{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "

Chapter 25: Sky Wave Propagation

" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "

Example 25-5.1, Page number: 823

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import sqrt\n", "\n", "#Variable declaration\n", "muf = 10e6 #Maximum usable frequency (Hz)\n", "h = 300 #Height of reflection (km)\n", "n = 0.9 #Maximum value of refractive index (unitless)\n", "\n", "#Calculations\n", "Nmax = (1 - n**2)*(muf**2)/81 #Max. Number of electrons per cubic cm\n", "fc = 9*sqrt(Nmax) #Critical frequency (Hz)\n", "dskip = 2*h*sqrt((muf/fc)**2 - 1) #Skip distance (km)\n", "\n", "\n", "#Result\n", "print \"The skip distance is\", round(dskip,1), \"km\"\n", "\n", "#Numerical error in the calculation of sqrt((muf/fc)**2 - 1) " ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "2.34567901235e+11 4358898.94354\n", "The skip distance is 1238.8 km\n" ] } ], "prompt_number": 1 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

Example 25-5.2, Page number: 823

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Variable declaration\n", "fE = 3e6 #Critical frequency for E layer (Hz)\n", "fF1 = 5e6 #Critical frequency for F1 layer (Hz)\n", "fF2 = 9e6 #Critical frequency for F2 layer (Hz)\n", "\n", "#Calculations\n", "N_E = (fE**2)/81 #Concentration of electrons in E layer (per cubic cm)\n", "N_F1 = (fF1**2)/81 #Concentration of electrons in F1 layer (per cubic cm)\n", "N_F2 = (fF2**2)/81 #Concentration of electrons in F2 layer (per cubic cm)\n", "\n", "#Result\n", "print \"The concentration of electrons in E layer is\", round(N_E,-8), \"per cubic cm\"\n", "print \"The concentration of electrons in F1 layer is\", round(N_F1,-8), \"per cubic cm\"\n", "print \"The concentration of electrons in F2 layer is\", N_F2, \"per cubic cm\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The concentration of electrons in E layer is 1.111e+11 per cubic cm\n", "The concentration of electrons in F1 layer is 3.086e+11 per cubic cm\n", "The concentration of electrons in F2 layer is 1e+12 per cubic cm\n" ] } ], "prompt_number": 10 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

Example 25-5.3, Page number: 823

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import sqrt\n", "\n", "#Variable declaration\n", "N_E = 0.8*0.111e12 #Concentration of electrons in E layer (per cubic cm)\n", "N_F1 = 0.8*0.3086e12 #Concentration of electrons in E layer (per cubic cm)\n", "N_F2 = 0.8*1e12 #Concentration of electrons in E layer (per cubic cm)\n", "\n", "#Calculations\n", "fE = 9*sqrt(N_E) #Critical frequency in E layer (Hz)\n", "fF1 = 9*sqrt(N_F1) #Cricital frequency in F1 layer (Hz)\n", "fF2 = 9*sqrt(N_F2) #Critical frequency in F2 layer (Hz)\n", "\n", "#Result\n", "print \"The Critical frequency in E layer is\", round(fE,-4),\"Hz\"\n", "print \"The Critical frequency in F1 layer is\", round(fF1,-4),\"Hz\"\n", "print \"The Critical frequency in F2 layer is\", round(fF2,-3),\"Hz\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The Critical frequency in E layer is 2680000.0 Hz\n", "The Critical frequency in F1 layer is 4470000.0 Hz\n", "The Critical frequency in F2 layer is 8050000.0 Hz\n" ] } ], "prompt_number": 18 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

Example 25-6.1, Page number: 829

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import cos, sqrt, pi\n", "\n", "#Variable declaration\n", "hD = 70 #Height of D layer (km)\n", "hE = 130 #Height of E layer (km)\n", "hF1 = 230 #Height of F1 layer (km)\n", "hF2 = 350 #Height of F2 layer (km)\n", "theta = 10*pi/180 #Angle of incidence (radians)\n", "\n", "#Calculations\n", "temp = sqrt((cos(theta))**-2 - 1)\n", "d1 = 2*hD*temp #Maximum single hop distance for D layer (km)\n", "d2 = 2*hE*temp #Maximum single hop distance for E layer (km)\n", "d3 = 2*hF1*temp #Maximum single hop distance for F1 layer (km)\n", "d4 = 2*hF2*temp #Maximum single hop distance for F2 layer (km)\n", "\n", "#Result\n", "print \"The Maximum single hop distance for D layer is\", round(d1,1), \"km\"\n", "print \"The Maximum single hop distance for E layer is\", round(d2,2), \"km\"\n", "print \"The Maximum single hop distance for F1 layer is\", round(d3,2), \"km\"\n", "print \"The Maximum single hop distance for F2 layer is\", round(d4,1), \"km\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The Maximum single hop distance for D layer is 24.7 km\n", "The Maximum single hop distance for E layer is 45.85 km\n", "The Maximum single hop distance for F1 layer is 81.11 km\n", "The Maximum single hop distance for F2 layer is 123.4 km\n" ] } ], "prompt_number": 19 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

Example 25-9.1, Page number: 832

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import pi, sqrt, cos\n", "\n", "#Variable declaration\n", "d = 200 #Height of layer (km)\n", "beta = 20 #Takeoff angle (degrees)\n", "R = 6370 #Earth's radius (km)\n", "\n", "#Calculations\n", "phi_0 = 90 - beta #Take off angle for flat earth (degrees)\n", "h = (d/2)/(sqrt((cos(phi_0*pi/180)**-2) - 1)) #Skip distance for case (a) (km)\n", "\n", "phi_02 = 90 - beta - 57.2*d/(2*R)\n", " #Take off angle for spherical earth (degrees)\n", "h2 = (d/2)/(sqrt((cos(phi_02*pi/180)**-2) - 1))\n", " #Skip distance for case (b) (km)\n", "\n", "#Result\n", "print \"The skip distance for case (a) is\", round(h,3), \"km\"\n", "print \"The skip distance for case (b) is\", round(h2,2), \"km\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The skip distance for case (a) is 36.397 km\n", "The skip distance for case (b) is 38.18 km\n" ] } ], "prompt_number": 21 } ], "metadata": {} } ] }