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Satellite Internet forum › General and other topics › Link Budget Training

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Link Budget Training

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Ex Member Ex Member	Jun 1^st, 2012 at 11:28pm Does anyone aware of a good place to take a course on link budgeting?
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Eric Johnston

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Reply #1 - Jun 2^nd, 2012 at 8:38pm

Try designing a satellite with beams at Ka, Ku and C band, say 1,2,3 deg diameter.
You have one teleport hub antenna with multi frequency feed.

Your customers are:
C band 3 trunk earth stations (two way links).
Ku band 1000 TV receive only sites.
Ka band 1000 two way VSAT internet access customers.
You have total of 100 watts limit of RF power from the satellite amplifiers.

Play with the link budgets, try various antenna sizes, beam sizes, transponder powers, gain settings etc, all the while aiming for about 10 dB C/N overall.

You will soon learn by experience.
Use these links:
Antenna beamwidth and gain calculator
General purpose link budget calculator
TV distribution link budget calculator
VSAT outlink link budget calculator
VSAT return link budget calculator

There is no correct answer. �Just play with all the variables, trying to get something that you think is about right.
Present your design to the marketing/sales and finance people ! Change your design accordingly and so on....

Best regards, Eric

« Last Edit: Jun 2^nd, 2012 at 10:31pm by Eric Johnston »

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Ex Member Ex Member	Reply #2 - Jun 2^nd, 2012 at 9:24pm Eric, thank you for your reply! I was trying to do some link budgets but, i do not feel my knowledge to be very well structured. This is why I'm looking a good training where it is explained from the very beginning. I can probably do the same by myself and using this forum, but again not sure that I have a good basis to start with. Thanks, Anton
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Eric Johnston

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Reply #3 - Jun 2^nd, 2012 at 10:42pm

Don't worry about it being an unstructured problem. You tackle link budgets from all directions simultaneously, trying for some optimisation, normally involving capacity and price.

Earth station: size, watts, carrier bandwidth.
Satellite input: frequency, beam diameter, input G/T, PDFsat, uplink interference.
Transponder gain, bandwidth, carrier to intermod interference �
Downlink antenna gain, downlink power, downlink EIRP
Receive earth stasion, size, G/T, adj satellite interference.

Each parameter has endless scope for discussion, debate, pricing, feasibility etc. The important thing is that you choose what you think might be good and then discuss as necessary.

It is not that difficult to design a system, the difficult bit is getting someone to pay for it !

Be bold, you can try all kinds of ideas !

Best regards, Eric.

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Ex Member Ex Member	Reply #4 - Apr 25^th, 2013 at 11:16am Dear Eric, I am interesting how to play with link budget calculation for inbound and outbond for DVB-S2 you provide the website.Should you share the link budget calculation in excel format? Email : adisornr@thaicom.net. Best Regards, Addy
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Eric Johnston Senior Member ★★★ Offline Posts: 2109	Reply #5 - Apr 25^th, 2013 at 8:01pm Sorry. I don't have it in excel. Try copying the formulas from my link budget pages. Look at the javascript in the page html source text. Transfer to your excel spreadsheet. The calculations are there on your PC, self contained and there is no need to be on-line to the internet to run the calculators. Best regards, Eric.
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Ex Member Ex Member	Reply #6 - Apr 26^th, 2013 at 3:48am Dear Eric, Thank you for your advice. Best regards, Addy
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