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EMF Testers - Why Are They Different? Mel8704 vs DT1130
#1
I've used DT-1130 as my EMF side-arm for a while now, mainly because I'm brutal at dismissing evidence, and the DT-1130 is generally unequivocal, never giving me annoying false positives... and also because it's pretty cheap. I use it alongside other equipment mainly, rarely does it go solo, because of the nature of EMF signals, a detection on the meter isn't a really complete piece of evidence.

Recently I've started bring a Mel Meter to the party, and I find myself a little perplexed by the results it brings back. For a start it seems more sensitive. But more than that, it seems to pick up a lot that the DT-1130 doesn't. But the DT-1130 seems to pick up a lot that the Mel Meter isn't particularly interested in. I suppose I can use them together as necessary, but I'd like to have a full understanding of the differences. Hopefully someone can explain this to me in a way I can grasp.

My guess is that it's to do with the frequency of the EMF, I think the Mel-8704 goes down to 30MHz? This steps outside my understanding for now, and is what I'd like to discuss. A basic how-it-looks is that the DT-1130 doesn't read anything straight out the door of a microwave oven but it drives the Mel-8704 insane. Yet if I shove their faces into a domestic power outlet, the DT-1130 is the one that sounds the alarm, while the Mel-8704 barely registers anything above baseline.

[Image: index.php?app=core&module=attach&section...h_id=13124]
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#2
get a triaxel for accuracy.
Now most people are doing emf wrong. I will suggest this for your reading pleasure.
http://www.assap.ac.uk/newsite/articles/...lines.html
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#3
(11-18-2016, 07:39 PM)Faranormal Wrote: Recently I've started bring a Mel Meter to the party, and I find myself a little perplexed by the results it brings back. For a start it seems more sensitive. But more than that, it seems to pick up a lot that the DT-1130 doesn't. But the DT-1130 seems to pick up a lot that the Mel Meter isn't particularly interested in. I suppose I can use them together as necessary, but I'd like to have a full understanding of the differences. Hopefully someone can explain this to me in a way I can grasp.

My guess is that it's to do with the frequency of the EMF, I think the Mel-8704 goes down to 30MHz? This steps outside my understanding for now, and is what I'd like to discuss. A basic how-it-looks is that the DT-1130 doesn't read anything straight out the door of a microwave oven but it drives the Mel-8704 insane. Yet if I shove their faces into a domestic power outlet, the DT-1130 is the one that sounds the alarm, while the Mel-8704 barely registers anything above baseline.

These EMF meters are designed for engineers, not ghost hunters & the ones that claim to be are often very poorly designed circuits with poorly designed boards that do not shield one part of the board from another, thus causing their own false positives.
The meters own manual should tell you where the internally generated frequencies are. They are called sprogs & there will many of them between the Hz & Gigahertz on these things, even on a well design circuit.
There are 1000 Hz in a kilohertz (Khz) & 1000 Khz in a Megahertz (Mhz) & 1000 Mhz in a Gigahertz. And given that anything has a band width, that is it does not exist on a single frequency only. It has an area of coverage with a centre point. So a few Hz is nothing either way. Even a bat call which has a very narrow range covers more than a few Hz. Some species cover several Khz. The frequency in Khz, tells you the species.
These meters should both go down to at least 30Hz & they should both go up into the GHz range. So they will pick up anything & everything from lightning strikes to bat calls, to broadcast transmitters to car key fobs, to Taxi's, to TV remotes, to Microwave Ovens, to CB's to passing Aircraft, to anything else from mobile phones to baby monitors & electric fences & peoples solar panels, street lights, car electrical systems & pumps in fish tanks/garden ponds etc etc etc etc. Even welding produces an RF electromagnetic field. And that is just the things that produce Radio Frequency & there are two other types of EMF, so unless you know what these things are actually hearing how do know what anything is?
Also how do you find the baseline readings?
I know for a fact that there are some frequencies that I only hear active at certain times of day & for very short periods. Some are more active at weekends or during the evenings. Others go quiet at the weekend & during the evening & then you have the passing sources. A motorcycle riding instructor. A beep from a cars remote control or passing helicopter with not only it's radios, but also it's helmet to helmet comms, which are on a known frequency too. You could even pick up a satellite or the ISS & not know it & with a space source due to doppler effect they change frequency by several KHz between approach & departure.
My radio scanner has over 600 channels programmed in that I monitor regularly & I only listen between around 100 MHz & 500 Mhz on that radio. On my scanner I do not have broadcast, amateur radio, taxi's & a whole load of other things as they bore me. But I do have several other radios that allow me to cover the massive amount of spectrum between Hz & Gigahertz & I do have things I like to monitor on various parts of the spectrum.
Edited to add.. My scanner has over 600 known sources of EMF, in a very narrow frequency field compared to your meter, worth listening to local to my home & my handheld scanners then allow me to monitor interesting EMF sources away from home. How many potentia sources do you think your meters potentially have at any location?

