From 6b4759ca41ae39f4df2f19bc539884baedce6e40 Mon Sep 17 00:00:00 2001
From: pux <pux@pux.dom>
Date: Sat, 19 Dec 2020 20:43:08 +0100
Subject: first version, will calculate lambda/4 dipole leg length for any
 given frequency > 0 Hz, velocity factor can be changed, verbose and quiet
 output

---
 calctenna.py | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100755 calctenna.py

diff --git a/calctenna.py b/calctenna.py
new file mode 100755
index 0000000..23deff8
--- /dev/null
+++ b/calctenna.py
@@ -0,0 +1,78 @@
+#!/usr/bin/env python
+
+# calctenna
+# antenna calculator
+# 2020-12-19
+# Oliver Meckmann
+
+import argparse
+
+def run_argparse():
+    argparser = argparse.ArgumentParser()
+    argparser.add_argument(
+        '-f',
+        '--frequency',
+        metavar='frequency',
+        help='Desired frequency in Hz',
+        nargs='?',
+        default='100e6'
+    )
+    argparser.add_argument(
+        '-V',
+        '--velocity-factor',
+        metavar='velocity_factor',
+        nargs='?',
+        default='0.951'
+    )
+    argparser.add_argument(
+        '-q',
+        '--quiet',
+        help='print only result',
+        action='store_true'
+    )
+    args = argparser.parse_args()
+
+    return args
+
+def calc(args):
+    c = 299792458 # speed of light
+
+    try:
+        f = float(args.frequency)
+    except:
+        print("Sorry, frequency input invalid")
+        exit()
+
+    if f <= 0.0:
+        print("Sorry, frequency must be > 0")
+        exit()
+
+    try:
+        V = float(args.velocity_factor)
+    except:
+        print("Sorry, velocity factor input invalid")
+        exit()
+
+    if V < 0.0 or V > 1.0:
+        print("Sorry, velocity factor can only be between 0.0 and 1.0")
+        exit()
+
+    wavelength = float(c) / f
+    wavelength_2 = wavelength/2
+    wavelength_4 = wavelength/4
+    dipole_leg_length = wavelength/4 * V
+
+    return (wavelength, wavelength_2, wavelength_4, dipole_leg_length)
+
+if __name__ == '__main__':
+    args = run_argparse()
+    (wavelength, wavelength_2, wavelength_4, dipole_leg_length) = calc(args)
+
+    if not args.quiet:
+        print("Desired Frequency: " + str(args.frequency) + " Hz")
+        print("Wavelength: %.3f m" % wavelength)
+        print("Wavelength / 2: %.3f m" % wavelength_2)
+        print("Wavelength / 4: %.3f m" % wavelength_4)
+        print("Velocity factor: " + str(args.velocity_factor))
+        print("-> Dipole leg length (lambda/4): ", end='')
+    print("%.3f m" % dipole_leg_length)
-- 
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