GQ Electronics Technical Support Forum


GQ Electronics Technical Support Forum
Home | Profile | Register | Active Topics | Members | Search | FAQ
Username:
Password:
Save Password
Forgot your Password?

 All Forums
 GQ Electronics Forums
 3. GQ EMF EF Meter RF Spectrum Power Analyzer
 EMF-390 and Wi-fi/router
 New Topic  Reply to Topic
 Printer Friendly
Author Previous Topic Topic Next Topic  

3amado3

USA
3 Posts

Posted - 05/21/2019 :  08:25:05  Show Profile  Reply with Quote
Just got my new toy and am trying to learn what its telling me!

For the most part my main concern is testing the router (trying to limit wi-fi exposure). Im testing it in the all-in-one mode and if I stand right next to the router the RF hits around 2000 mW/m^2. If I move 5 feet away it drops to the 15mW/m^2 range. If I go directly up a floor its all the way down under 1mW/m^2 for the most part. In the bedrooms another floor up its about .001.

Is this telling me there is basically no RF radiation reaching the bedrooms? But how come I still get a couple of bars on my phone for wi-fi reception? Or more specifically a wi-fi analyzer app lists the signal at about -60 dBm (it gets down to -15 dBm right next to the router). Is there some other type of wave other than the RF radiation that I should also be considering/measuring if I want to test the wi-fi safety of my house? Clearly it's reaching the bedrooms but the 390 doesn't say that.

Second question, which column in the below link translates to the mW/cm^2 and mW/m^2 that I have the option of displaying in the 390? Is it literally mW/cm^2 and W/m^2. I was looking elsewhere for safe levels and things were listed in V/m and uW/cm^2 and some of the numbers seemed strange when I converted to what the 390 was saying so I just wanted to be sure. (and the card that came with it switches between uW/cm/^2 and mW/cm^2 for listing it's levels which seem confusing)

h**p://www.hypercable.fr/images/stories/Conversion_Chart_dbm_v_m.pdf

Third question, if Im just trying to sort out the RF (we live in the suburbs away from towers, just want to measure the wifi impact), which is the best view to use? They seem to give different results. Standing a couple feet from the router the All in one view says about 30 mW/m^2. Or .004 mW/cm^2 (that setting seems pointless, it barely registers even right next to the router). Then if I switch it to RF Browser there is a number in the upper right corner that is continually changing and in the 30mW/m^2 range, but also a number in the upper left corner that changes less often and in a higher mW/m^2 range typically (say 50+). Then if I switch it to the RF Spectrum, I have no idea what this is saying. I have it set to the 2.4-2.5 Ghz but it doesnt list numbers in mW/m^2, it just has a Chn number in the upper right, dBms at the bottom and continually changing pWs in the upper left.

Sorry for the long post, Thanks for any help!

(shocking how much RF baby monitors give off, those have been shut down.)

Edited by - 3amado3 on 05/21/2019 09:39:48
Reply #1

EmfDev

642 Posts

Posted - 05/21/2019 :  09:12:15  Show Profile  Reply with Quote
Hi 3amado3,

1. The WiFi strength gets much weaker with distance. Cellphone WiFi antennas are designed to be more sensitive to WiFi signals than the 390. If you specifically wan't to chech wifi signals, use the 2.4-2.5GHz band in RF spectrum.

2. I don't quite get what you were asking and there's no link.
1000mW/m^2 = 1W/m^2.
1mW/cm^2 = 1000mW/cm^2.
10,000 mW/m^2 = 1 mW/cm^2 = 1000uW/cm^2

3. In RF Browser, the upper left corner is the highest reading within the whole screen. The whole screen covers reading between 1-12 seconds depending on your settings. The upper right corner is the current reading that's why it changes a lot because RF is not constant. AllInOne Mode should be best, you can also try to set the RF Sensitivity under User Settings to Sensitive.
Go to Top of Page
Reply #2

3amado3

USA
3 Posts

Posted - 05/21/2019 :  12:13:03  Show Profile  Reply with Quote
1. ok i set RF Spectrum to measure in Watts instead of dBm, so at least now it is saying something. But the upper left corner is in pW (sum) and constantly changing (so it's hard to read), but always in the 400 range no matter what I point it at. The upper right is in mW/m^2 and also constantly changing, but seems to always be about about .2 mW/m^2 no matter what I point it at, and the bottom of the screen is also in pW and pretty much always says .3 or .5.

