This is the 4NEC2 antenna bend model for: Dipole Sag
To use this model:
Below. Highlight and copy (Ctrl C) the program control codes (CM,
CE, SY,etc).
Open Windows Wordpad and copy (Ctrl V) the control codes into Wordpad.
Go to "File, Save as..." and name your new antenna model.
In Windows Explorer, right-click on your new model and "Rename" the file to end as ".nec".
Open your new model to optimize the Length (L=) of the dipole
wire at the Sag Ratio )R=) of interest.
4NEC2 is an NEC2, NEC4, Windows based antenna modeler and optimizer by
Arie Voors.
It is available free of charge at: www.qsl.net/4nec2/
CM Catenary dipole
CM Standardized 1-feed model using #14 AWG
CM Before droop, 1/2 wave feed height over ground at 28.4 mc. with 7.32
dBi gain
CM Set sag ratio (0.1, 0.2, etc) and optimize wire length
CM Calculates droop width and 10 points for plotting
CM Uses point-to-point approximation based on average ratios
CM KK4OBI, Dick Reid, Oct. 2015
CM
CE
SY hgh=5.2817 '150/28.4=5.2817m =1/2 wl
SY L=5.215794 'Compare with optimized length of 1/2 wave
wire dipole =5.1485 meters
SY R= 0.31 'R = Ratio of
sag based on resonant length L :: R=0.001 for dipole L
SY G=L*R 'G=depth of Sag
(droop) at feedpoint - meters
SY DS=((L^2-4*G^2)/(4*G))*Log((L+2*G)/(L-2*G)) 'Droop
Span calculation from G and L
SY S=DS/10 'Size of each of 10 Droop
Segment
SY D1=hgh-G
'Droop at bottom at center feedpoint
SY D2=hgh-0.957*G 'Droop next to bottom
SY D3=hgh-0.848*G 'Droop 2nd from bottom
SY D4=hgh-0.662*G 'Droop at 2/3rds
SY D5=hgh-0.386*G 'Droop next to top
SY D6=hgh
'Top of Droop at ends
GW 1 5
0 0 D1
-s*1 0 D2
#14 'Bottom of left side at feedpoint
GW 2 5
-s*1 0 D2
-s*2 0 D3
#14 'Going up
GW 3 5
-s*2 0 D3
-s*3 0 D4 #14
GW 4 5
-s*3 0 D4
-s*4 0 D5 #14
GW 5 5
-s*4 0 D5
-s*5 0 D6
#14 'Top of left side
GW 6 5
0 0
D1 s*1 0
D2 #14 'Bottom of right side at
feedpoint
GW 7 5
s*1 0 D2
s*2 0 D3
#14 'Going up
GW 8 5
s*2 0 D3
s*3 0 D4 #14
GW 9 5
s*3 0 D4
s*4 0 D5 #14
GW 10 5
s*4 0 D5
s*5 0 D6
#14 'Top of right side
GE -1
GN 2 0
0 0 14 6.e-3
EK
EX 0 6
1 0 1
0 0 'next to center at right side
FR 0 0
0 0 28.4 0
EN Back