Impedance of Loop Antenna
 

Is there a nominal impedance or approximate impedance for a loop antenna?
For example, a dipole is considered 72-ohm, a bevarage 450-ohm. What is a
nominal loops Z?

I have a 4-1/2 foot diameter loop antenna with 12 turns paralled by a
capacitor for the antenna and one additional turn for the pickup coil. The
loop is for the 200 - 500kHz band. About how much is the impedance of such
an antenna? Thanks.

Al

Impedance of Loop Antenna
 

On Mar 10, 12:42 pm, "Al" wrote:
Is there a nominal impedance or approximate impedance for a loop antenna?
For example, a dipole is considered 72-ohm, a bevarage 450-ohm. What is a
nominal loops Z?

I have a 4-1/2 foot diameter loop antenna with 12 turns paralled by a
capacitor for the antenna and one additional turn for the pickup coil. The
loop is for the 200 - 500kHz band. About how much is the impedance of such
an antenna? Thanks.

Al

For short loops (i.e. less than a quarter wave), I'd find the
inductance of the loop then multiply by 2*pi*frequency to get the
antenna impedance. However, I think you are looking for the network
(i.e. LC) impedance. For infinite Q, the parallel resonant circuit
impedance is infinite.
http://en.wikipedia.org/wiki/LC_circuit
The high impedance is generally why the circuit is feed to a high
impedance amplifier or an additional loop is used to inductively
couple to the resonant circuit.