I don't know how to translate pW into any of our other metrics, but the mW/m^2 is nowhere close to the readings i see on the other screens, it is much lower. I also changed the RF sensitivity to Sensitive (I had it on Standard due to a response I saw elsewhere in the forum) - but changing that really didn't do anything for my results.

2. Sorry, i added the link above. Your conversions help. So the link doesn't list mW/m^2, and W/m^2 is different than I thought above as your formulas showed me (although I think your second formula needs adjusting).

3. ok, i had it set to 3 seconds, that makes sense. Although you say here that all in one mode should be best, but in #1 above you said RF spectrum so I'm still confused. If it's RF spectrum then I still have the issue of the numbers not making any sense to me as noted in #1. But knowing that cell phones are more sensitive than the 390 at least tells me why I get a signal in the bedrooms when the 390 says that nothing should be making it there.

Go to Top of Page
Reply #3

EmfDev

642 Posts

Posted - 05/21/2019 :  13:13:09  Show Profile  Reply with Quote
1. The upper right is the power density of the peak (from dbm to power density). And the powers are corresponding to the density, same values but different units. The sum is the total power of all the frequency range. The bottom number is the minimum power detected within the range.
In dBm mode, the Chn: in the upper right tells you the channel bandwidth and channel spacing of each channel.

2. sorry the second one 1mW/cm^2 = 1000mW/m^2.

3. Sorry I thought you also cared about cell phone signals. But for just WiFi, the 2.4-2.5GHz spectrum is the best to use. The RF Spectrum 2.4-2.5GHz is for measuring signals like bluetooth, wifi, microwave, etc. You can probably see the graph in the Spectrum jumping too fast and high when you're close to a router that's because WiFi signals are transmitted fast and in a very short period of time. So on the upper right where it says mW/m^2, it should at least go up or down depending on the signal strength.

Go to Top of Page
Reply #4

3amado3

USA
3 Posts

Posted - 05/21/2019 :  19:19:22  Show Profile  Reply with Quote
Thank you for the quick responses! I tried to learn about power density and translate it into numbers I would understand, but that didn't work out :)

Instead lets focus on just one thing - it sounds like Spectrum RF is what I should focus on, so here is my issue. In the pics I will now attach I am standing about 3 feet from my router. The all-in-one view shows about 32 mW/m^2, that number makes sense to me. The Spectrum view shows .045 mW/m^2, that does not make sense to me. Is there some setting I need to adjust or am I just not understanding something?

(sorry - I don't know how to make those pics smaller!)

One thing that just dawned on me, putting it in math terms, does the Spectrum view basically represent the PDF of a distribution (just showing a tiny point in time) and the All-in-one view is like the CDF with it being more grouped up? If so, is there a way to look at the Spectrum view "grouped up" since .04 mW/m^2 doesn't really tell you much when you are reading what levels are safe or comparing to the bulk of the discussions on the topic.

Image Insert:

2066945 bytes

Image Insert:

1827824 bytes

Edited by - 3amado3 on 05/22/2019 07:41:19
Go to Top of Page
Reply #5

EmfDev

642 Posts

Posted - 05/22/2019 :  09:08:20  Show Profile  Reply with Quote
In the all in one mode, the range of detection is .24-10GHz but in the spectrum mode it's only 2.4-2.5GHz. Also each channel is only 812kHz bandwidth.

The spectrum lets you see in which frequencies some RF transmitter operates. And how tell you about how strong it transmits the data. the 0.04 is the density of the channel with the triangle.
Go to Top of Page
  Previous Topic Topic Next Topic  
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
GQ Electronics Technical Support Forum © Copyright since 2011 Go To Top Of Page
Generated in 0.12 sec. Snitz Forums 2000