10 Cshunt= 120E-12
   20 Lcoil = 47E-6
   30 segments_A = 5
   40 segments_B = 0.5
   50 PRINT
   60 PRINT
   70 PRINT
   80 PRINT
   90 PRINT
  100 PRINT
  110 PRINT
  120 
  130 PRINT
  140 PRINT
  150 PRINT
  160 
  170 PRINT TAB(15);"matching relative to 1/2 wavelength reactance of 282 ohms"
  180 
  190 PRINT
  200 PRINT TAB(15);"Balum 50ohms to 282ohms (5 turns primary : 12 turns secondary)  "
  210 PRINT
  220 PRINT TAB(15);"Loading trap antenna design spec's"
  230 PRINT TAB(15);"1st leg = ";segments_A;"m  "
  240 PRINT TAB(15);"Cshunt = ";Cshunt/1E-12;"pF";" Lcoil = ";Lcoil/1E-6;"uH  "
  250 PRINT TAB(15);"2nd leg = ";segments_B;"m"
  260 PRINT
  270 PRINT TAB(15);"performance spec's"
  280 PRINT
  290 
  300 FOR f=15 TO 30  STEP 1
  310   Xc=1/(2*PI*f*1E6*Cshunt)
  320   Xl = (2*PI*f*1E6*Lcoil)
  330   seg_A_inductance = segments_A*0.3E-6
  340   seg_B_inductance = segments_B*0.3E-6
  350   
  360   Xseg_A = (2*PI*f*1E6*seg_A_inductance)
  370   Xseg_B = (2*PI*f*1E6*seg_B_inductance)
  380   Trap_effect = Xc*(Xl/(Xc+Xl))
  390   L_effect = Trap_effect/(2*PI*f*1E6)
  400   L_antenna =  L_effect + seg_A_inductance + seg_B_inductance
  410   Antenna_length = L_antenna/0.3E-6
  420   resonant_length = Antenna_length
  430   wave_length = resonant_length /  (300/f)
  440   SWR_imped = (wave_length * 564)/282
  450   IF SWR_imped <1 THEN SWR_imped = 1/SWR_imped
  460   REM IF SWR_imped >1 THEN SWR_imped = SWR_imped - 1
  470   PRINT TAB(15);" freq = ";f;"MHz";TAB(33)"Effect Length = ";resonant_length;TAB(63);" wavelength = ";wave_length;TAB(90);" SWR = ";SWR_imped
  480 NEXT
  490 REM *CHDIR C:\Users\helen\Pictures\HFantenna
  500 REM *SCREENSAVE trap_log_wire_HF_20m_10m.bmp 1,1,2000,1100