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 3. GQ EMF EF Meter RF Spectrum Power Analyzer
 How to sweet talk your GQ EMF-390

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rfrazier Posted - 02/07/2020 : 14:02:56
Hi all, my name is Ron Frazier. I'm new to the forum, but I wanted to share a bunch of info I've been accumulating about taking EMF measurements and about using the GQ EMF-390.

I just got my GQ EMF-390 meter and have spent a number of hours playing with it and testing it. I like it, and it's a good meter, but you gotta learn to sweet talk to it. In other words, you have to invest some time in learning how to use it properly. I am just a user. I have no official affiliation with GQ.

I am in training with the Building Biology Institute to become an Electromagnetic Radiation Specialist (EMRS). I'm speaking for me, not for them though. But, I mention it because I've spent a lot of time studying EMF meters and EMF measurements lately. That point of view affects how I view these instruments. Here are some things that I believe will help you use your instrument.

01) This is a consumer grade instrument, which they say in the FAQ, not professional grade. So, balance your expectations accordingly. However, that doesn't mean it can't be useful to a professional, as well as consumers.

02) The quick start guide is just that. Do read it. But realize that's only the beginning of your journey. Download the full user guide, which is a PDF of many pages, and go through that. At least their documents are written in mostly good English, as opposed to Chinese-English. As a bonus, the quick start guide is in color.

03) Learn how to operate the controls. This may not be obvious at first. Once you've gotten used to them, it will seem much more natural. While the buttons don't have printed labels on them, they do have shapes molded into the plastic, which you can see if you look.

Some buttons do different things depending on whether you press and release, or press and hold.

If you have the meter facing you, in landscape (wide) mode, and the buttons and model number are on the right:

The TOP button, which they call S4, can: check the battery when powered off, power the unit on and off, activate the menu system when powered on, select items in the menu system, and sometimes change things in the menu system.

The BOTTOM button, which they call S1, can: back you out of most menus, activate a menu to select the different screens of the device.

So, an effective technique to go through menu settings is: press the TOP S4 button to get into the menu, press one of the middle buttons to navigate, press the TOP S4 button to select an option, press the middle buttons to change an option, press the TOP S4 button to finalize your answer. Sometimes, pressing S4 will change an answer, so make sure the screen says what you want when you're done. You can then get out of the menu system with the BOTTOM S1 button. You can, if you wish, go back into the menu, and examine each setting without changing it to verify the settings.

When not in a menu, the middle S2 and S3 buttons do various things, like allowing you to alter units, switching from EMF (magnetic and electric field) mode, to RF (radio field mode), moving a cursor, zooming in or out, etc. You kind of have to play with these buttons on each screen. Sometimes they do something different if you hold them down.

04) IMPORTANT, learn how to point the meter. Inexpensive meters have single axis sensors which are directional, and they care about how they're oriented in space. This meter has a 3 axis magnetic field sensor, which they label on the screen as EMF. So, you can turn the meter any way you want to read magnetic fields. BUT, the electric field sensor (EF), and the radio field sensor (RF) are directional. If you're pointing the meter the wrong way, you may get wrong readings, or no readings.

I have rewritten this section of text several times, as my understanding of the antennas in the GQ EMF-390 has changed. I will share my best understanding, but the reception pattern of the meter is not totally clear. So, you may have to point and orient the meter in various different directions and rotate it in various orientations to find the way you get the maximum signal in any given situation. See the EMF-390 How Is General RF Antenna Oriented link below for additional information.

