Weather Station Hardware => Blitzortung => Topic started by: miraculon on August 05, 2014, 03:58:01 PM

Title: B-Field or H-Field?
Post by: miraculon on August 05, 2014, 03:58:01 PM
Everyone uses the term "H-Field" to describe the magnetic field of the lightning.

I thought H-Field involves permeability. Is the magnetic component of the incoming E-M wave actually "B-Field" and becomes an H-Field once it enters the ferrite antenna? (describing the internal field within the antenna)

Is the incoming field from the lightning actually B-Field, and H-Field exists within the antenna?

Inquiring minds want to know....


Greg H.
Title: Re: B-Field or H-Field?
Post by: JonathanW on August 05, 2014, 04:40:43 PM
I was wondering when someone would say something about this :)

It's been 10 years since I took a "fundamentals of magnetics" class.  I'll have to go to my notes.
Title: Re: B-Field or H-Field?
Post by: Cutty Sark Sailor on August 05, 2014, 04:43:55 PM
Have fun: It's sorta like this: The H field strength used to be measured in oersteds.
H represents the "magnetic field strength". B is the density of the flux lines, M is magnetization of any material inside the H field. B is the induction and H is the field generating the induction. M would be the magnetic force induced in the material. H is measured in amperes per meter, B by number of lines per unit of measurement, and M could be joules or amperes per meter.
M would be what exists within the antenna. So given an H-field of a certain strength crossing an inductive material of a certain density/permeability  would create a B field of so many lines, which would induce an M energy of so many joules or amperes.  More or less.

Work it all backwards for a transmitter.  More or less.
Now .... "Leave Brittany Alone!"....