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Old Jul 03, 2015, 10:30 AM
IBCrazy is offline
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Quote:
Originally Posted by pc_pilot View Post
I don't have epoxy, can Gorilla glue (white one) be used to secure the antenna feed points to a base?

Thanks
pc_pilot
Probably not. Gorilla glue doesn't stick well to metal.

-Alex
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Old Jul 03, 2015, 10:37 AM
pc_pilot is online now
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Hello Alex, The one I have sticks to metal. Will it affect the signal?
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Old Jul 11, 2015, 12:16 PM
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What is the most important part of the geometry, is it the spacing of the coils or the diameter of the coil? I CNC'd a coil support and then used a 5/8" dowel to coil the wire but the coil is just a few mm too big to fit in the support. It would be easier to cut a new support than to try to sand the dowel, is this ok?
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Old Jul 15, 2015, 11:42 PM
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Hi Alex. I bought one of your 3 turn goggle mountable helix antennas. I haven't even had a chance to try it yet, and I noticed that the solder connecting the cable to the reflector plate has come undone. Is the cable shielding supposed to be glued to the reflector or soldered? Thanks.
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Old Jul 18, 2015, 09:24 PM
IBCrazy is offline
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Quote:
Originally Posted by Budge View Post
Hi Alex. I bought one of your 3 turn goggle mountable helix antennas. I haven't even had a chance to try it yet, and I noticed that the solder connecting the cable to the reflector plate has come undone. Is the cable shielding supposed to be glued to the reflector or soldered? Thanks.
Email me your address and I will send you a replacement. Every once in a while the acid etching I use doesn't fully etch the galvanized steel backplate. I do not know why this is, though.

-Alex
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Old Jul 24, 2015, 02:46 PM
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Played with 4NEC2 a lot lately. Here are my results. Let the pictures do the talking, I have plenty of them

Simple Helical on infinite ground without impedance transformer, just to set a base line:
Name: helical_infgnd.png
Views: 3
Size: 324.5 KB
Description: Name: helical_infgnd_swr.png
Views: 10
Size: 14.6 KB
Description: Name: helical_infgnd_gain.png
Views: 5
Size: 15.2 KB
Description:

Same Helical on circular ground:
Name: helical_circulargnd.png
Views: 3
Size: 149.7 KB
Description: Name: helical_circulargnd_swr.png
Views: 9
Size: 15.2 KB
Description: Name: helical_circulargnd_gain.png
Views: 7
Size: 14.3 KB
Description:

Same Helical on square ground:
Name: helical_squaregnd.png
Views: 2
Size: 196.2 KB
Description: Name: helical_squaregnd_swr.png
Views: 3
Size: 15.1 KB
Description: Name: helical_squaregnd_gain.png
Views: 2
Size: 14.8 KB
Description:

Helical on infinite ground with parallel wire as impedance transformer:
Name: helical_infgnd_wire.png
Views: 2
Size: 323.6 KB
Description: Name: wire_detailed.png
Views: 6
Size: 80.2 KB
Description: Name: helical_infgnd_wire_swr.png
Views: 6
Size: 15.1 KB
Description: Name: helical_infgnd_wire_gain.png
Views: 1
Size: 15.4 KB
Description:

Same Helical on circular ground:
Name: helical_circulargnd_wire.png
Views: 5
Size: 150.2 KB
Description: Name: helical_circulargnd_wire_swr.png
Views: 7
Size: 15.0 KB
Description: Name: helical_circulargnd_wire_gain.png
Views: 2
Size: 15.3 KB
Description:

Same Helical on square ground:
Name: helical_squaregnd_wire.png
Views: 2
Size: 198.2 KB
Description: Name: helical_squaregnd_wire_swr.png
Views: 2
Size: 15.0 KB
Description: Name: helical_squaregnd_wire_gain.png
Views: 3
Size: 14.4 KB
Description:

Helical on infinite ground with bent microstrip as impedance transformer:
Name: helical_infgnd_microstrip.png
Views: 2
Size: 325.2 KB
Description: Name: microstrip_detailed.png
Views: 4
Size: 268.9 KB
Description: Name: helical_infgnd_microstrip_swr.png
Views: 10
Size: 15.2 KB
Description: Name: helical_infgnd_microstrip_gain.png
Views: 2
Size: 14.4 KB
Description:

