switched
off; the normnal situation during daytime when I operate.
How the tube could generate noise when connected to the live wire only
remains unexplained. Perhaps over the years an insulation fault  has
developed inside the tube, causing the noise, and the noise current flew via
the capacitance and/or leakage path of the open switch in the neutral wire.
The noise source must be in the tube itself because it disappears when the
tube is removed from its holder.

I have two fluorescent tubes in the shack and they generate no noise at all!

73, Dick, PA0SE