Antenna placement is documented on page 5 of the quick start guide, as well as in the PDF. Nevertheless, it bit me and caused me to lose some sleep one night fretting with it. I haven't done much with the EF sensor, but I've been working with RF. This meter may not work like you expect, but it will work if you treat it right. My Safe and Sound Pro II meter and my Cornet ED88TPlus will both respond to most RF signals if you are holding the meter in front of you in portrait mode (vertically), with the display facing you, and the RF source, like a cell tower, out in front of you. This meter may not respond optimally that way. With this meter, you would be pointing one of its sensors up into the sky. As I understand it, this meter has a 2 part general RF sensor. One part would respond to a source out in front of you if holding in portrait mode in front of you. The other part would respond if pointing the curved surface of the meter toward the transmitter. The first descriptions below are based primarily on the latter mode. Then I talk more about the former mode.

Imagine this meter is a small airplane. Place the meter flat on a table with the buttons and label near you and the display face up. The near end with the buttons is the tail. The far end where the propeller of a plane would be (its nose) is the front. On the GQ EMF-390, this surface is curved. The far end, curved surface, of the meter is where one part of the RF sensor is pointing. If there were a cell tower, for example, out in front of your table, you could get a reading on it. In terms of an airplane, pitch means to bring the nose up or down. Yaw means to slide the tail left or right, turning without changing the bank of the wings. And roll means to bank or tilt the wings left or right. Rolling left or right is (sort of) what a race car does going around a sharp turn on a banked track.

For lack of better terms to use, this meter CARES about pitch, roll, and yaw. If you pitch the nose of the meter up or down substantially off the line to the source, you will get bad or no readings. If you yaw the meter left or right substantially off the line to the source, you will get bad or no readings. But, that's not all. The meter cares about roll too.

Just to be clear, ALL single axis meters care about these things. The Safe and Sound Pro II is RF only with a single axis sensor. The Cornet ED88TPlus has EF, MF (or EMF), and RF sensors, all of which are single axis. All these meters will give bad readings if they're pointed wrong.

All radio waves move outward from the source. But they also have orientation in space. They may be oriented vertically as they move outward. This is called vertical polarization. This usually requires a vertically oriented antenna to receive well. They may be oriented horizontally as they move outward. This is less common and is called horizontal polarization. This usually requires a horizontally oriented antenna to receive well. There are even some sources which are circularly polarized. Some cell towers have vertically polarized antennas. Some cell towers have both vertically and horizontally polarized antennas.

If you have a cordless phone, you could test your meter with it. At least in the US, almost all cordless phone base stations radiate a strong signal all the time. One you should not stay around. Remember that verbiage on the box that says it will work 900 m away? But you don't sit 900 m away do you? I have decommissioned all my cordless phones. But, they make a great little personal microwave beacon for testing. Just plug in the cordless phone base station to a power source, set it several feet away, and start taking readings. It should put out a continuous signal. On meters with a histogram mode or moving graph mode, like the GQ EMF-390 or the Cornet ED88TPlus, you should see a continuous signal or a continuous string of pulses. Remember to unplug the cordless phone base station later if you're not using it. You can also test the meter pointing it at a cell tower, etc.

So, what this all means is, assume you have pointed the meter (curved surface) up and down (pitch) to line up with the source, and you have pointed the meter left to right (yaw) to line up with the source, and it's lying flat on the table (or in your hand) with the display up (roll), you STILL may not get a good reading. This was my experience testing with the cordless phone base station. I had to roll the meter 90 degrees, so the display was facing to my left. THEN, I got a strong and consistent reading.

At that time, I didn't know that the meter also had part of the sensor facing toward me and away from me if I were facing the display. So, while I was testing with the cordless phone, I may have been getting reflections going into the 2nd part of the sensor and not to the direct line of site to the cordless phone. In the case of measuring a cell tower, you may get a good reading if facing the cell tower and holding the meter in portrait mode in front of you with the display facing you (ie curved surface facing up to the sky). But, as I mentioned above, you should rotate the meter all around in different directions to find out which way you get the strongest signal.

You may have to do similar gymnastics with the Cornet ED88TPlus and other meters. This is true with any meter with single axis sensors. This may make the display hard to read because it's facing away from you.

