Discussion in 'EMC Matters' started by Colin G6MXL, Oct 26, 2018.
I have received a report from a new neighbour that I am causing his lights to come on and off when I transmit. He is also reporting some TVI (which I happy to investigate and try to resolve). I have little doubt that it is my transmissions that triggering this (it coincided exactly with my first time since they moved in about a month ago).
I was running about 70W to a trapped dipole on 30m (10MHz) at about 6 to 8m above ground and about 4m from the nearest point of his house. I believe that my transmission was reasonably clean (70 Watts out from a 100 Watts transceiver, no processing and no ALC kicking in). I wonder if anyone has had any similar experiences with the touch sensitive lighting and how they went about resolving.
Relationship with the neighbour is good and I intend to keep it that way. I have arranged to visit in a couple of days to get some factual information regarding the touch sensitive lighting. No problems reported by previous neighbour over 15 years.
Hi Colin, touch lights are always a problem due to very poor design, there is no way to fix them due to this other than to hard wire them, i am assuming of course that they are table type lamps fro your brief description.
As for the TVI then i think you need to look into there TV set up regarding there antenna and how many points there are for other TV`s in the house with what type if distribution system they are using.
The days of us causing the problem are long gone so it will i am sure be down to poor antenna installation.
We at the EMCC are always interested in odd problems Colin, is there any chance that you can give us the details of the light switches that are having this problem.
Are they the table lamp variety or wall mounted types, look forward to the details.
A reply Colin would be appreciated as we need to log problems like yours for future reference.
Hi Ken. They are a bed-side table lamp variety. They have a CE mark on the box, and are supplied by John Lewis. I'll add the specific model number when I find the paper where I noted it. They appear to be double insulated (two square box). I need to work out the best way to explain the situation to the neighbours.
OK Colin, sad to say that although they have a CE Mark then that does not mean they are compliant.
In fact they do not and never have conformed to EU standards.
Even John Lewis would not have known that so the only way and I have done it myself is to hard wire them.
I am talking to Dr David Lauded G0SNO who writes the EMC Column in RadCom who is interested in your case.
Look forward to an update as and when.
Hi Colin, sorry to be a nuisance but i have been looking on JL`s web site and i see to my amazement that they still sell touch sensitive table lamps.
When you have time and i appreciate that that is not easy under your circumstances then i will look forward to know the exact model of lamp in question.
Hi Ken, my neighbours have 6 or 7 of JL's model number 706 70108 - they were on sale a week or so ago when I checked in the local branch. In addition they have 1 of an older model brought from their previous house JL's model 706 03124 which I suspect is discontinued. There is mention on Page 79 of the February 2005 RadCom and on the ARRL's QST from 1995 (see link https://www.arrl.org/files/file/Technology/tis/info/pdf/49572.pdf).
Yes Colin we know about that ARRL link.
We do know that they were approved in the US but not in the UK.
Thanks for the details which now I can give to JL when they get back to me and also pass on to David Lauder.
As well as the In Practice article by Ian GM3SEK you refer to, John G3NCN when he was a volunteer on the EMC committee did quite a lot of investigation on one of these touch sensitive horrors that one of his neighbours had. He found that most of them are made somewhere in VK land. I remember John failed to cure his even though he tried everything. You can contact John by via the details on QRZ.COM, not sure if he still has the details.
Dave, all the ones that JL are selling at the moment are made in China, what a surprise.
Thanks Dave G3YMC. I've just dropped an email to John G3NCN.
I think although it is a good idea to get a different opinion than my one, then John i feel that he can only tell you what he done back then some 18+ years ago only that as Dave has said He failed even though he tried every thing.
Maybe these are of a different design but still crude, so i will get back to you once JL have replied to my email.
Thanks Ken. I certainly didn't want to cause offence. I hadn't realised the timescales.
No offence taken at all Colin, yes things were a bit different back then and i also had a couple of those lamps to and was amazed at how poorly constructed they were.
David Lauder said that they used a chip that drives the metal body of the lamp with a square wave at somewhere around 150 - 200 kHz.
They could only meet US FCC specs that don't have limits below 500 kHz but they failed European specs for conducted emissions from dimmer switches and controls. These standards were compulsory even before the days of the European EMC Directive.
As soon as JL get back to me then i will be back in contact.
Colin i have just heard back from Daviv Lauder who asked some questions, which are What frequencies cause the touch lights to go on and off, at what power, what distance and what type of antenna?
He has also mentioned about standards, this is what he has had to say.
Regarding CE marking, the first thing to find out is who imported it into the EU and CE marked it? Recent products normally have the name and post code of the importer on the label. What we need to see is a copy of the EC Declaration of Conformity hat lists what standards it complies with for EMC Directive and Low Voltage Directive. The importers are not obliged to provide this to anyone other than the competent authorities but some include it in the instruction manual or make it available on request.
For immunity of lighting equipment, there is a standard EN 61547:2009, Equipment for general lighting purposes. EMC immunity requirements which cross-references various EN61000 series standards.
For emissions, it should comply with EN 55015:2013+A1:2015 but not all touch lights do as they normally drive a frequency around 200 kHz onto the body of the lamp. It would be worth asking Colin to tune across the LW broadcast band with AM detection and listen for any buzzing that peaks at a certain frequency. Of course there are lots of things like switching power supplies that can cause this. If we can get one to test and if it fails EN 55015 then we could point that out.
Some of this i will ask JL to answer.
I will buy one of the touch lights from JL so that I can be certain of getting everything that is supplied as normal. I'll also arrange to conduct some controlled tests with the neighbours on a number of bands (most likely 30m, 17m and 12m) and power levels (between 5 Watts and 100 Watts) into my trapped dipole antenna. I'll get back to you when I have done the tests (most likely after the weekend).
OK Colin look forward to the results.
Colin, JL have returned my email and will pass my details on to there specialist people and will contact e next week.
I've bought one of these lights from JL today, brand new in a still sealed box. I have tried it next to a domestic long wave AM radio and with mains supplied it is producing strong signals on the long wave band with strong harmonics throughout the medium wave band (AM) and somewhat weaker harmonics into the lower broadcast shortwave bands (AM). When you touch the base of the unit you can hear a very slight change to the signal. I don't think you could realistically use one of these next to a domestic LW/MW AM receiver.
There was absolutely zero documentation supplied (not even assembly instructions to fit the bulb and the glass shade). There was some very minimal information on the box and on the base of the unit. The mains plug has a plastic earth pin. I'll send photos shortly.