

                        FEEDPATT by N1BWT
   
        Paul Wade N1BWT copyright 1997                     
        n1bwt@qsl.net

        Any licensed radio amateur may use this program without 
        charge; all other persons must send $73 to the 
        ARRL Foundation, 225 Main St., Newington, CT 06111
        

        The FEEDPATT program performs the calculations for conventional
        parabolic dish antennas necessary to estimate aperture efficiency 
        with various feed antennas.  Starting with a file of feed pattern
        data, the program plots the feed pattern, then the estimated
        aperture efficiency vs. f/D of the reflector.

        The program only calculates illumination, spillover, and feed
        blockage losses.  In real antennas there are a number of other
        losses, so that the efficiency of a real antenna will be at least
        fifteen percentage points lower than the program calculates.
        
        The input pattern file must have a format like the following
        example (CLAVIN_E.DAT):
......................        
  0       0
  15      0.5
  30      2
  60      7
  90      15
  120     32
  144     36
  150     27
  180     30      //est
  // clavin 74
  // A. Clavin, "A Multimode Antenna Having Equal E- and H-Planes,"
  //IEEE Transactions on Antennas and Propagation, AP-23,
  //Sept. 1975, pp. 735-737.  
  // o.d. = 0.88 wl
  // E-plane

............................

        The first column is the angle in degrees, where zero is the
        center of the feed pattern.  The second column is the amplitude
        in dB below the maximum, with zero being the maximum, usually at
        zero degrees.  An optional third column is the phase of the
        radiation in degrees, relative to zero at the center of the feed
        pattern; the current version of the program ignores this column,
        but a future version may use it.  Data points are required for
        angles from zero to 180 degrees, but no specific number or
        spacing of points is required.  The angles should be
        monotonically increasing.  Comments are preceded by a double
        slash, //, the C++ comment; they may appear at the end of a line
        or on additional lines following the data.
        
        The program asks for pattern data in the two principal planes,
        the E- and H-planes, and approximates a full 3D pattern from
        them.  It would be simple to accomodate additional planes, but
        data is rarely available.  Occasionaly, data is only available in
        one plane; simply enter the same filename for both planes, and
        the resulting pattern will assume perfect symmetry.
        
        The program also asks for the diameter of the reflector and feed
        in wavelengths; since it currently only uses the ratio of the
        two, units don't really matter -- both could be feet or mm.
        
        Output from the program is in encapsulated PostScript (.EPS)
        format, which may be printed on a laser printer or viewed or
        printed on a PC using the GhostScript software
        (http://www.cs.wisc.edu/~ghost/index.html).  Color output
        looks better on the screen, but translates to ugly crosshatching
        on B&W printers.  An example output plot is FIG6.EPS.
        
        To run the program, type FEEDPATT at the DOS prompt, and answer
        the questions.  The filenames may optionally be included on the
        command line:
        
                >FEEDPATT epattern.dat hpattern.dat outfil.eps
                
        On a PC running Windows95 or WindowsNT, I run the program in a
        DOS window and view the output in another window running
        Ghostscript gsview.
        
        ---------------------------------------------------------------
        
        The C++ sources are also included, FEEDPATT.CPP and PS.H; they
        have been compiled using Borland C++ version 4.52 with a DOS
        target.  You can do anything you want with the code, as long as
        you give credit and you don't expect any support.
        
        So, to give credit where due, the pattern integration routine was
        borrowed from DISHFEED.BAS (QEX, Feb. 1996) by Bob Larkin, W7PUA,
        and the cubic spline interpolation routine is from Numerical
        Recipes in Pascal, by Press et. al.
        
        Data files are from the source listed in each file.  Most of them
        I took from graphs in various publications, so inaccuracy is my
        fault.  Also, many publications only show the main part of the
        pattern, so I had to estimate back lobes from similar feeds.
        Errors in sidelobes and backlobes mainly affect the magnitude of
        the efficiency, not the shape of the curve, so the optimum f/D
        for each feed does not change.
        
        ---------------------------------------------------------------

        
        This is a listing of the data files to date with a short
        description of the feed antenna it represents:
        

 COS_3.DAT      idealized cos**n radiator, n = 3

 O_WR90_E.DAT   open WR-90 waveguide at 9.375 GHz (Jasik)
 O_WR90_H.DAT

 CIR_WG_E.DAT    0.97 wl circular waveguide, no choke ring (from Jasik) 
 CIR_WG_H.DAT     

 DIPREF_E.DAT   dipole with rod reflector spaced 0.24 wl - W7PUA EZNEC
 DIPREF_H.DAT
 
