FAQ

1) How to hold the CORNET meter for measurement?

The CORNET meter has three internal sensing antenna built in to measure the received signal; the user should not cover or block the sensor area of the meter while measuring. The location of the sensors is indicated on the meter's back silver label. The CORNET meter is a single axis meter; please rotate the meter to get the maximum reading direction and follow that direction while measuring. (Only a single axis meter can find the direction of the signal source.) The meter has three operation modes (RF, LF Gauss, and LF Electric field); please follow the directions in the picture below while doing the measurement.



2)What is the best measuring distance between the RF source and the meter?

The majority of RF safety standards required a minimum measurement distance of 1 meter or 3 meters from the source of the RF signal; otherwise, the meter will become overloaded (such as RF transmitter or WIFI router which radiates very high RF power from its transmit antenna).
If the meter is placed too close to or right next to the transmit antenna, the frequency counter feature of the meter will also get overloaded.

For mobile phone antenna tower measurement:
The area between 50 and 300 meters from the antenna tower is the one with the largest radiation risk
When the distance was extended, the RF radiation rapidly reduced ( by distance square)
The RF transmit power to the transmit antenna on the tower also affect the radiation level as well.

Radiation power density (mw/m2)= RF transmit power(mw)/4πR2     where:R is distance from RF source
 
*A highly recommended resource on cell tower radiation may be found at: http://www.buergerwelle.de/assets/files/workshop on cell tower radiation.pdf
 

3) Accuracy of the meter?

Each CORNET meter is calibrated in our USA lab using certified test equipment before being shipped to our customers.   
We also compare the meter's reading to that of an industrial standard certified professional EMF meter from companies like
Narda and Smartfield meter to make sure it is correct.  The meter store the Calibration data inside the meter's memory, therefore it is not required to re-calibrate the meter from time to time.


2.4ghz900mhz5.8Ghz


antenna response

4)What is the Maximum frequency the ED88TPlus meter can operate?

The ED88TPlus5G and ED88TPlus2  meters have an 8GHz specification, but they are found to  work up to 11GHz with reduced sensitivity.(Uncalibrated) as a detector purpose, such as   detecting a  microwave motion sensor for LED light control detection.   (For better sensitivity the ED85EXPlus meter with LPDA1810 external antenna unit is recommended)

* Remember that the air loss of a high band microwave signal is very large; most devices at that frequency operate at a signal level of -80dBm to -100dBm; you may need to place the meter very close to the signal source to detect it.


10Ghz labhb100


5)What is the Frequency counter function of the ED88TPlus series meter ?

   Real time Frequency counter display

The CORNET ED88TPlus series meter is currently the only meter on the market with a built-in frequency display function. 
The ED88TPlus series meter's Frequency display function is a real time frequency counter; the meter measures both the RF signal level and the frequency of the received signal at the same time, down to each  pulse/burst level
( the pulse/burst can be as short as 100usec).

The ED88TPlus5G frequency counter operates up to  4.2GHz, covering all 5G mobile network frequency bands  (except the millimeter wave band), while the ED88TPlus2 and previous models of CORNET meters operate up to 2.7GHz.  

Based on the frequency of the signal, the user can determine the source and type of the RF signal.
 (for example: Wifi use 2.4GHz, DECT phones use 1.9GHz, 4G cell phones use 1.7GHz-1.9GHz, cordless phones, IOT devices use 900MHz, and 5G mobile network uses 3.5GHz....)   Once the signal source type is known, it is very easy to find a way to reduce the  RF radiation level. 
 (*A minimum signal level is required to correctly detect the frequency of the signal.)


 
6) The difference between RF power (dBm, mw) and RF power density (mw/m2) ? 

-The dBm or mw is the unit of the received RF power.   (0dBm=1mw)
-The mw/m2 is the unit of the RF power density which is related to the RF field strength. 
-The RF power density (mw/
m2)  is the received RF power (mw) divided by the area (m2) of the  the effective area of the  meter's receiving antenna.

For example:  tne meter's antenna received the RF power of -25dBm,  after divided by the effective area
                        of the receiving antenna (m2) we got the power density or field strength of  1.8mw/m2
 

The effective area of the receiving antenna is different for different antenna or meter design.

