CM Model to calculate the dimensions of a resonant square 4-element quad beam. CM All equations calibrated to NEC antenna modeling software for wire diameters CM from 3.16E-5 to 1E-2 wavelengths within about 0.5% from 3.5 - 250 MHz. CM CM By L. B. Cebik, W4RNL (http://www.cebik.com/quad/q4l.html) CM CM Use 'View->Symbol conversion (SHFT+Y)' on 'Geometry (F3)' window to see CM intermediate/resulting calculations/values CE SY Fr=14.175 ' Enter Desired Frequency in MHz. SY WD=1.62814 ' Enter Wire Diameter in mm/inch/WL. SY Hgh=0 ' Average Quad height above ground mtr (ft) SY Inp=mm ' Enable this line for diameter in mm 'SY Inp=in ' Enable this line for diameter in inch 'SY Inp=299.7925/Fr ' Enable this line for diameter in wavelengths SY D=(WD*Inp*FR)/299.7925 ' Get wire diameter in wavelengths SY L=.4342945*LOG(D*10^5) SY LL=L^2, LM=LL*.0128, LN=LM+1.0413, D1=.4342945*LOG(D) SY AD=-.00018, BD=-.002359259259, CD=-.01090277778, DD=-.01971296296, ED=.1174938889 SY DE=(AD*(D1^4))+(BD*(D1^3))+(CD*(D1^2))+(DD*D1)+ED, DE=DE*8 ' Driver side SY AR=.0002666666667, BR=.004237037037, CR=.02554444444, DR=.07158756614, ER=.2119230159 SY RE=(AR*(D1^4))+(BR*(D1^3))+(CR*(D1^2))+(DR*D1)+ER, RE=RE*8 ' Reflector side SY AI=-.0002, BI=-.002525925926, CI=-.01182777778, DI=-.02473915344, EI=.1008246032 SY IR=(AI*(D1^4))+(BI*(D1^3))+(CI*(D1^2))+(DI*D1)+EI, IR=IR*8 ' Director1 side SY AT=-.0006, BT=-.009059259259, CT=-.04912777778, DT=-.1152343915, ET=.01678174603 SY TT=(AT*(D1^4))+(BT*(D1^3))+(CT*(D1^2))+(DT*D1)+ET, TT=TT*8 ' Director2 side SY SP=.1635 ' Reflector - Driver space SY IP=.481 ' Director1 - Reflector space SY ATT=.0026666666667, BTT=.036888888889, CTT=.177, DTT=.3386587302, ETT=1.046738095 SY TTP=(ATT*(D1^4))+(BTT*(D1^3))+(CTT*(D1^2))+(DTT*D1)+ETT ' Director2 - Reflector space SY Scal=1 ' Use this line if output dimensions in meters. 'SY Scal=ft ' Use this line if output dimensions in feet. SY WL=299.7925/(Scal*Fr) ' Wavelength in Meters/Feet SY Ds=DE/8 * WL ' Driver half side. SY Rs=RE/8 * WL ' Reflector half side. SY Rd=SP * WL ' Reflector-Driver Space. SY I1s=IR/8 * WL ' Director1 half side. SY I1d=(IP-SP) * WL ' Director1-Driver Space. SY I2s=TT/8 * WL ' Director2 half side. SY I2d=(TTP-SP) * WL ' Director2-Driver Space. SY Wr=D/2 * WL ' Wire radius. GW 1 11 0 -Ds HGH-Ds 0 Ds HGH-Ds Wr 'Reflector GW 2 11 0 Ds HGH-Ds 0 Ds HGH+Ds Wr GW 3 11 0 Ds HGH+Ds 0 -Ds HGH+Ds Wr GW 4 11 0 -Ds HGH+Ds 0 -Ds HGH-Ds Wr GW 11 11 -Rd -Rs HGH-Rs -Rd Rs HGH-Rs Wr 'Driver GW 12 11 -Rd Rs HGH-Rs -Rd Rs HGH+Rs Wr GW 13 11 -Rd Rs HGH+Rs -Rd -Rs HGH+Rs Wr GW 14 11 -Rd -Rs HGH+Rs -Rd -Rs HGH-Rs Wr GW 21 11 I1d -I1s HGH-I1s I1d I1s HGH-I1s Wr 'Director 1 GW 22 11 I1d I1s HGH-I1s I1d I1s HGH+I1s Wr GW 23 11 I1d I1s HGH+I1s I1d -I1s HGH+I1s Wr GW 24 11 I1d -I1s HGH+I1s I1d -I1s HGH-I1s Wr GW 31 11 I2d -I2s HGH-I2s I2d I2s HGH-I2s Wr 'Director 2 GW 32 11 I2d I2s HGH-I2s I2d I2s HGH+I2s Wr GW 33 11 I2d I2s HGH+I2s I2d -I2s HGH+I2s Wr GW 34 11 I2d -I2s HGH+I2s I2d -I2s HGH-I2s Wr GS 0 0 Scal GE LD 5 0 0 0 58000000 ' Copper wire EX 0 1 6 0 1 0 'GN 2 0 0 0 13 0.005 ' Use this line if ground used FR 0 1 0 0 Fr 0 'CM Enable below SY lines to see some performance predictions. Use 'CM 'View->Symbol conversion (SHFT+Y)' on 'Geometry (F3)' window to 'CM see intermediate and resulting values ' 'SY AZ=1.2, BZ=13.92592593, CZ=60.777777778, DZ=113.9177249, EZ=132.618254 'SY ZR=(AZ*(D1^4))+(BZ*(D1^3))+(CZ*(D1^2))+(DZ*D1)+EZ ' Approx. feedpoint imp. 'SY AG=-.1, BG=-1.184444444, CG=-5.228333333, DG=-9.831507937, EG=4.045238095 'SY GN=(AG*(D1^4))+(BG*(D1^3))+(CG*(D1^2))+(DG*D1)+EG ' Approx. Free space Gain 'SY AW=.07, BW=1.048518519, CW=6.173055556, DW=17.12092593, EW=21.34722222 'SY SW=(AW*(D1^4))+(BW*(D1^3))+(CW*(D1^2))+(DW*D1)+EW ' Approx. 2:1 SWR bandwidth 'SY AF=-.03, BF=-.27666667, CF=-.4475, DF=2.348809524, EF=7.853214286 'SY FB=(AF*(D1^4))+(BF*(D1^3))+(CF*(D1^2))+(DF*D1)+EF ' Approx. >20dB FB bandwidth EN