CM CHA F-Loop Antenna NEC model by Carol F. Milazzo, KP4MD CM Vertical orientation (using GH command) CM http://www.qsl.net/kp4md/magloop.htm CM Frequency = 14.15 MHz top feed CM Impedance 50 ohms CM 18-side polygon CM LMR-400 loop CM Free space CE SY frq=14.15 'frequency MHz SY c=4.28e-11 'Input resonating capacitance SY rc=2*(5800/(frq*(c*1e12)^2)+0.0039*(frq^0.5)) 'Calculate capacitor Rc SY d=2.44 'Input loop diameter feet SY r=0.5*d 'Calculate loop radius SY od=0.405 'Input loop cable outer dia. inches SY rad2=0.5*od/12 'Calculate loop cable outer radius feet SY dia=0.32 'Input loop conductor dia. inches SY rad=0.5*dia/12 'Calculate loop conductor radius feet SY n=18 'Input n-polygon main loop SY h=5 'Input height to loop feet GH 1 n 1e-300 1e-300 r r r r rad GM 0 0 90 90-180/n 0 0 0 h+r 0 GS 0 0 0.3048 GE 0 LD 0 1 n n rc 0 c LD 5 0 0 0 4500000 LD 7 0 0 0 4.5 rad2 GN -1 EK EX 0 1 n/2 0 1. 0 0 FR 0 0 0 0 frq 0 EN