Same Helical on circular ground:
Name: helical_circulargnd_microstrip.png
Views: 3
Size: 150.0 KB
Description: Name: helical_circulargnd_microstrip_swr.png
Views: 6
Size: 15.3 KB
Description: Name: helical_circulargnd_microstrip_gain.png
Views: 4
Size: 14.6 KB
Description:

Same Helical on square ground:
Name: helical_squaregnd_microstrip.png
Views: 7
Size: 197.0 KB
Description: Name: helical_squaregnd_microstrip_swr.png
Views: 3
Size: 15.2 KB
Description: Name: helical_squaregnd_microstrip_gain.png
Views: 3
Size: 13.8 KB
Description:

Animation of SWR for different microstrip positions, Helical on infinite ground.
Name: helical_microstrip_animation.gif
Views: 12
Size: 393.0 KB
Description:

Helical on infinite ground with wavetrap as impedance transformer: (something is wrong here)
Name: helical_infgnd_wavetrap.png
Views: 5
Size: 324.8 KB
Description: Name: wavetrap_detailed.png
Views: 6
Size: 248.5 KB
Description: Name: helical_infgnd_wavetrap_swr.png
Views: 4
Size: 15.2 KB
Description: Name: helical_infgnd_wavetrap_gain.png
Views: 3
Size: 15.3 KB
Description:

Same Helical on circular ground: (something is wrong here)
Name: helical_circulargnd_wavetrap.png
Views: 3
Size: 149.3 KB
Description: Name: helical_circulargnd_wavetrap_swr.png
Views: 4
Size: 14.8 KB
Description: Name: helical_circulargnd_wavetrap_gain.png
Views: 1
Size: 14.3 KB
Description:

Same Helical on square ground: (something is wrong here)
Name: helical_squaregnd_wavetrap.png
Views: 4
Size: 196.6 KB
Description: Name: helical_squaregnd_wavetrap_swr.png
Views: 4
Size: 14.8 KB
Description: Name: helical_squaregnd_wavetrap_gain.png
Views: 3
Size: 14.2 KB
Description:

Notes:
- The parallel wire only has minimal effect. I couldn't get the wire closer to the ground without facing 4NEC2 limitations.
- 4NEC2 does not seem to handle the wavetrap accurately. The VSWR was all over the place. Sometimes it was even negative which by definition cannot be true. So unfortunately these results should be ignored.
- The bent microstrip does its job fairly well. Only the optimal impedance at a frequency that is about 10% lower than the design frequency.

Here comes the 4NEC2 model for all these Helicals:

Code:
CM Helical antenna
CM Martin7182
CM 18-jun-2015
CM ===
CM As reflector: either use 'ground plane' section
CM   or use values of 'reflector square' or 'reflector circular',
CM   combined with 'no ground plane' section.
CM ===
CM As impedance transformer: use 'parallel wire', 'wavetrap' or 'microstrip',
CM combined with their matching 'active element'.
CE
'==== general properties ===
SY F=2440			'Design frequency in MHz
SY N=5				'Number of turns
SY WRA=0.5			'Wire Radius active element
SY WRT=0.025			'Wire Radius transformer element
SY WRR=0.1			'Wire Radius reflector
SY SL=299792458			'Speed of light in vacuum in m/s
SY WL=SL/(F*1000)		'Wave length in mm
SY CIRC=1.1			'Circumfence factor
SY R=CIRC*WL/(2*pi)		'Radius helical turn in mm
SY H=1.0			'Height of the helical above reflector in mm
SY PA=13			'Pitch angle of turn in degrees 
SY HDD=pi*R*tan(PA)/180		'Height delta per degree at radius distance
'==== feed ===
SY WRF=0.3			'Wire Radius feed
GW	2000	1	R	0	0	R	0	    H	WRF
'==== active element, no impedance transformer at all ===
SY A8=5				'Angle increment of a turn in degrees
SY XAD1=R*cos(A8)		'X active element delta
SY YAD1=R*sin(A8)		'Y active element delta
SY ZAD1=A8*HDD			'Z active element delta
SY N5=N*360/A8	'		Number of wires to copy
'GW  	4000 	1    	R	0	0   	XAD1	YAD1	ZAD1	WRA
'GM 	1	N5	0	0	A8	0	0	ZAD1	4000
'GM 	0	0	0	0	0	0	0	H	4000
'==== impedance transformer; parallel wire ===
SY A1=5				'Angle increment of a turn in degrees
SY A2=90			'Total angle, must be multiple of A1
SY XTD=R*cos(A1)		'X transformer delta
SY YTD=R*sin(A1)		'Y transformer delta
'GW	3000 	1    	R	0	H   	XTD	YTD	H	WRA
'GM	1	A2/A1-1	0	0	A1	0	0	0	3000
'==== active element, combined with parallel wire ===
SY A3=5				'Angle increment of a turn in degrees
SY XAD2=R*cos(A3)		'X active element delta
SY YAD2=R*sin(A3)		'Y active element delta
SY ZAD2=A3*HDD			'Z active element delta
SY N6=(360-A2)/A3+(N-1)*360/A3	'Number of wires to copy
'GW  	4000 	1    	R	0	0   	XAD2	YAD2	ZAD2	WRA
'GM 	1	N6	0	0	A3	0	0	ZAD2	4000
'GM 	0	0	0	0	A2	0	0	H	4000
'==== impedance transformer; microstrip ===
SY LM=WL/8			'Length of flat microstrip
SY WM=LM/2			'Width 
SY LMH=cos(PA)*LM		'Middle length in horizontal plane once mounted
SY NPWM=10			'Number of patches along width (max 20, need to
				' comment/uncomment below GW rules)
SY X=int(NPWM/2)		'Outer radius position [0 .. NPWM]
SY NPLM=NPWM*LM/WM		'Number of patches along length
SY WX=WM*(2X-NPWM)/NPWM		'[-WM .. WM] depending on X
SY Ri=R-WM+X*WM/NPWM		'Inner radius 
SY Ro=Ri+WM			'Outer radius 
SY Rm=(Ri+Ro)/2			'Middle radius 
SY ADM=360*LMH/(NPLM*2*pi*Rm)	'Angle delta neighbouring patches in h plane
SY ADM0=360*LMH/(NPLM*2*pi*R)	'Angle delta0 neighbouring patches in h plane
SY SAM0=(90-NPLM*ADM0)/2	'Start angle0 of microstrip relative to feed 
SY SAM=(SAM0*2R+45WX)/(2R+WX)	'Start angle of microstrip relative to feed 
SY HDADM=HDD*ADM		'Height delta ADM
SY SHM=H+SAM*HDD		'Start height
SY R0=Ri+0WM/NPWM		'Radius #0
SY X0D=R0*cos(ADM)		'X delta #0
SY Y0D=R0*sin(ADM)		'Y delta #0
