output: Output data file formats

DESCRIPTION

This manual page describes the output formats of the files created by the Yagi-Uda project's output program. The files are ASCII file, so can be analysed with any graph plotting program.

Example of a .dat File

Below is a typical .dat file, for a 4ele 144-146MHz beam, optimised for a huge (and useless) FB.

# Driven=1 parasitic=3 total-elements=4 design=145.000MHz

# Checked from 144.000MHz to 146.000MHz.
f(MHz) E(deg) H(deg) R       jX   VSWR  Gain(dBi)  FB(dB) SideLobes(dB)

144.000 54.7  71.5  44.47  -2.35  1.136  9.386     21.944     16.650

144.500 54.0  70.1  41.34  -0.75  1.210  9.553     27.244     17.153

145.000 53.2  68.4  37.55   1.61  1.335  9.742    103.055     17.777

145.500 52.3  66.6  33.26   5.00  1.530  9.947     25.734     18.547

146.000 51.3  64.6  28.77   9.63  1.832 10.149     18.919     18.919

What is what in the .dat file

The f(MHz) column is the frequency (MHz) at which the data is evaluated at.

The E(deg) column is the approximate 3dB E-plane bandwidth calculated to the nearest 0.1 degree.

The H(deg) column is the approximate 3dB H-plane bandwidth calculated to the nearest 0.1 degree.

The (R) column is the input resistance in Ohms.

The (jX) column is the input reactance in Ohms.

The (VSWR) column is the input VSWR, usually refered to a 50 Ohm input, but this may be changed.

The Gain (dBi) column is the gain at theta=90 degrees, which is the forward direction of the beam. It is possible that a higher gain occurs at other than 90 degrees, but this is not taken into account. The antenna is seriously at fault if this occurs.

The FB(dB) column is the front to back ratio in dB.

The Sidelobes(dB) column is the minimum level in dB down from the peak gain of any sidelobe. This is not calculated unless the '-c' option is used, and then only on some optimisation techniques.

Example of a .gai File

The following is a small section of the .gai file.

f(MHz)     theta  gain-E(dBi) G(E)-peak   phi   gain-H(dBi) G(H)-peak
144.0000 -90.0000  -12.5584   -21.9444 -180.0000 -12.5584  -21.9444

144.0000 -45.0000   -7.3507   -16.7367 -135.0000  -3.5971  -12.9830

144.0000   0.0000 -999.0000 -1008.3860  -90.0000  -0.9010  -10.2870

144.0000  45.0000    0.1848    -9.2012  -45.0000   4.0261   -5.3599

144.0000  90.0000    9.3860     0.0000    0.0000   9.3860    0.0000

144.0000 135.0000    0.1848    -9.2012   45.0000   4.0261   -5.3599

144.0000 180.0000 -999.0000 -1008.3860   90.0000  -0.9010  -10.2870

144.0000 225.0000   -7.3507   -16.7367  135.0000  -3.5971  -12.9830

144.0000 270.0000  -12.5584   -21.9444  180.0000 -12.5584  -21.9444

What is what in the .gai file

The f(MHz) column is the frequency in MHz.

The theta column is the angle theta, for which the next two columns refer.

The gain-E(dBi) is the gain at theta, relative to an isotropic radiator. This is the E-plane gain. Hence at the peak (theta), this gives the peak forward gain.

The G(E)-peak is the gain at theta, relative to the peak gain. Hence at the peak (theta=90 degrees), this is zero.

The phi column has nothing to do with the previous 3 columns. It is the angle for which the next two columns refer.

The gain-H(dBi) is the gain at phi, relative to an isotropic radiator. This is the H-plane gain. Hence at the peak (phi=0), this gives the peak forward gain.

The G(H)-peak is the gain at phi, relative to the peak gain. Hence at the peak (phi=0 degrees), this is zero.

Example of a .up File

The .up file list the improvements made by optimise to an antenna design. Starting from the original design, the file is appended each time a new better design is found. Here is an example, where the final line is the performance of the 4ele beam with the .dat file shown earlier.

    1 7.57dBi,  16.93dB F/B, Z=(31.77-56.34j) Ohms, VSWR=3.95, SL=16.95 dB

   84 7.58dBi,  16.93dB F/B, Z=(31.78-56.32j) Ohms, VSWR=3.95, SL=16.95 dB

  623 7.58dBi,  16.93dB F/B, Z=(31.78-56.28j) Ohms, VSWR=3.95, SL=16.95 dB

89345 9.74dBi, 103.06dB F/B, Z=(37.55 +1.61j) Ohms, VSWR=1.33, SL=17.78 dB

What is what in the .up file

The first column is an integer specifying the iteration. The other columns, going from left to right are gain(dBi), FB, input impedance, VSWR and level of the most significant sidelobe, in dB down on the peak gain.

SEE ALS0

yagi(1), output(1), input(1), optimise(1), first(1) and yagi(5).

AUTHORS

Dr. David Kirkby G8WRB ([email protected]), with help with converting to DOS from Dr. Joe Mack NA3T ([email protected]).

output (5)