Tables for calculating link budget

To calculate the link budget , simply approximate your link distance , then fill in the following tables :

Free Space Path Loss at 2.4 Ghz

If the received signal is greater than the minimum received signal strength in both directions of the link , as well as any noise received along the path , then the link is possible .

Link planning softwarte


While calculating a link budget by hand is straightforward , there are a number of tools avaiable that will help automate the process . In addition to calculating free space loss . these tools will take many other relevant factors into account as well ( such as tree absorption , terrain effects , climate , and even estimating path loss in urban areas ) . In this section , we will discuss two free tools that are useful for planning wireless links : Green Bay Professional Packet Radio ;s online intereactive network design utilities , and Radio mobile .



Interactive design CGIs

The Green Bay Professional packet Radio group ( GBPRR) has made a variety of very useful link planning tools avaiable for free online . You can browse these tools online at http :
Since the tools are avaiable online , they will work with any device that has a web browser and Internet access .

We will look at the first tool , wireless Network Link Analaysis  , in detail . You can find it online at

To begin , enter the channel to be used on the link . This can be specified in MHz of Ghz . If you dont know the frequency , consult the table in Appendix B . Note that the table lists the channel;s center frequency , while the tool asks for the highest transmitted frequency . The difference in the ultimate result is minmal , so feel free to use the center frequency instead . To find the highest transmitted frequency for a channel , just add 11mHz to the center frequency .

Next , enter the details for the transmitter side of the link , including the tranmission line type , antennna gain , and other details . Try to fill in as much data as you know or can estimate . You can also enter the antenna height and elevation for this site . This data will be used for calculating the antenna tilt angle . For calculating Fresnel zone clearance , you will need to use GBPRR's Fresnel Zone Calculator .

The next section decribes the climate , terrain , and distance of the link . Enter as much data as you know or can estimate . Link distance can be calculated by specifying the latitude and longitude of both sites , or entered by hand .

Now , click the submit buttong for a detailed report about the proposed link . This includes all the data entered , as well as the projected path loss , error rateas and uptime . These numbers are all completely theoretical , but will give yoyu a rough idea of the feasibility of the link . By adjusting values ont he form , you can play "what -if?' to see how changing various parameters will affect the connection .

In addition to the baic link analysis tool , GBPRR provides a "super edition" that wull rpdice a PDF report , as well as a number of other very useful tools 9 including the Fresnel Zone Calculator , Distance & Bearing Calculator , adn Decibel Conversion Calculator to name just a few ) . Source code to most of the tools is provided as well .