SY R1=Ri+1WM/NPWM		'Radius #1
SY X1D=R1*cos(ADM)		'X delta #1
SY Y1D=R1*sin(ADM)		'Y delta #1
SY R2=Ri+2WM/NPWM		'Radius #2
SY X2D=R2*cos(ADM)		'X delta #2
SY Y2D=R2*sin(ADM)		'Y delta #2
SY R3=Ri+3WM/NPWM		'Radius #3
SY X3D=R3*cos(ADM)		'X delta #3
SY Y3D=R3*sin(ADM)		'Y delta #3
SY R4=Ri+4WM/NPWM		'Radius #4
SY X4D=R4*cos(ADM)		'X delta #4
SY Y4D=R4*sin(ADM)		'Y delta #4
SY R5=Ri+5WM/NPWM		'Radius #5
SY X5D=R5*cos(ADM)		'X delta #5
SY Y5D=R5*sin(ADM)		'Y delta #5
SY R6=Ri+6WM/NPWM		'Radius #6
SY X6D=R6*cos(ADM)		'X delta #6
SY Y6D=R6*sin(ADM)		'Y delta #6
SY R7=Ri+7WM/NPWM		'Radius #7
SY X7D=R7*cos(ADM)		'X delta #7
SY Y7D=R7*sin(ADM)		'Y delta #7
SY R8=Ri+8WM/NPWM		'Radius #8
SY X8D=R8*cos(ADM)		'X delta #8
SY Y8D=R8*sin(ADM)		'Y delta #8
SY R9=Ri+9WM/NPWM		'Radius #9
SY X9D=R9*cos(ADM)		'X delta #9
SY Y9D=R9*sin(ADM)		'Y delta #9
SY R10=Ri+10WM/NPWM		'Radius #10
SY X10D=R10*cos(ADM)		'X delta #10
SY Y10D=R10*sin(ADM)		'Y delta #10
SY R11=Ri+11WM/NPWM		'Radius #11
SY X11D=R11*cos(ADM)		'X delta #11
SY Y11D=R11*sin(ADM)		'Y delta #11
SY R12=Ri+12WM/NPWM		'Radius #12
SY X12D=R12*cos(ADM)		'X delta #12
SY Y12D=R12*sin(ADM)		'Y delta #12
SY R13=Ri+13WM/NPWM		'Radius #13
SY X13D=R13*cos(ADM)		'X delta #13
SY Y13D=R13*sin(ADM)		'Y delta #13
SY R14=Ri+14WM/NPWM		'Radius #14
SY X14D=R14*cos(ADM)		'X delta #14
SY Y14D=R14*sin(ADM)		'Y delta #14
SY R15=Ri+15WM/NPWM		'Radius #15
SY X15D=R15*cos(ADM)		'X delta #15
SY Y15D=R15*sin(ADM)		'Y delta #15
SY R16=Ri+16WM/NPWM		'Radius #16
SY X16D=R16*cos(ADM)		'X delta #16
SY Y16D=R16*sin(ADM)		'Y delta #16
SY R17=Ri+17WM/NPWM		'Radius #17
SY X17D=R17*cos(ADM)		'X delta #17
SY Y17D=R17*sin(ADM)		'Y delta #17
SY R18=Ri+18WM/NPWM		'Radius #18
SY X18D=R18*cos(ADM)		'X delta #18
SY Y18D=R18*sin(ADM)		'Y delta #18
SY R19=Ri+19WM/NPWM		'Radius #19
SY X19D=R19*cos(ADM)		'X delta #19
SY Y19D=R19*sin(ADM)		'Y delta #19
SY R20=Ri+20WM/NPWM		'Radius #20
SY X20D=R20*cos(ADM)		'X delta #20
SY Y20D=R20*sin(ADM)		'Y delta #20
GW	5000	1	R0	0	0	X0D	Y0D	HDADM	WRT
GW	5001	1	R1	0	0	X1D	Y1D	HDADM	WRT
GW	5002	1	R2	0	0	X2D	Y2D	HDADM	WRT
GW	5003	1	R3	0	0	X3D	Y3D	HDADM	WRT
GW	5004	1	R4	0	0	X4D	Y4D	HDADM	WRT
GW	5005	1	R5	0	0	X5D	Y5D	HDADM	WRT
GW	5006	1	R6	0	0	X6D	Y6D	HDADM	WRT
GW	5007	1	R7	0	0	X7D	Y7D	HDADM	WRT
GW	5008	1	R8	0	0	X8D	Y8D	HDADM	WRT
GW	5009	1	R9	0	0	X9D	Y9D	HDADM	WRT
GW	5010	1	R10	0	0	X10D	Y10D	HDADM	WRT
'GW	5011	1	R11	0	0	X11D	Y11D	HDADM	WRT
'GW	5012	1	R12	0	0	X12D	Y12D	HDADM	WRT
'GW	5013	1	R13	0	0	X13D	Y13D	HDADM	WRT
'GW	5014	1	R14	0	0	X14D	Y14D	HDADM	WRT
'GW	5015	1	R15	0	0	X15D	Y15D	HDADM	WRT
'GW	5016	1	R16	0	0	X16D	Y16D	HDADM	WRT
'GW	5017	1	R17	0	0	X17D	Y17D	HDADM	WRT
'GW	5018	1	R18	0	0	X18D	Y18D	HDADM	WRT
'GW	5019	1	R19	0	0	X19D	Y19D	HDADM	WRT
'GW	5020	1	R20	0	0	X20D	Y20D	HDADM	WRT
GW	5021	1	X0D	Y0D	HDADM	X1D	Y1D	HDADM	WRT
GW	5022	1	X1D	Y1D	HDADM	X2D	Y2D	HDADM	WRT
GW	5023	1	X2D	Y2D	HDADM	X3D	Y3D	HDADM	WRT
GW	5024	1	X3D	Y3D	HDADM	X4D	Y4D	HDADM	WRT
GW	5025	1	X4D	Y4D	HDADM	X5D	Y5D	HDADM	WRT
GW	5026	1	X5D	Y5D	HDADM	X6D	Y6D	HDADM	WRT
GW	5027	1	X6D	Y6D	HDADM	X7D	Y7D	HDADM	WRT