We all believe in something greater than ourselves. Even if it's just the blind forces of chance. Ambassador G'Kar.
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#4
Good information, Janus. It helps to remember what an EMF detector was designed and intended to do. Some of them, like the simple K-II meter, were designed to spot potentially hazardous EMF produced by electronic equipment from equipment such as microwaves, broadcast equipment, and other powerful electrical gear. Some of the more sensitive detectors are for finding sources of electrical interference in testing labs on electronic equipment such as computers or sensitive sound equipment.

Since electrical equipment can be switched on or off and the test only picks up the presence or absence of an EMF field they may not be made with any direction in mind. Some will only sense in one direction or several directions but in one "plane." This leads to people getting false reading by moving the equipment around such as being handheld. The detector might not pick up EMF interference when held at one angle but suddenly pick up EMF when held in the same place at another angle. If a researcher doesn't understand this they might think that a phenomenon is suddenly appearing and disappearing.

Equipment also typically senses a given range or switches between ranges but rarely go below 30 to 40 HZ. It has been pointed out by some researchers that most naturally occurring EMF is either below 40 HZ or extremely high in the GHZ range. If paranormal events happen in a very low frequency range then an EMF meter would not register them at all. I've wondered if any researches have considered "capturing" EMF signals to be analyzed later. As most electrical equipment produces signals at multiples of AC frequency the source of EMF can often be identified as manmade or not. In the USA most EMF would be multiple of 60 HZ. In Europe and other countries EMF would be multiples of 50 HZ. This is not always true as broadcast frequencies are a selected range, but EMF from power supplies, lighting, and electric motors would almost always follow this rule.
-DFB

Subject: I have a black cat.
Believer: Black cats are bad luck.
Non-believer: It's just a cat.
Crackpot: Black cats are part of the New World Order government conspiracy.
Skeptic: I can test if black cats are more or less lucky than another cat.
Cynic: You only have a black cat to gain power and prestige.

https://www.youtube.com/watch?v=t9iIf4tFoyE

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#5
(11-19-2016, 11:00 AM)Darkforeboding Wrote: In Europe and other countries EMF would be multiples of 50 HZ. This is not always true as broadcast frequencies are a selected range, but EMF from power supplies, lighting, and electric motors would almost always follow this rule.

Multiples of a frequency are called harmonics & in general they get weaker like ripples on a pond, as they get further from the fundamental frequency. What happens with electrical items is not that they produce harmonics of 50hz. But that they produce radiated Radio Frequency (RF) due to their own circuitry. It's called RFI, Radio frequency Interference & it is a big problem.
This can be a massive issue that causes interference to a variety of people. Reasonably recently for example, a schoolboy had a TV antenna amplifier that jammed passing aircraft due to a fault in the amplifier.
And a lot of people find DAB listening can be hit & miss due to interference jamming their radio.
So called PLT. Power Line technology. Can be a nightmare, as it introduces deliberate wideband interference into your own homes electrical system & despite what manufacturers claim this does often travel beyond your own home. And it is one of the most biggest causes of RF pollution in residential areas.


