Home |
Search |
Today's Posts |
#5
![]() |
|||
|
|||
![]()
Henry Kolesnik wrote:
"If I wanted to measure the difference between the two fields how would I measure the electric field?" If this is the radiation field, not the reactive field, it would make no difference if you measured the electric field or the magnetic field, as they contain the same quantity of energy. In fact, the energy is identical as one field begets the other field. That`s "The Secret of Propagation". That does not mean the fieldfs can`t be separated. It is easy. Enclose your loop in an effective Faraday screen. This screen prohibits electrostatic coupling to the loop, but freely allows magnetic coupling. Faraday screens are not rare. Nearly every medium wave broadcast station uses a Faraday screen at every tower between the primary and secondary of an air-core coupling transformer. Because, without the screen, capacitive coupling to the tower would favor harmonics of the broadcast frequency over its fundamental frequency and make compliance with FCC rules difficult. The Faraday screen is also an excellent lightning protector. It`s just as easy to allow only capacitive coupling. Simply put a circuit to be kept from magnetic coupling in an enclosure which is completely enclosed in a metal structure (sealed like an expensive signal generator except for one small hole). Use a capacitor through the small hole to couple to the outside world. Only the electric field via the capacitor will influence the circuit in the box. R-F will not penetrate a metal shield, unless it`s special like the sliced-up Faraday screen. Then, it`s only the magnetic field which penetrates. Skin effect requires r-f to flow only on the surface of good conductors to any appreciable depth. Best regards, Richard Harrison, KB5WZI |
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
FCC: Broadband Power Line Systems | Policy | |||
Noise Reducing Antennas | Shortwave | |||
The "TRICK" to TV 'type' Coax Cable [Shielded] SWL Loop Antennas {RHF} | Antenna | |||
The "TRICK" to TV 'type' Coax Cable [Shielded] SWL Loop Antennas {RHF} | Shortwave | |||
Electric and Magnetic fields | Antenna |