If you are measuring RF field strength you use the unit of RF power density (mw/m2)
If you are measuring received RF power you use the unit of RF power (dBm)
*most of the RF engineer uses dBm because the RF transmitter output, antenna loss, on air loss, distance loss, and frequency loss etc., ... are all specified as  dB
or power of  dBm. ( the meter's  received   RF power is the RF source tranmitted power minues all these loss).

 


7) Compare Frequency counter to the Spectrum Analyzer? 

    Spectrum Analyzer problems in modern digital RF environment


The modern digital RF signal utilized in mobile phones, Wifi, and new wireless devices is a pulse/burst kind of RF signal. It transmits signals in extremely short bursts but does not send any signal in between the pulses/bursts; the RF pulse/burst has a very high signal level while bursting, and practically little signal during non-bursting time. The classic scanning method of Spectrum analyzer has a very sluggish scanning speed because it scans each frequency of the covered frequency spectrum step by step. It displays the frequency when the incoming signal  frequency is matched with the spot scanning frequency of the Spectrum analyzer.
 It is a "Hit or Miss!" procedure.  It is fine for old continuous wave analog RF signals, but not for modern digital RF pulse/burst type of signals.


The classic scanning type of Spectrum Analyzer simply cannot record the receiving on and off RF burst in time (It will take several seconds to scan from low frequency of spectrum to high GHz of spectrum in old scanning type of Spectrum analyzer). Because the on-air RF signal is asynchronous to the spectrum analyzer's scanning operation, the Spectrum analyzer will miss burst signals most of time.
The only method to avoid the issues is to repeatedly scan the full frequency spectrum again and again then overlay the findings in the goal of obtaining a complete image of the spectrum of the signal received. Most of the time, this is not very effective because the digital RF transmitted signal bursts are time dependent and never repeat themselves like continues wave analog RF signals, If the Spectrum analyzer fails to capture it at the scanning frequency in time, the RF burst signal is gone and the Spectrum analyzer will never able to capture it again and show the frequency of it.


To solve the problem,  modern Real-time Spectrum Analyzer captures sections of the frequency spectrum all at once and then display the spectrum using digital signal processing methods, but it is very expensive and bulky equipment,  the bandwidth of the section of frequency that the real-time Spectrum Analyzer can capture each time currently is also very limited.
 

  

spectrum analyzer

 
The slow scan speed of Spectrum analyzer can not capture the fast on/off pulse/burst of the modern digital RF signal in time. 
The real time frequency counter  in the ED88TPlus series of meter  is the best solution for the modern digital RF signal problems.


The ED88TPlus5G meter captures signals at a rate of 25000 samples per second, allowing it to record digital RF signal  pulses and bursts as short as 100usec. Each pulse/signal burst's level and frequency are recorded in real time. You always get the correct signal level and frequency of the signal pulse/burst.
 * (The frequency counter circuit requires a certain minimum signal level to function properly.)


8) 5G mobile frequency indicator? 

   5G mobile frequency frequency indicator
=5G=

The ED88TPlus5G meter frequency counter display supports frequencies up to 4.2GHz. The meter automatically detects the 5G mobile network frequency bands signal and displays a 
=5G=  mark on the display to indicate the detection of the 5G mobile network frequency. (5G channel n5, n71, n77, and n78)
 
 (*A minimum signal level is required to correctly detect the 5G signal.)

5G indicator

9) How to use the ED88TPlus5G to measure the 5G signal?

The 5G mobile network can transmit data at super-fast speeds.  However, it consumes a lot of bandwidth from the system, limiting the number of services that can be provided at the same time. There are two types of 5G network systems: SA (standalone) and NSA (no-standalone).   The SA system employs a pure 5G network system and frequency.  The NSA system combines the older 4G-LTE system and frequency with the new 5G network system and frequency as a hybrid system.

Because the SA system is very expensive, 99 percent of the world's 5G mobile networks are now using the NSA 5G system..

When a mobile handset attempts to connect to a 5G antenna tower-based station, the NSA 5G system uses the older 4G-LTE frequency band for the protocol handshaking phase. and it only transmits super high-speed data using the 5G system/frequency band during the 5G data download phase. It is done dynamically.  If the based station decides that the 5G signal is not good enough or is too busy, the NSA 5G system may not use the 5G system/frequency at all in the data download phase of transmission. Instead, it may use the older 4G-LTE system/frequency for data download phase transmission. As a result, the 5G network signal will not be visible in the NSA 5G system all the time. 