GW	5028	1	X7D	Y7D	HDADM	X8D	Y8D	HDADM	WRT
GW	5029	1	X8D	Y8D	HDADM	X9D	Y9D	HDADM	WRT
GW	5030	1	X9D	Y9D	HDADM	X10D	Y10D	HDADM	WRT
'GW	5031	1	X10D	Y10D	HDADM	X11D	Y11D	HDADM	WRT
'GW	5032	1	X11D	Y11D	HDADM	X12D	Y12D	HDADM	WRT
'GW	5033	1	X12D	Y12D	HDADM	X13D	Y13D	HDADM	WRT
'GW	5034	1	X13D	Y13D	HDADM	X14D	Y14D	HDADM	WRT
'GW	5035	1	X14D	Y14D	HDADM	X15D	Y15D	HDADM	WRT
'GW	5036	1	X15D	Y15D	HDADM	X16D	Y16D	HDADM	WRT
'GW	5037	1	X16D	Y16D	HDADM	X17D	Y17D	HDADM	WRT
'GW	5038	1	X17D	Y17D	HDADM	X18D	Y18D	HDADM	WRT
'GW	5039	1	X18D	Y18D	HDADM	X19D	Y19D	HDADM	WRT
'GW	5040	1	X19D	Y19D	HDADM	X20D	Y20D	HDADM	WRT
GM	1	NPLM-1	0	0	ADM	0	0	HDADM	5000
GW	6000	1	R0	0	0	R1	0	0	WRT
GW	6001	1	R1	0	0	R2	0	0	WRT
GW	6002	1	R2	0	0	R3	0	0	WRT
GW	6003	1	R3	0	0	R4	0	0	WRT
GW	6004	1	R4	0	0	R5	0	0	WRT
GW	6005	1	R5	0	0	R6	0	0	WRT
GW	6006	1	R6	0	0	R7	0	0	WRT
GW	6007	1	R7	0	0	R8	0	0	WRT
GW	6008	1	R8	0	0	R9	0	0	WRT
GW	6009	1	R9	0	0	R10	0	0	WRT
'GW	6010	1	R10	0	0	R11	0	0	WRT
'GW	6011	1	R11	0	0	R12	0	0	WRT
'GW	6012	1	R12	0	0	R13	0	0	WRT
'GW	6013	1	R13	0	0	R14	0	0	WRT
'GW	6014	1	R14	0	0	R15	0	0	WRT
'GW	6015	1	R15	0	0	R16	0	0	WRT
'GW	6016	1	R16	0	0	R17	0	0	WRT
'GW	6017	1	R17	0	0	R18	0	0	WRT
'GW	6018	1	R18	0	0	R19	0	0	WRT
'GW	6019	1	R19	0	0	R20	0	0	WRT
GM 	0	0	0	0	SAM	0	0	SHM	5000
'==== impedance transformer; wavetrap ===
SY LW=WL/8			'Length of flat wavetrap
SY WW=LW/2			'Width 
SY LWH=cos(PA)*LW		'Length in horizontal plane once mounted
SY NPWW=10			'Number of patches along width
SY NPLW=NPWW*LW/WW		'Number of patches along length 
SY XWD=NPWW*WW/(2*NPWW*sqr(2))	'X delta
SY YWD=NPWW*WW/(2*NPWW*sqr(2))	'Y delta
SY HDE=sqr(R*R-(LWH/2)*(LWH/2))	'H distance to edge of wavetrap from origin
SY SAW=atn((2/LWH)*HDE)-45	'Angle in horizontal plane; no acos in 4NEC2
SY XW=R*cos(SAW)-XWD		'X position
SY YW=R*sin(SAW)-YWD		'Y position
SY ZW=H+SAW*HDD			'Z position
'GW	7000	1	0	0	0	WW/NPWW	0	0	WRT
'GM	1	NPWW-1	0	0	0	WW/NPWW	0	0	7000
'GW	7100	1	0	0	0	0	LW/NPLW	0	WRT
'GM	1	NPWW	0	0	0	WW/NPWW	0	0	7100
'GM	1	NPLW-1	0	0	0	0	LW/NPLW	0	7000
'GW	7300	1	0	LW	0	WW/NPWW	LW	0	WRT
'GM	1	NPWW-1	0	0	0	WW/NPWW	0	0	7300
'GM	0	0	PA	0	45	XW	YW	ZW	7000
'==== active element, combined with wavetrap / microstrip ===
'==== choose SAT=SAW for wavetrap, SAT=SAM for microstrip ===
'SY SAT=SAW			'Start angle transformer in horizontal plane
SY SAT=SAM			'Start angle transformer in horizontal plane
SY ALT=90-2*SAT			'Angle along circle through transformer 
SY HT=ALT*HDD			'Height transformer
SY A4=10			'Angle increment of a turn in degrees
SY N2=3				'Number of wires leading/trailing to wavetrap 
SY A5=SAT/N2			'Angle of leading/trailing wires
SY A6=0.7*A5			'Angle of last-1 leading/trailing wire
SY XL1=R*cos(A5)		'X leader 1
SY YL1=R*sin(A5)		'Y leader 1
SY ZL1=A5*HDD			'Z leader 1
SY XL2=R*cos((N2-1)*A5)		'X leader 2 
SY YL2=R*sin((N2-1)*A5)		'Y leader 2 
SY ZL2=(N2-1)*A5*HDD		'Z leader 2 
SY XL3=R*cos((N2-1)*A5+A6)	'X leader 3 
SY YL3=R*sin((N2-1)*A5+A6)	'Y leader 3 
SY ZL3=((N2-1)*A5+A6)*HDD	'Z leader 3 
SY XL4=R*cos((N2-1)*A5+A5)	'X leader 4 
SY YL4=R*sin((N2-1)*A5+A5)	'Y leader 4 
