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Satellite Communications/Relation between Antenna sizr & TX Bandwidth Capacity


Greetings for the day,
I want to Know the Relation between Antenna size and TX Bandwidth Capacity.e.g. What is the Max Bandwidth which can be Transmitted from 1.8 Meter Antenna & why ?



Many thanks for your question.  

There is no real relation in principle between the antenna diameter and the bandwidth that can be transmitted. The bandwidth that can be uplinked depends on the link budget , in other words the ability to transmit enough power to overcome the noise on the link. A smaller antenna will make it harder to close the link (i.e. to get an acceptable C/N, carrier to noise ratio), but in theory this can be overcome by putting more power into the antenna.

So, theoretically, you can transmit a very large bandwidth through a small antenna by transmitting a large amount of power into it.

Practically, of course, there are limits. The antenna will have a frequency response, and if the bandwidth you try to transmit is very large then the signal will be degraded by the antenna frequency response. Also, if you try to put a lot of power into the antenna then you may suffer a physical breakdown of the antenna.

I hope this helps.   Please remember to rate this answer.


Mark C J Posen C.Eng. MIET
RPC Telecommunications Ltd.

Satellite Communications

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Mark C J Posen


I am happy to answer questions of a technical and regulatory nature in the area of satellite and radio communications. I am best able to answer questions about systems and technology and less able to respond to questions about specific hardware and equipment setup and installation, but I'm happy to try and address any question put my way. My main areas of expertise are link analysis (link budgets, performance, Eb/No, capacity), interference analysis (C/I, protection ratios, interference avoidance), spectrum management (frequency coordination, inter-system sharing), Radio Regulation (ITU, ITU-R) and satellite technologies and trends.


I have worked as a satellite communications engineer at a professional level since 1983. Since 1990, as Managing Director of RPC Telecommunications Limited, I have operated a private satellite communications consultancy and have provided technical support to many satellite operators and national governments.

IET - Institution of Engineering and Technology, IEEE - Institute of Electrical and Electronic Engineers

B.Sc. Electrical and Electronic Engineering, Bristol University, 1983, M.Sc. Satellite Communications Engineering, Surrey University, 1986

Awards and Honors
C.Eng. - Chartered Engineer registered with the Engineering Council (UK)

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