You may not be able to detect the 5G signal/frequency in front of the 5G antenna tower in the NSA 5G system, unless someone in the area is using the 5G phone talking to the antenna tower base station, and is in the 5G data download phase using the 5G signal/frequency.

The ED88TPlus5G has a built-in frequency counter and 5G frequency indicator that supports all 5G frequency bands*. It will detect and display the 5G signal frequency when the NSA 5G system transmits the 5G signal with the 5G frequency during the 5G super high speed data download phase.

Other meters without a frequency counter function will not be able to tell you whether you are measuring an old 4G/LTE signal or a new 5G signal.
 
*except the millimeter wave band


10) Statistical Data window of the received RF signal in ED88Plus5G ?

Modern digital RF signals are pulse/burst signals with a very high on-time burst signal and almost no signal in  non-bursting time. It is different from  the traditional continuous wave analog type of RF signal.  
Today, the majority of wireless devices use digital RF signals.


The "Average value" of the signal level used by the  transitional EMF meter or RF power meter to display the level of a continuous wave RF signal does not work well for modern digital RF signals, because the digital RF signal changes on and off so fast that the "average value" can no longer show the actual behavior of the signal measured.

The majority of the professional RF power meter is now operate in peak power meter mode. It displays the peak level of the RF pulse/burst signal. EMF safety research is also expanding into the digital RF field.



Is the peak value is good enough for the modern digital RF signal measurement?

Since the ED15 meter, the CORNET meter has been a peak power meter. But, is the peak value reading adequate for modern digital RF measurement? The answer is no, not really!     The modern digital RF signal burst is changing so fast that you can have several thousands of RF burst signals coming during the standard 0.5sec LCD screen update period. A single peak value of an RF pulse/burst signal among thousands of pulse/burst signals cannot represent the true behavior of the received signal.   It required Statistical data from all of these thousands of pulse/burst signals to show the actual behavior of the received signal.

(* Why is the screen updating time 0.5 seconds? It is the shortest amount of time that the human eye can keep up with the fast-changing reading on the LCD display screen. You can't read it well if the screen updates faster than 0.5 seconds.)


The ED88TPlus5G meter samples the signal at a rate of 25000 samples per second, with 12500 samples available for each 0.5second screen update period. 12500 samples are divided into seven bins (+5 to -5dBm, -5 to -15dBm, -15 to -25dBm, -25 to -45dBm, -45 to -55dBm, -60 to -65dBm). It shows the actual real-time signal level distribution within 0.5 seconds and is very useful for analyzing digital RF signals with short burst/pulse ON-time signals and long zero/very low level OFF-time signals.
The 7 sample bins are organized according to the SBM2008 exposure recommendation, and the calculated Peak Value,  Whole Average Value, Peak Average Value, MAX value, and Average Pulse-power value are also shown on the same display window. 

 
(*
The Average Pulse-power value is the average of all signals above the -60dBm threshold level (0.0005mw/m2, "slight concern" based on the SBM2008) ; it is the average ON-time power of all RF burst/pulse for digital burst/pulse type of RF signal).

For example:  in the graph below,  9832 samples are below -60dBm and 50 samples are between -25dBm and -45dBm.
(*The number in the Statistical bins is scaled down by 1.25 to get a total of 10000 for 7 bins, so the user can calculate the percentage of signals in each level bin by dividing the number by 100, or simply ignore the last two digits of the number.) 
 As a result, 0.5 percent of the time the RF pulse/burst signal level is greater than -45dBm (SBM2008 exposure 0.01mw/m2 limit
"high concern") and 98.3 percent of the time it is less than -60dBm (0.0005mw/m2, "slight concern" based on the SBM2008).   This tell you that 98.3% of the time the RF radiation level  is in the  "slight concern"  level (based on the SBM2008 recommendation),  and only 0.5% of time it is in the high concern level.    This is the information the information the EMF experts are looking for.

     


  
   How to access and  use the Statistical data in ED88TPlus5G? 


  Very simple and easy! The ED88TPlus5G provides statistical data for all received signals with a single simple click. When the ED88TPlus5G displays a high reading on the LCD display, a single button click displays the Statistical data of all the signal received in the previous 0.5 seconds. The signal's peak value is also displayed as a Big character, and the distribution of the 12000 sample data is displayed in 7 level bins (based on the SBM2008 recommendation). You can determine whether the signal is of high concern or not by looking at the distribution of the 12000 sampled data in the Statistical data window.