Also, be aware that, unless you're all alone in a field with nothing but you, the source, and the meter, you will encounter reflections. If there are buildings or mountains or hills around, or if you are in a car, or in a room, the RF signals will reflect all around. This may make it hard to determine the best way to point the meter. If you know where the RF source is, either point the front curved surface directly at that and experiment with rolling the meter between horizontal and vertical orientation in both directions; or hold the meter in front of you in portrait mode with the display facing you and you facing the source and experiment with rolling the meter between landscape and portrait mode in both directions.

Also, some meters, while being directional, still receive signals from multiple directions. They may receive signals from behind where they're pointed. Or they may receive signals from 360 degrees around the sensor in one plane but not in another plane. So, you may be measuring signals from multiple sources at the same time without knowing it. The meter will show the strongest signal it's getting, whether that's what YOU are looking at or not. I'm not sure what these characteristics are for the GQ EMF-390, but it definitely will receive from multiple directions.

Let's talk about actually taking readings and what they mean. What I have observed with three different meters, is that they all read differently. This is normal, for reasons described below. But, what it means for me is that it's hard to compare the readings of different meters. What it also means for me is that I will be using the meter that most closely aligns with the standards I'm referencing to gather my numbers to quantify exposure.

Taking EMF readings, especially RF, is quite complicated for several reasons. Note that putting an RF meter closer to a test object than a few feet is not accurate. See my paragraph about near field / far field below. The Building Biology Institute h**ps:// h**ps:// is at the forefront of research and training into EMF harm. Low / High recommendations on these meters usually are way too lax regarding radiation limits. Building Biology Institute recommendations, based on world class health research, can be found here: h**ps:// and here: h**ps:// . These show very conservative numbers. For sleeping areas, and especially considering sensitive and ill people, their maximum recommended limits are: RF (Radio Frequency): <= .1 uW/m^2 - 10 uW/m^2 (microwatts per meter squared); MF (AC Magnetic Field): <= .2 mG - 1 mG (milligauss); EF (AC Electric Field): <= .3 V/m - 1.5 V/m (volts / meter). These numbers are VERY hard to achieve in a modern environment. Even within these ranges, Building Biology standards recommend additional remediation when possible. Note that, when your meter reads RF 1000 mW/m^2 (milliwatts per meter squared), that's the same as 1,000,000 uW/m^2 (microwatts per meter squared). Be aware that many meters will SWITCH units on the fly, and this is very confusing. On the GQ EMF-390 I (personally) recommend setting the RF units to mW/m^2 all the time and not using auto unit switching mode. Common units are uW/m^2 and mW/m^2 for RF. But you may also see mW/cm^2 or others. If you see mW/cm^2, for example, you must multiply by 10,000 to get to mW/m^2. Then, you must multiply AGAIN by 1000 to get to uW/m^2. So, if your meter reads 1 mW/cm^2, this is 10,000 mW/m^2, or 10,000,000 uW/m^2. Here's a handy page with EMF and RF unit conversions. h**ps:// And here is a useful RF unit conversion chart. h**ps://

