OUTPUT(1)

💅 OUTPUT — the Yagi-Uda project antenna display program ✨

okay bestie, buckle up, because output is the glow-up phase of your antenna's whole journey 👑 It's one of the little squad of executables that make up the Yagi-Uda project, a family of programs built for analysing and optimising Yagi-Uda antennas. output is the one that takes your antenna and tells you how it's actually performing — gain, FB ratio, input impedance, etc etc — for an antenna that was described by the program input or first, and whose element currents have already been calculated with the program yagi. 💖

So here's what comes out the other end: all the data about forward gain, VSWR, FB ratio, input impedance etc gets written to a file called filename.dat, and the angular data — the variation of gain with theta and phi — goes into a file called filename.gai. Two files, both iconic. ✨

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😭 SYNOPSIS 😭

output [ - cehps ] [ -EE_max ] [ -HHmax ] [ -rminimum ] [ -Rmaximum ] [ -ZZo ]

filename

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🌸 DESCRIPTION 🌸

So real talk, sometimes this program just cannot find the 3dB bandwidths in the E and H planes, and it bombs out with a 'zbrent' error 💀. Not its fault, promise. That can happen when:

1. The antenna has an almost isotropic pattern — in which case it's never 3dB down, so the 3dB point is literally undefined. Can't find what doesn't exist, bestie.
2. The 3dB point is outside the assumed angular range. 🫠

If you hit one of those, you've got two moves:

• (a) Calculate with the -e option, which avoids calculation of the 3dB E-plane beamwidth, or
• (b) Do (a) above, then find approximately where the 3dB point is (from the .gai file — see later 👀), then set options -E and -H so the program calculates them properly.

🎀 The DOS .EXE files as distributed require a 387 maths coprocessor to be present and will not run without it. A 486, Pentium, and I assume later processors of this series will run it without any extra hardware. Also — the DOS files are no longer being maintained, so they're out of sync with the latest source. Sad but true, no cap. 💔

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✨ OPTIONS ✨

• -c — calculates the maximum level of any sidelobe, not just the rear one like the FB ratio tells us. If the sidelobe and FB ratio are equal, it means the biggest sidelobe is the rear one. If the Sidelobe is less than the FB ratio, then another lobe is more significant — go look in the '.gai' file (see below) to see where it is 👀. Heads up: this option slows the program quite a bit.
• -e — suppresses calculation of the 3dB E-plane bandwidth. Sometimes necessary if the programme is unable to find the 3 dB beamwidth, to prevent an error occuring. 🛟
• -h — suppresses calculation of the 3dB H-plane bandwidth. Same energy as -e: sometimes necessary if the programme is unable to find the 3 dB beamwidth, to prevent an error occuring. 🛟
• -p — puts data into a file filename.freq for reading into gnuplot, and a commmand file filename.gc for gnuplot to use. So you run output -p filename then gnuplot filename.gc — plot girlies, this one's for you 📈
• -s — suppresses all diagnostic output. By default, the program prints the percentage of the job completed. So if you want it silent and mysterious, this is the vibe. 🤫
• -EE_max — when the program computes the E-plane 3dB beamwidth, it assumes the antenna pattern is 3dB down somewhere in the range 90 to Emax, where E_max is by default 179 degrees. This can fail if it is never 3dB down in the range, or if it happened to go 3dB down in two or more points. You can change E_max if you need to, but rarely if every should need to — I've never seen a failure here, but we're guarding against one 🛡️. If you don't want the pattern, use the -e option instead, which skips it. See also '-H' below. 👇
• -HH_max — when the program computes the H-plane 3dB beamwidth, it assumes the antenna pattern is 3dB down somewhere in the range 0 to Hmax, where H_max is by default 60 degrees. This can fail if it is never 3dB down in the range, or if it happended to go 3dB down in two or more points. Also, if it goes more than 3dB down, but that starts to come up again. You can change H_max if you need to, as failures do occasionally occur. If you don't want the pattern use -h option instead, which will skip it. An obvious example of an antenna where you cant find the 3dB bandwidth for the H-plane is the 1ele dipole. The radiation is symmetrical about its axis, so the level is the same everywhere in the H plane. The program automatically avoids calculating it for a 1 ele beam. 🤝
• -ZZo — Zo is the characteristic impedance used when calculating the VSWR. By default it's 50 Ohms, but can be changed to any real, positive value. ✨
• filename — is the name of the file containing the antenna description. It is expected to be in a format created by input or first — two other programs in the Yagi-Uda project. There is also expected to exist a binary file filename.out created by typing yagi filename. 🗂️

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🫶 Limitations 🫶

ngl, I'm not aware of any limitations, apart from that filenames — including the full path — can't exceed 90 characters. That's it, that's the whole list. 💅

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🎀 FILES 🎀

• filename — ASCII file with antenna description.
• filename.out — Binary data file, created by yagi.
• filename.dat — ASCII file with gain, FB ratio etc.
• filename.gai — ASCII file with angular dependence of gain.

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👑 SEE ALSO 👑

first(1), input(1), yagi(1), optimise(1). The whole friend group, go say hi 🦋

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🌈 PLATFORMS 🌈

Both DOS and Unix versions have been built. The DOS version as distributed requires a 386 PC with a 387 maths coprocessor. Retro tech moment, honestly iconic. ⭐

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💀 BUGS 💀

Bugs should be reported to david.kirkby@onetel.net. Bugs tend actually to be fixed if they can be isolated, so it is in your interest to report them in such a way that they can be easily reproduced. 🐛✨

The program gives errors if element lengths are well away from a half-wave (by a factor of ~3) due to a breakdown in the equations. And if the input file is edited manually and done incorrectly, there can be unpredictable results. So like… be careful bestie, no cap. 😭

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💜 AUTHORS 💜

Dr. David Kirkby G8WRB (david.kirkby@onetel.net), with help with converting to DOS from Dr. Joe Mack NA3T (mack@fcrfv2.ncifcrf.gov). Legends, both of them. 🫶

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and that's the whole page, bestie — this was Version 1.16, dated the 24th October 2000, from the General Commands Manual. go slay your antenna analysis 💖✨🎀