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Design >> RF Design >> RF link Budget
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Message started by Mark Stanners on Feb 22^nd, 2017, 3:56am

Title: RF link Budget
Post by Mark Stanners on Feb 22^nd, 2017, 3:56am

Firstly an apology for joining the forum just to sponge information.
I have an assignment as part of my uni course which I am struggling with. It is based on RF design and so I am hoping somebody here could help me out. I have searched the forum but nothing really pops up
I have been tasked with completing a link budget analysis for a rf channel between a satellite and a base station at my university.
My problem is that I have done countless hours of research, but must be looking in all the wrong places. I have calculated, using matlab a SNR at the different heights but to fully analyse a link budget do I need to know the minimum SNR, to find the CNR and budget margin?

Channel frequency- it is transmitting in C band and so I have quite a few MHz for my channel. I have researched spare frequencies but have no idea how I can choose my bandwidth for C band (I was going to use 4-4.2 MHz) are there legal implications or can you just jump on a channel?

Also appropriate antennas- how do you decide what type antenna is appropriate? are there specific ones for C band. I know that antenna length ties in to signal length but satellites and base stations are a bit beyond me.

What I was hoping for any help that you RF fans could provide, if its books, websites or just knowledge that you have it would be greatly appreciated.

Thanks,

Mark

Communication Channel Design Parameters:

The following parameters should be utilised for the communication channel design.

Category of satellite: Microsatellite;
Calculated core bus power: 60 W
Allocated communication subsystem percentage for a communication mission (for uplink and downlink data transmission) (%): 19.
Altitude of satellite (km): 700 to 800;
Elevation angle of the satellite(o): 0 to 180
Earth’s radius (km): 6371;
Speed of light (km/s): 300,000;
Available frequencies for uplink and downlink transmissions (GHz): 4 and 6;
Omnidirectional antennas with gains of 0 dBi are installed; and
Noise floor (dBm): -90.

Title: Re: RF link Budget
Post by Hammad33 on Mar 13^th, 2017, 10:28pm

You can use this book. "Microwave and RF Wireless Systems
by David M. Pozar"