What is the correct way to convert dBuA to mA/m for magnetic field strength?

[temujin]

Hi

I´m a little bit confused regarding conversion to dB:

Regulations for a project I´m on say the maximum magnetic field strength allowed is 60 dBuA/m at 10 m. (here I chose 60 myself for simplicity...)

So the question is will this correspond to 1 A /m at 10 m (10log[1000000/1]=60 dB)

or will it correspond with 1 mA / m at 10 m since 20log[1000/1]=60dB.

should I use 20log or 10 log?

regards
t.

 

[dextercioby]

What has dB (probably 'decibell') have to do with magnetic field strength...?

Daniel.

 

[FredGarvin]

It's decibel. I believe you would want to use 20. The 10 is used in power calculations because of the I^2 term in the equations for power, IIRC.

Since this is out of my realm, I would recommend another opinion. I'll do some searching to see if I can find anything concrete.

 

[venuesystem]

60dBuA is equal to 1mA. Mr. Garvin is correct, you would use 20Log, 10Log is used for power (or more correctly the ratio of 2 powers). for every additional 20dB, add a factor of ten. 80dBuA is equal to 10mA, etc.
KC



Electromagnetics, what a concept.