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This page contains a set of equations and free javascript converters and calculators relevant to designing wireless implimentations. All the scripts are released under the GPL. The frequencies involved are, at the moment, set for 2.44 GHz to fit in line with an 802.11b WLAN (Wireless Local Area Network). With the advent of 802.11g this will be changed to allow the frequencies to be changed.

- Free space loss (FSL)
- Range at 2.44 GHz (GigaHertz)
- Wavelength in air
- Wavelength in coaxial cable
- Impedance of coaxial cable
- Velocity factor of coaxial cable

- Free space loss (FSL)
- Range at 2.44 GHz
- Effective radiated power (ERP)
- Fade margin or system operating margin

- Convert dBm and milliWatts (mW)
- Convert diameter and circumference
- Convert inches and mm (millimetres)
- Convert miles and metres
- Convert feet and metres

1 inch = 25.4 mm

**C** = **π****D**

Where:

**C**is the circumference of a circle**D**is diameter of a circle**π**is the constant pi =

1 mile = 1609 metres

1 foot = 0.3048 metres

**FSL** = 36.5 + (20 log_{10}(**D** / 1609)) + (20 log_{10}**f**)

Where:

**FSL**is Free Space Loss in dB**D**is distance between antennas in metres**f**is frequency of signal in Hz

**L** = **c**(1 / **f**)

Where:

**L**is wavelength in metres**c**is the speed of light in air 299552816 metres per second**f**is frequency of signal in Hz

**L** = **v****c**(1 / **f**)

Where:

**L**is wavelength in metres**c**is the speed of light in a vacuum 299792458 metres per second**f**is frequency of signal in Hz**v**is the velocity factor of the coaxial cable

**Z _{o}** = {138 / sq_rt (

Where:

**Z**is the characteristic impedance in Ohms_{o}**E**is the dialectric constant**D**is the inner diameter of the outer conductor in metres**d**is the diameter of the inner conductor in metres

**v** = 1 / sq_rt (**E**)

Where:

**v**is the velocity factor of coaxial cable**E**is the dialectric constant

**t** = 1 / **f**

Where:

**L**is the period of the wave in seconds**f**is frequency of signal in Hz

**D** = 10^{((FSL-104.2) / 20)}1609

Where:

**FSL**is Free Space Loss in dB**D**is distance between antennae in metres**f**is frequency of signal in Hz

milliWatts = 10^{(dBm/10)}

Copyright © 2002. Author: Dave Gough).

Psand Limited, 54 Goodwin Road, Ramsgate, Kent, CT11 0JJ, United Kingdom.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

If you do wish to copy this for use you will need to ensure that you have also got wireless.js and interface.js which are in the same directory as this HTML file