OUTPUT(5)

📦 version 1.19, in debian bookworm, debian trixie, ubuntu jammy, ubuntu noble, ubuntu questing, ubuntu resolute, ubuntu stonking

💖 NAME 💖

output — the output data file formats, bestie. we're talking about the files the Yagi-Uda project's output program spits out. yes it's a manual page, no it's not boring, come with me 🦋

🌸 DESCRIPTION 🌸

okay so this page is all about the output formats of the files that the Yagi-Uda project's output program creates. and here's the slay part: these files are ASCII files, which literally means you can open them up in any graph plotting program you want. the versatility? unmatched. periodt ✨

🍓 Example of a .dat File

here's a typical .dat file, for a 4ele 144-146MHz beam, optimised for a huge (and useless) FB. yes, "huge (and useless)" is a direct quote, we love a self-aware file format 💀

# 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

let's decode this thing column by column, bestie 🧚

  • The f(MHz) column — the frequency (MHz) at which the data is evaluated. that's the vibe.
  • The E(deg) column — the approximate 3dB E-plane bandwidth, calculated to the nearest 0.1 degree.
  • The H(deg) column — the approximate 3dB H-plane bandwidth, calculated to the nearest 0.1 degree.
  • The (R) column — the input resistance, in Ohms.
  • The (jX) column — the input reactance, in Ohms.
  • The (VSWR) column — the input VSWR, usually referred to a 50 Ohm input, but this may be changed.
  • The Gain (dBi) column — the gain at theta=90 degrees, which is the forward direction of the beam. heads up though: it's possible that a higher gain occurs at other than 90 degrees, but this is not taken into account. and ngl, the antenna is seriously at fault if this occurs 😭
  • The FB(dB) column — the front to back ratio, in dB.
  • The Sidelobes(dB) column — 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

here's a small section of the .gai file, just a lil taste 👑

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

okay this one has TWO sets of angles and the columns are interleaved, stay with me 🫶

  • The f(MHz) column — the frequency, in MHz.
  • The theta column — the angle theta, which the next two columns refer to.
  • The gain-E(dBi) — the gain at theta, relative to an isotropic radiator. this is the E-plane gain. so at the peak (theta), this gives the peak forward gain. iconic.
  • The G(E)-peak — the gain at theta, relative to the peak gain. so at the peak (theta=90 degrees), this is zero.
  • The phi column — ⚠️ has nothing to do with the previous 3 columns, do not be fooled. it's the angle for which the next two columns refer.
  • The gain-H(dBi) — the gain at phi, relative to an isotropic radiator. this is the H-plane gain. so at the peak (phi=0), this gives the peak forward gain.
  • The G(H)-peak — the gain at phi, relative to the peak gain. so at the peak (phi=0 degrees), this is zero.

🦋 Example of a .up File

the .up file lists 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's an example — and the final line is the performance of that 4ele beam from the .dat file we showed 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 — an integer specifying the iteration.
  • The other columns, left to right: gain(dBi), FB, input impedance, VSWR, and the level of the most significant sidelobe, in dB down on the peak gain. easy peasy ✨

👀 SEE ALS0 👀

yagi(1), output(1), input(1), optimise(1), first(1) and yagi(5). go read those too, they're all part of the lore 💜

🎀 AUTHORS 🎀

Dr. David Kirkby G8WRB (david.kirkby@onetel.net), with help with converting to DOS from Dr. Joe Mack NA3T (mack@fcrfv2.ncifcrf.gov). shoutout to the legends 🙌

and that's the whole page, bestie!! this was Version 1.16, dated 24th October 2000 — yeah it's vintage, but vintage is just another word for iconic 💅✨

📦 where this page comes from