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{
"metadata": {
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"worksheets": [
{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h1>Chapter 9: Reflector Antennas<h1>"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"<h3>Example 9-2.1, Page number: 372<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import pi,sqrt\n",
"\n",
"#Variable declaration\n",
"P_transmit = 25000.0 #Power transmitted by station transmitter (W)\n",
"gain_dbi = 29.0 #Gain of array (dBi)\n",
"r = 7500e3 #Distance (m)\n",
"h = 250e3 #Height (m)\n",
"z = 377.0 #Intrinsic impedence of free space (ohm)\n",
"\n",
"#Calculation\n",
"gain = 10**(gain_dbi/10) #Gain of array (unitless)\n",
"erp = gain*P_transmit #Effective radiated power (W)\n",
"p_area = erp/(2*pi*r*h) #power per unit area at distance r (W/m^2)\n",
"field_str = sqrt(p_area*z) #Field strength (mV/m)\n",
"\n",
"#Result\n",
"print \"The effective radiated power is\", round(erp,-5),\"W\"\n",
"print \"The field strength at the distance r is \",round(field_str,3), \"V/m^2\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The effective radiated power is 19900000.0 W\n",
"The field strength at the distance r is 0.025 V/m^2\n"
]
}
],
"prompt_number": 1
}
],
"metadata": {}
}
]
}
|