To make things worse, all modern communications systems use pulsed radio waves. These pulsed waves affect biology more than continuous waves. Let's say a WiFi system is sending 1000 Mbps (megabits per second) of data. So, data bits, 1's and 0's, are occurring at a rate of 1 Gbps (gigabits per second) or at a frequency of 1 GHz (gigahertz). However, these pulses are not continuous. They may go for a while, in a group, then stop. Then do that again, and again. The number of pulses in each group and the time between will be variable and unpredictable. The time between these pulses may be as little as 1 nS (nanosecond) or .001 uS (microseconds). I have a professional grade Safe and Sound Pro II radio meter from h**ps:// . It costs around $ 400. It's sensor has a very fast response time compared to others, but it is still only 5 uS (microseconds). So, even this meter would have to average 5000 or so of these fast data pulses to take a reading within the response time of its sensor. Other less expensive meters often are even slower to respond. Note that the DISPLAY only updates about twice per second, but calculations are going on much faster in the background. My Cornet ED88TPlus meter has a response time of 100 uS. That means that this meter would have to average about 100,000 of these fast data pulses to take a reading. The RESULT of this, is that most inexpensive meters will, usually, but not always, UNDER REPORT the RF reading. My Cornet routinely reads 2X - 6X lower than my Safe and Sound Pro II (for peak readings) when they are sitting side by side, although, occasionally, the Cornet reads higher. So, if an inexpensive meter tells you that you have a number for RF that is considered high according to world class standards (not the legend on the meter), and assuming the meter is far enough away from the source; you probably have an even bigger problem than you think. The actual reading is probably even higher. Note that the AVERAGE of these short pulses has much less meaning in terms of biology than the PEAKS. The Building Biology recommendations mentioned above are PEAK readings for RF.

Way back in the 1960's as an example, it would have been much simpler to measure RF. If you exclude military, nautical, and weather radar, and things like police radio, your basic exposure would be from AM radio, FM radio, or TV signals. There really weren't any wireless transmitting devices at home, or even near most homes or shopping centers. The signals from AM, FM, and TV were analog. They were not pulsed digital as they are today. The signals were relatively consistent in frequency, and strength. So you pretty much point a meter at it, take the average strength and frequency, and go with that. That's not true any more. If a radio wave today is pulsing at up to a billion times per second or more with information, in an unpredictable manner, with unpredictable gaps between the pulses, how does a meter, which may only sample the signal every several thousands of those pulses, take that information and quantify it and put it on a display that only updates a couple of times per second? Sorry for that convoluted sentence. But, I think you can see that there could be hundreds of ways of getting from the raw data to what you see on the screen. This is one reason no two meters ever read the same. So, as I said above, for quantifying readings into a number, I'm going to gravitate to a meter that's most compatible with the Building Biology way of thinking about things.

Also note that, if you're reading electric fields, you should stay a few feet away from the meter, as your body will alter the reading.

It also matters whether you are in the near field or the far field of the signal. The following is not relevant for towers or other far away transmitters at high frequencies, but would be relevant if you were trying to measure next to a phone, tablet, or router, etc., or even for towers at lower frequencies. All these type of meters are designed to measure "far field" RF radiation. To be in the far field, you must be 3 wavelengths from the source. Wavelength varies inversely with frequency. Higher frequencies have shorter wavelengths. h**ps:// Here's one of many wavelength calculators: h**p:// If you run the numbers for a .6 GHz (gigahertz) or 600 MHz (megahertz) signal for example, 3 wavelengths is 4.92 ft. Therefore, if the phone is transmitting on a 600 MHz channel, your meter would have to be 4.92 ft or ~ 5 ft or more away to get an ACCURATE reading of RF (within the meter's limits). Signals to the cell tower may routinely be in this frequency range, although they are usually higher frequencies. If the phone is transmitting WiFi or BlueTooth, which are around 2.4 GHz, 3 wavelengths is 1.23 ft or ~ 15 in. So, if, and only if, the phone is known to be transmitting ONLY at that frequency, you could get an ACCURATE reading of RF at 15 in or more away. The same is true of WiFi tablets or other BlueTooth devices. Any closer than this and the numbers will not be accurate. BUT, if the tablet is connecting to a cellular network, 3G, 4G, or 5G, you must assume the lower frequency and the longer wavelength. 5G cellular is not the same as 5 GHz WiFi. Now, it is certainly true that the TREND of the signal strength increasing as you get closer to the phone is true. It is certainly true that the actual signal strength when holding the phone next to your head is MUCH MUCH higher than what you will measure at 5 feet away. It's just that you cannot get an accurate number when closer than that if the phone is running on 600 MHz.