SY ZL4=((N2-1)*A5+A5)*HDD	'Z leader 4 
SY ZT=HT+2*ZL4			'Z trailer (mirrored leader)
SY XA1=R*cos(90+A4)		'X end first wire segment starting at 90 deg
SY YA1=R*sin(90+A4)		'Y end first wire segment starting at 90 deg
SY ZA1=(90+A4)*HDD		'Z end first wire segment starting at 90 deg
SY N3=270/A4+(N-1)*360/A4	'Number of wires starting at 90 degrees
GW  	4000  	1	R	0	0	XL1	YL1	ZL1	WRA
GM 	1	N2-2	0	0	A5	0	0	A5*HDD	4000
GW  	4010  	1	XL2	YL2	ZL2	XL3	YL3	ZL3	WRA/2
GW  	4011  	1	XL3	YL3	ZL3	XL4	YL4	ZL4	WRT*2
GM	1	1	0	180	270	0	0	ZT	4000
GW  	4100  	1	0	R	90*HDD	XA1	YA1	ZA1	WRA
GM	1	N3	0	0	10	0	0	A4*HDD	4100
GM	0	0	0	0	0	0	0	H	4000
'==== reflector square ===
SY WG=WL			'Width, approximately
SY LG=WG			'Length, approximately
SY HLG=LG/2			'Half length
SY NPWL=40			'Number of patches per wave length 
SY NPLG=int(NPWL*HLG/WL+0.5)	'Number of patches along length from center
SY GS=HLG/NPLG			'Grid size
SY HWG=WG/2			'Half width
SY NPWG=int(HWG/GS+0.5) 	'Number of patches along width from center
SY XOFF=GS*(R/GS-int(R/GS+0.5))	'X offset to match with feed
SY XLG=-NPWG*GS+XOFF		'Left edge
SY YBG=-NPLG*GS			'Bottom edge
SY YTG=NPLG*GS			'Top edge
'GW	1000	1	XLG	YBG	0	XLG	YBG+GS	0	WRR
'GM	1	2NPWG	0	0	0	GS	0	0	1000
'GW	1100	1	XLG	YBG	0	XLG+GS	YBG	0	WRR
'GM	1	2NPWG-1	0	0	0	GS	0	0	1100
'GM	1	2NPLG-1	0	0	0	0	GS	0	1000
'GW	1300	1	XLG	YTG	0	XLG+GS	YTG	0	WRR
'GM	1	2NPWG-1	0	0	0	GS	0	0	1300
'==== reflector circular ===
SY W=6*R			'Width
SY HW=W/2			'Half width
SY ADR=10			'Angle delta neigbouring segments
SY XR=HW*cos(ADR)		'X delta pie segment of length R
SY YR=HW*sin(ADR)		'Y delta pie segment of length R 
SY N4=360/ADR-1			'Number of pie segments to copy
'GW	1000	21	0	0	0	HW	0	0	WRR
'GW	1001	1	HW	0	0	XR	YR	0	WRR
'GW	1002	1	20HW/21	0	0	20XR/21	20YR/21	0	WRR
'GW	1003	1	19HW/21	0	0	19XR/21	19YR/21	0	WRR
'GW	1004	1	18HW/21	0	0	18XR/21	18YR/21	0	WRR
'GW	1005	1	17HW/21	0	0	17XR/21	17YR/21	0	WRR
'GW	1006	1	16HW/21	0	0	16XR/21	16YR/21	0	WRR
'GW	1007	1	15HW/21	0	0	15XR/21	15YR/21	0	WRR
'GW	1008	1	14HW/21	0	0	14XR/21	14YR/21	0	WRR
'GW	1009	1	13HW/21	0	0	13XR/21	13YR/21	0	WRR
'GW	1010	1	12HW/21	0	0	12XR/21	12YR/21	0	WRR
'GW	1011	1	11HW/21	0	0	11XR/21	11YR/21	0	WRR
'GW	1012	1	10HW/21	0	0	10XR/21	10YR/21	0	WRR
'GW	1013	1	9HW/21	0	0	9XR/21	9YR/21	0	WRR
'GW	1014	1	8HW/21	0	0	8XR/21	8YR/21	0	WRR
'GW	1015	1	7HW/21	0	0	7XR/21	7YR/21	0	WRR
'GW	1016	1	6HW/21	0	0	6XR/21	6YR/21	0	WRR
'GW	1017	1	5HW/21	0	0	5XR/21	5YR/21	0	WRR
'GW	1018	1	4HW/21	0	0	4XR/21	4YR/21	0	WRR
'GW	1019	1	3HW/21	0	0	3XR/21	3YR/21	0	WRR
'GW	1020	1	2HW/21	0	0	2XR/21	2YR/21	0	WRR
'GM	1	N4	0	0	ADR	0	0	0	1000
'=== scaling ===
GS	0	0	0.001	'All sizes are in mm
'==== no ground plane ====
'GE 0				'No ground
'GN -1				'Free space
'==== ground plane ====
GE 1 				'Ground plane
GN 1				'Perfectly conducting ground
'====================================
EK
EX 0 2000 1 0 1 0 0
FR 0 1 0 0 F 0.000
EN
By default it uses design frequency 2.4GHz, 5 turns, infinite ground, bent microstrip as impedance transformer. But all parameters can be changed easily. If you need help, you know where to find me

