E field total value to find the exposure limit  

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AlbertoM
(@albertom)
Active Member
Joined: 8 years ago
Posts: 15
02/11/2011 12:50 pm  

I need to find the total value of E field (V/m) to make in relation with the exposure limit.
I live in Italy. ( 6 V/m is the limit for the law - cell towers phone ). We are speaking about HF spectran and hight frequency ( 800 Mhz - 2400 Mhz )
I collected many informations from my engineers collegues about the system used by specific instruments that are sensible only to E field and are recognized for this measurements.
I built a simple file excel to calculate the total E field.
I used the value recorded from Spectran in dBm , frequency by frequency (columns) , time by time (lines).
I made three different measurements , in Y , X , Z axis .
I calculate the average into the time of dBm , frequency by frequency ( separatly for X , Y , Z ).
With this medium value of dBm , I calculate the S value ( power density ), frequency by frequency , using the correct dBi ( antenna gain) of Omnilog.
I calculated the E field , frequency by frequency.
My collegues tell me that the system, used from the specific instruments that are sensible only to E field and are recognized for this measurements , is calculate the the square root of the sum of the quadratic value of E. This method is applied for the values frequency by frequency and the values in X ,Y ,Z .
I elevate the E value in quadratic , i make the sum for all frequency steps , I make the square root. This method separately for X recording , Y recording , Z recording.
I made the same calculation with the three results for X recording , Y recording , Z recording. In this way I find the total E field in a specific frequency range during a specific time of recording ( 6 minutes for the law )

I don't know if I'm able to explain the concept , but mathematically is very simple.

I'm asking 2 questions.

1° - Do you confirm that this way to calculation is correct ?
2° - Do you think is difficult to insert automatically into the software the calculation of E total field with this logic ?


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AlbertoM
(@albertom)
Active Member
Joined: 8 years ago
Posts: 15
03/11/2011 3:14 pm  

I try to make the same question in other way.
if is difficult make square root of the sum of the quadratic value for E field we can work with S .
I know that for the S power density is necessary to sum the scalar value ( without square root of the sum of the quadratic value ).

My simple question :
Is possible, by software, obtain automatically the sum of the S power density ( calculate with the specific gain antenna in specific frequency ) in all range of frequency scanned in average for the period of recording ? ( To calculate E field is possible manually from S )


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mm_dev
(@mm_dev)
Member Admin
Joined: 8 years ago
Posts: 287
04/11/2011 12:52 pm  

If I understand you correctly (not sure about that) this feature is already implemented in the limits view of the MCS, you just have to define a custom limit using the Limit Editor in the Extras menu.


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AlbertoM
(@albertom)
Active Member
Joined: 8 years ago
Posts: 15
04/11/2011 5:18 pm  

Thanks for reply , but is not what I want to know.
Next week , monday , I'll write in other way .


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Moderator
(@moderator)
Member Admin
Joined: 9 years ago
Posts: 1048
08/11/2011 3:23 pm  

As soon as you will add marker (the number of marker is unlimited) to the MCS you also get the total power of those marker displayed in the spectrum window.
But you have to use a power or field strength unit like W/m², V/m to activate the sum function.

Snip


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