{
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"name": ""
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"worksheets": [
{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h1>Chapter 25: Sky Wave Propagation<h1>"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 25-5.1, Page number: 823<h3>"
]
},
{
"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": [
"<h3>Example 25-5.2, Page number: 823<h3>"
]
},
{
"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": [
"<h3>Example 25-5.3, Page number: 823<h3>"
]
},
{
"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": [
"<h3>Example 25-6.1, Page number: 829<h3>"
]
},
{
"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": [
"<h3>Example 25-9.1, Page number: 832<h3>"
]
},
{
"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": {}
}
]
}