Martin
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Old Jul 26, 2015, 10:29 PM
IBCrazy is offline
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Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
11,054 Posts
WOW! That is a lot of code. My version of 4NEC2 won't even allow me to use that much. I need to figure out how to increase the number of symbols so it will make this. I keep using MSExcel and importing the whole spreadsheet.

-Alex
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Old Yesterday, 04:20 AM
Martin7182 is offline
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Wallop!
Martin7182's Avatar
Bussum, Netherlands
Joined Oct 2009
915 Posts
Settings -> Memory usage -> Max-nr of SYmbols

I've set this to 300 and it works fine. Too bad the software doesn't allocate them automatically according to your needs. In fact all those "Max-nr..." memory usage settings are a sign of bad technical software design; if the number is set too low, it won't work and if it's too high then you'll use excessive memory.

I like the expressive power of 4NEC2 although you need a lot of symbols for that. What I still miss are trigonometric functions like "acos" and "asin". Luckily it has "atn" but using that in combination with "sqr" is quite cumbersome. What I also miss are "Variable Move" rules for variables, analogue to "GM" rules for segments. Note the difference between the wavetrap model and my bent microstrip. The former is rectangular which only needs a fixed number of variables (to get an arbitrary fine grid) whereas the latter uses different wire lengths, all to be specified by hand.

Martin
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