http://www.ukqrm.org.uk/

We all believe in something greater than ourselves. Even if it's just the blind forces of chance. Ambassador G'Kar.
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#6
(11-19-2016, 12:00 PM)Janus Wrote: Multiples of a frequency are called harmonics & in general they get weaker like ripples on a pond, as they get further from the fundamental frequency. What happens with electrical items is not that they produce harmonics of 50hz. But that they produce radiated Radio Frequency (RF) due to their own circuitry. It's called RFI, Radio frequency Interference & it is a big problem.
This can be a massive issue that causes interference to a variety of people. Reasonably recently for example, a schoolboy had a TV antenna amplifier that jammed passing aircraft due to a fault in the amplifier.
And a lot of people find DAB listening can be hit & miss due to interference jamming their radio.
So called PLT. Power Line technology. Can be a nightmare, as it introduces deliberate wideband interference into your own homes electrical system & despite what manufacturers claim this does often travel beyond your own home. And it is one of the most biggest causes of RF pollution in residential areas.


http://www.ukqrm.org.uk/

The FCC in the USA typically does testing on equipment to certify that it produces below an acceptable level of RF noise or EMF, but fights an uphill battle of sheer numbers. The RF produced by computers and other digital equipment alone is hard to predict and the products are shipped by the millions.
-DFB

Subject: I have a black cat.
Believer: Black cats are bad luck.
Non-believer: It's just a cat.
Crackpot: Black cats are part of the New World Order government conspiracy.
Skeptic: I can test if black cats are more or less lucky than another cat.
Cynic: You only have a black cat to gain power and prestige.

https://www.youtube.com/watch?v=t9iIf4tFoyE

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#7
Also some items sent for testing are filtered. But the item supplied to the public are not, as it's cheaper to make rubbish.
Look at the ARRL site for the issues that electrical items are causing American radio amateurs due to unwanted radiation of rubbish.
The electrical noise floor across all of our radio spectrum is increasing. The Radio Society of Great Britain recently released details of how the VHF noise floor had showen a 12 db gain over recent years. This means where someone could use 10 watt transmitter to get above the noise over a certain area. Now that same coverage would need a 150 watt transmitter.
There is also some confusion in definitions when looking at what people are saying about the use & coverage of these EMF meters which shows a lack of basic knowledge & thus an inability to use them.
A radio wave is a sine wave that travels at 300,000 meters per second.
[Image: avatar_0b7cc905584e_128.png]
The frequency Hz, Mhz, GHz etc is about how many waves there are a second, the more waves the shorter they are.
This allows us to use a very simple calculation to work out the wave length of the wave.
The Wavelength of a radio wave is a measurement along a horizontal line between two points on the sine wave.
The sine waves start in the Hz & can be sound or radiated radio waves. At Hertz, the radio waves are Ultra Long Waves with lengths of thousands of Kilometres. What Americans call AM radio is Medium Wave & there the wavelength is a few hundred meters long. Then there are Short Waves of 10 meters of less. VHF & UHF get smaller & finally we end up in the Microwaves where the length of that measurement across the sine wave is a few Millimetres in length & that gets us into the light spectrum.
Microwaves are not different to RF. Microwaves can be RF. That is what a microwave oven is, an oven that cokks using short radio waves. It is simply a term used to describe the length between two points on a sine wave where the measurement is VERY short.

We all believe in something greater than ourselves. Even if it's just the blind forces of chance. Ambassador G'Kar.
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#8
(11-19-2016, 11:00 AM)Darkforeboding Wrote: The detector might not pick up EMF interference when held at one angle but suddenly pick up EMF when held in the same place at another angle. If a researcher doesn't understand this they might think that a phenomenon is suddenly appearing and disappearing.

It is called Polarity. In general if a receiving antenna is out of polarity by 90 degrees. That is if one is say vertical & the other horizontal then 3dB of signal will be lost.
3dB is 50% of the signal.

We all believe in something greater than ourselves. Even if it's just the blind forces of chance. Ambassador G'Kar.
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