 EIA_H.DAT      EIA dual-dipole reference antenna - W7PUA
 EIA_E.DAT

 DHB_A_E.DAT    W7PUA double Handlebar feed - Type A
 DHB_A_H.DAT

 DHB_B_H.DAT    W7PUA double Handlebar feed - Type B
 DHB_B_E.DAT

 CIR_WG_E.DAT   open circular waveguide 0.97 wl in diameter from Jasik
 CIR_WG_H.DAT

 CAN_96_H.DAT   12.5 cm circular waveguide, no ring, at 13 cm - VE4MA
 CAN_96_E.DAT
 
 CAN_77_E.DAT   10 cm circular waveguide, no ring, at 13 cm - VE4MA
 CAN_77_H.DAT


 CLAV54_E.DAT   waveguide with dipole out broad sides, cavity reflector
 CLAV54_H.DAT   Clavin 1954
 
 DIP3WL_E.DAT   dipole over 3 wavelength diameter reflector
 DIP3WL_H.DAT
 
 CLAVIN_H.DAT   Clavin feed 1974 - slot fed cavity with probes 
 CLAVIN_E.DAT
 
 VE4MA_H.DAT    VE4MA feedhorn at 13 cm
 VE4MA_E.DAT    10 cm waveguide with 24cm choke ring

 KUMAR_E.DAT    Kumar feedhorn (original reference for VE4MA)
 KUMAR_H.DAT

 S_IMU_E.DAT    W2IMU dual-mode feedhorn (no H pattern, says it's symmetrical)
 
 L_IMU_E.DAT    large W2IMU, 1.86 wavelength aperture
 L_IMU_E2.DAT   other half of E-plane

 L_CHAP_H.DAT   chaparral style - waveguide diameter = 0.846 wl
 L_CHAP_E.DAT

 S_CHAP_E.DAT   chaparral style - waveguide diameter = 0.744 wl
 S_CHAP_H.DAT

 SLCHAP_E.DAT   slotted chaparral style - waveguide diameter = 0.76 wl
 SLCHAP_H.DAT

 chap10_e.dat   Chaparral "11GHz Superfeed measured at 10.368 GHz
 chap10_h.dat

 chapof_e.dat   Chaparral 11 GHz offset feed  measured at 10.368 GHz
 chapof_h.dat

 penny_e.dat    G4ALN "Penny" feed measured at 10.368 GHz
 penny_h.dat
 
 rehorn_e.dat   small rectangular horn measured at 10.368 GHz
 rehorn_h.dat   E=1.25" H=1.80" Len=1.75" 

 SCALAR_H.DAT   Scalar (corrugated tapered conical horn)
 SCALAR_E.DAT   used at NRAO

 GRNBNK_E.DAT   NRAO Greenbank WV, Dual-band feed at S-band
 GRNBNK_H.DAT
 
 PARKES_E.DAT   Parkes 210 ft. Radiotelescope 1968 - two-hybrid-mode feed
 PARKES_H.DAT

 parkes23.dat   Parkes 210 ft. Radiotelescope at 2.3 GHz - two-hybrid-mode feed

 KOCH_E.DAT     Koch - Multiring Coaxial feed
 KOCH_H.DAT

 SHUKLA_E.DAT   Shukla, "A High Efficiency Horn Antenna Feed," 
 SHUKLA_H.DAT

 HEL_1R8E.DAT   Helical 1.59 turn 30 in Ground plane, 1.8 GHz
 HEL_1R8H.DAT

 HEL_2R4E.DAT   Helical 1.59 turn 30 in Ground plane, 2.4 GHz
 HEL_2R4H.DAT

 H7_29_E.DAT     7 turn helix with 0.29 wl ground plane - FORWARD radiation
 H7_29_H.DAT      
 
 H7_35_E.DAT     7 turn helix with 0.35 wl ground plane - FORWARD radiation 
 H7_35_H.DAT      
 
 H7_6_E.DAT      7 turn helix with 0.6 wl ground plane - FORWARD radiation
 H7_6_H.DAT       

 BH7_10GE.DAT    7 turn helix with 0.29 wl ground plane BACKFIRE at 10 GHz
 BH7_10GH.DAT     

 BH7_11GE.DAT    7 turn helix with 0.29 wl ground plane BACKFIRE at 11 GHz   
 BH7_11GH.DAT     
 
 B_H7_29E.DAT    7 turn helix with 0.29 wl ground plane BACKFIRE radiation
 B_H7_29H.DAT  
   
 B_H7_35E.DAT    7 turn helix with 0.35 wl ground plane BACKFIRE radiation
 B_H7_35H.DAT     
 
 CON_A_E.DAT     conical horn A - 1.85" long, 30 degree flare (Love)
 CON_A_H.DAT      

 CON_B_E.DAT     conical horn B - 2.0" long, 45 degree flare (Love) 
 CON_B_H.DAT      


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