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Finding YOUR OWN QRM


#1

Ever thought of checking what devices around your home might be making some of that S8 noise level you get on HF while trying to chase that distant, weak SOTA activator?

Normally e-smog detecters cost in the range of 120-160 EUROS or more. They do have lots of useful features however the simple one I have found at 14 Euros including free shipping, sounds just like what every radio amateur should have. Useful to use around his or her house and find what computerised equipment, PSU, kettle, refrigerator, TV etc. is generating RF interference.

I’ve ordered one and I’ll be creating a report for the ICQPodcast, hopefully in the next couple of weeks. The earliest it was predicted to arrive here was today however I suspect it’s more likely to arrive early April. That being said 15 minutes after I ordered it last Sunday, it was confirmed as being shipped, so maybe I’ll see it sooner rather than later.

Here is the description and specs:
Electromagnetic-Radiation-Detector-Digital-LCD-EMF-Meter-Dosimeter-Tester
SKU: 14_AM000114005171

Easy to use electromagnetic radiation detector provides a quick, reliable and convenient way to measure electromagnetic field radiation levels around power lines, home appliance and industrial devices. This electromagnetic radiation detector can be widely used for office, indoor, cell phones, computers, air conditioner, refrigerator and more.

Description:

Simple operation, fast measurement of electromagnetic radiation for electric appliance, wires and more
Wide Frequency Range: 50Hz-2000MHz
LCD display with max. reading up to 1999
Sampling Time: Approx. 0.4 second
Working Voltage: 9V
Size (L x W x T): Approx. 5.2 x 2.7 x 1.2 inch
Housing Material: Plastic
Color: Black

Way To Detect:

Press the power switch to turn it on, hold the detector near the device to be tested
The more close to the device and the higher readings it will get, remote testing for high voltage objects
Try to change the measuring angle during testing, to achieve optimum detecting effect

or from eBay UK (there are several, so search on EMF meter to get the absolute cheapest).
http://www.ebay.co.uk/itm/Electromagnetic-Radiation-Detector-Digital-LCD-EMF-Meter-Dosimeter-Tester-/201232490867?pt=LH_DefaultDomain_3&hash=item2eda642173


#3

I’ll be looking forward to reading about your findings with big interest.
Everybody know that the antenna type, polarisation, height, etc has a big influence in the amount of domestic QRM they catch.
When I moved to my current QTH and before having my current tribander yagi installed, I suffered huge amounts of domestic QRM due to having an inverted L shape random Long Wire antenna. This long wire antenna caught noise from everywhere, refrigerator, mobile phone chargers, laptop, laptop charger, hairdrier, everything.
Now, since I got the yagi installed, noise has decreased a lot with respect to the inv L LW, however there is still two things causing bad QRM. These are a couple of LED light bulbs that I bought some time ago and have in an upstairs bathroom. These are the only LED light bulbs I have in the whole house and I’m seriously worried because I heard that the EU regulators have forbitten or will forbid the use of low consumption lamps because of their Mercury vapour content, highly toxic and very difficult to recycle.
I wonder whether the problem I have with these only 2 LED bulbs I have is due to they being faulty ones or this is a problem with all LED bulbs.
I suppose many of you have these type of LED bulbs. Do you have any QRM problems with them or caused by them?
Cheers, Guru


#4

That looks like the sort of thing bought by people who believe that EMF and Electromagnetic Radiation makes them sick.


#5

Untuned e-m field detector 50Hz to 2000MHz. I’m not convinced that it will help in detecting HF QRM. Let us know when your review comes out.


#6

At least around the house you can switch things off and see wot happens.
Never really thought the PC or the screen would cause QRM levels will have to turn them off one day see if difference is there or not.

Karl


#7

I have found a AM transistor radio or portable shortwave radio useful for tracking down r.f interference.

Don’t have any LED lightbulbs as have read they can produce r.f interference.

The fluro type bulbs are shocking sources of interference.

Generally stick to the quartz halogen bulbs with a few old incandescents here and there in low usage applications.

Cheers, Nick


#8

My report is in the latest ICQPOdcast - in short DON’T BUY the EMR detector - it’s a waste of money!
The case might be useful to build something else into but the device itself is worthless for the application I wanted to use it for.

Ed.


#9

Yes Nick. About a year or so ago a ‘new’ noise appeared here. My main radio is a Flexradio but by good fortune I also have a 897D.

Having turned off the power supply to the house, with the 897D on battery, the noise continued so not the house. I then did a local walkabout. A neighbour had bought a Chinese ‘electronic organ’ , the notes were not too bad but the PSU for it was :wink:

Mike


#10

And did he do anything about it, Mike? If he is anything like the neighbours around here, he wouldn’t want to know, and he would treat you as if you were some kind of a crank.

My latest problem is constant S9 QRM on 15, 17 and 20 metres from newly installed solar panels next door. I am getting nowhere in my efforts to get it fixed and the neighbour will not give me access to his premises. The noise is coming from the inverter which converts the DC from the solar panels to AC. I am fairly sure that a couple of clip-on ferrite chokes on the DC wires leading into the inverter would cure it, but I cannot get any co-operation either from the neighbour nor from the company who installed the equipment.
:frowning:

I am going to try Ofcom next, but I’m not optimistic.