So, for me personally, for getting numeric readings for RF, the Safe and Sound Pro II is a better choice, since it's designed with Building Biology standards and methods in mind. I do believe the GQ EMF-390 will be useful for measuring EF and MF (or EMF) fields, although I still may have to get professional grade instruments for that.

But I DO believe the GQ EMF-390 will be useful to me for DETECTING RF sources and for VISUALIZING RF sources. The RF Browser is the place I'll probably spend most of my time. This is a very good tool for visualizing the radio pulses going through the air. Also, I have modified the alarm settings to more closely correspond to the Building Biology Standards. This makes the meter a very good and fairly sensitive RF detector. I've set the RF alarm to occur at .010 mW/m^2 or 10 uW/m^2. This is at the high end of the "Slight Anomaly" category on the Building Biology chart, where remediation is recommended where possible. I set the MF (or EMF) alarm to occur at 1 mG, which is also at the high end of the slight category. I set the EF alarm to 2 V/m, which is just a little above the slight category. The actual number I wanted was 1.5 V/m, but the menu doesn't allow that. Be sure to write down the original alarm settings before changing them or you'll have to reset the entire meter to get back to the original settings.

With these settings, once the meter was properly pointed at the source, properly oriented, and far enough away, I was able to detect, and get alarms for, a cell phone 5 feet away from the meter, any time I activated wifi or sent or received a call. Note that the readings were well OVER my alarm limit levels. This should tell you something about how much microwave radiation a cell phone puts out. So, I believe this meter will be a valuable tool in helping me detect unknown sources that are reasonably close to me in a space.

Bottom line, this seems to be a good meter if you understand its limitations and treat it properly. If you treat it wrongly, it will give you bad readings in return.

Here are some other posts with different info you might find
interesting. My posts are under the name rfrazier.

EMF-390 How Is General RF Antenna Oriented

5G Images

near field questions

EMF-390 - Help me, i am scared with this.

Safe RF Range

Panasonic portable phones

EMF-390 and Wi-fi/router

Hope it helps.

7   L A T E S T    R E P L I E S    (Newest First)
rfrazier Posted - 08/05/2020 : 18:34:55
EMFDev, I am still in doubt as to the exact orientation of the RF antenna. Can you post a photo of the correct way to hold the meter when facing a cell tower so I get the maximum RF reading assuming the cell tower has vertically polarized antennas? Thanks. Ron
Livelyite Posted - 07/22/2020 : 16:41:09
As a newly diagnosed EMF Hypersensitive, and owner of new GQ390 meter, I appreciate the amount of effort you put into creating this post. Thank you. Very helpful! In the process of figuring out how to wire my home for Ethernet... can't happen fast enough. Have hired a consultant who knows ethernet, and I know how to pull wires and install boxes. The more I reduce my exposure, the less pain I have in my body, and the ore energy I have.
Bill D. Posted - 06/27/2020 : 11:45:01
ZLM, these are really interesting and impressive tests!
ZLM Posted - 06/01/2020 : 10:28:23
GQ EMF-390 RF pulses speed testing:
GQ EMF-390 RF Browser:
GQ EMF-390 RF Frequency Response On Off comparing:
EmfDev Posted - 02/10/2020 : 11:40:01
Thank you for your feedback. When the 390 is flat on the surface with the buttons close to you face up, the RF antenna is located at the right side of the curved edge facing front/up/back/down. And the EF antenna is on the left side of RF antenna.
rfrazier Posted - 02/09/2020 : 17:36:41
Hi Bill D., You're welcome. Glad to help. Ron
Bill D. Posted - 02/09/2020 : 16:48:28
Thank you for writing this informative analysis. When I selected the GQ EMF-390, I realized that I was trading some accuracy for versatility. I use the 390 to detect and measure low frequency electric and magnetic fields especially around power lines (which are all near field measurements at those wavelengths). There are better instruments to do that, of course, but it is hard to find a meter with the same range of measurements. It functions as an all purpose meter.

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