antenna-theory.com

[Dan]

When designing the concentric circles as found at this page http://www.antenna-theory.com/antennas/wideband/log-periodic.php
It is mentioned that they are of radii r1, r2,... R1, R2.
Im confused as to what this means, am I multiplying each radii by 1, 2, 3.. etc.? Also, is the number of circles a fixed amount?

Thank you for your time

Regards,
Dan

[Schubert]

r1, r2, etc is just a subscript (i.e. the inner radius of the first tooth, the inner radius of the 2nd tooth)

they are geometrically related per the equation on the listed page

r_(n+1)/r_n = k