Loop antennas

The best performance will then be at a lower frequency (in general).

How does the frequency change with increasing number of turns? Is there a rule?

R

Too many factors. At the very least, the resonant frequency must drop inversely proportional to the total wire length in the loop. So doubling the turns on the sane size loop must at least halve the resonant frequency.

But this is a limit.

Assuming almost all the flux that passes through one turn also passes through all the others, the inductance will rise almost proportional to the square of the number of turns. The inter winding capacitance and other stray capacitance also rises as the turns rise. These two factors also lower the resonant frequency.

"Roger Dewhurst"

** Multi turn loop antennas (or " frame antennas" ) are commonly used on AM band receivers.

In this case, a loop of convenient size can be made to resonate within the band of interest with a small fixed or variable capacitance in parallel.

Works well for local broadcast reception.

........ Phil

no. the multiturn loop will will receive the same frequency but with a higher impedance (more voltage less current -> same power).

If you wany more signal strength, you need multiple loops, or other strategically placed bits... look up "phase array" and "yagi antenna" for two examples.

Bye. Jasen