73,
Walt (G3NYY)


#11

Hello Walt,
Well Richard the neighbour was very helpful and let me poke about the inside of the organ but he did not want the organ “fiddled with” as it may void his warranty so I went no further. On the good side his wife got bored with the thing and I suspect it has just become clutter in their living room as I have not heard that source of QRN for four months now.

As regards the solar panel inverter problem you have there has been mention here about such things in the past I recall and also a lot of traffic on the web about inverter noise. If the panels are newly installed do you know who did the installation? Might be worthwhile having a chat with them if only to identify the inverter make code…

Good luck & night night.
Mike


#12

Please … :anguished:


#13

Well I’ve just spent 45mins not finding the source of the QRM but finding any kind of mobile signal! However, a lifetime of tinkering with wireless means if there is a signal I will find it. My phone is currently taped to a long garden pole and that is poked up through the shrubbery here. We went from emergency only service to 14mbps 4g… a result in anyone’s books as the mobile provider and government signal finder websites suggest making any calls around here is very unlikely. Phone is set to mobile wifi hotspot and I’m sat on the patio with some viable internet and a bottle of Glen Livet. :wink:

I do think that Mike is trying to win a “Finbarr Saunders” award with his anecdotes. :wink:


#14

Hi Mike,
Walt said he could not get any cooperation from the company who installed the panels. That would have been my suggestion as well - technician to technician often works best. Walt said he is now trying to involve Ofcom. Of course if the Invertor was reported as apparently causing interference to mobile phone calls/Internet access or local TV, he might have a better chance of getting some assaistance I suspect.

Ed.


#15

For broadcast services Ofcom offloaded the complaints procedure to the BBC - and if you don’t have an external antenna with line of sight to the transmitter and at least 1 volt of RF on the terminals they are not interested!!

My experience with Ofcom is the exact opposite - two problems affecting my amateur radio reception, both solved within a week (BT Vision, LED bulbs).

Incidentally, our shop and flat are fitted throughout with LED bulbs or fluorescents with almost imperceptable increase in the noise floor - not the expensive type of LEDs but of Chinese origination but there are good and bad ones (if anybody in the UK wants to know my supplier email me). I have a bad one (from the Ofcom investigation) which produces almost perfect white noise certainly from MW broadcast to 23cm - just need to calibrate it!!! :wink:


#16

@G3NYY I know someone else that got Ofcom involved with QRM from a local SV array (not a great distance from Tewkesbury) and the last I heard was that Ofcom agreed that is was coming from the said premises but claim they have no powers to do anything about it.


#17

Yes, Stewart, I have heard similar stories.

The last time I got Ofcom involved it was relating to a cheap Turkish-made TV set which produced S9 hash 24/7, regardless of whether the set was being watched or on standby. Of com did attend, but said there was nothing they could do about it because it was not interfering with local broadcast reception and therefore it was “within spec” as far as they were concerned. The neighbour and his wife have been “not speaking to me” ever since, and have done everything in their power to turn the other neighbours in the road against me. Four or five years later, the set blew up and the problem was solved.

73,
Walt (G3NYY)


#18

Hi Barry,
That’s good to know that Ofcom can be responsive. I have often heard good things of them - I suspect the fact that several of the inspectors are radio amateurs doesn’t do us any harm HI. But as others have added, finding the interference is the frst step, if Ofcom are powerless to do anything, where do we go?

I’m surprised that Ofcom outsourced TV intererence to the BBC, hardly an independant body, but I suppose you could see it that the BBC would work harder to stop people interfering with their signals.

OK on the LED bulbs as well - as you say not all are bad and in fact it’s not neccessarily the cheapest ones that are bad!

It would be nice to know a supplier of good LED bulbs over here, but for the time being, I simply avoid them like the plague!

73 Ed.


#19

The County Council have announced that ALL the street lights in Gloucestershire are to be replaced with LED bulbs.

73,
Walt (G3NYY)


#20

All the street lights in my street were replaced with LEDs a couple of years ago, I have had no problems with them. The first thing I did was put a multi-band whip on the 817 and walk around the nearest few lamp posts. Nothing, clean as a whistle. Perhaps I’m just lucky!

Light pollution is another matter - there is enough light to read a newspaper even at the midpoint between two lamps, but at least they are designed to cause minimum sky light so in my back garden I can still see the stars if no fox or cat has set off the neighbours security lights!

Brian


#21

With LED lights, PV arrays etc - Its the power conversion beneath them that generate all the rubbish that we sometimes have to endure through careless design.

There is an interesting article in RadCom this month looking at the possibility of a rising floor due to some of this noise being propagated by the ionosphere. If only world leaders had the same attitude to this as they do with global warming worst of all its completely avoidable, the amount of testing UK produced equipment has to go through before its approved, it really should apply to imported electrical goods as well.

Live in the middle of nowhere - away from it all is the best solution.

Jonathan