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About Mark C J Posen
(Top Expert on this page)

Expertise
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.

Experience
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.

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

Education/Credentials
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)

   

You are here:  Experts > Industry > Satellite Communications > Satellite Communications

SubjectDate AskedExpert

Satellite internet in India11/6/2009Mark C J Posen
  Q: I am looking for 2 way mobile land based satellite internet service in india. do you have any info ...
  A: Many thanks for this question. Regarding satellite internet in India, I don't personally get ...
satellite communication10/20/2009Mark C J Posen
  Q: How to calculate sun outage for a place
  A: Many thanks for this question. Unfortunately it's much too complicated to describe the process ...
Roll Off Factor...10/5/2009Mark C J Posen
  Q: Please tell me that what would be the symbol rate which i can configure in my modulator for 6Mhz ...
  A: There is not really a fixed relationship between the roll-off and the spacing factor in the way that ...
Roll Off Factor...10/1/2009Mark C J Posen
  Q: Please tell me that what would be the symbol rate which i can configure in my modulator for 6Mhz ...
  A: Yes, what you have stated is exactly the case. BUT there is an important clarification here. It ...
Roll Off Factor...9/29/2009Mark C J Posen
  Q: Please tell me that what would be the symbol rate which i can configure in my modulator for 6Mhz ...
  A: Really the issue depends on what ISRO mean when they allocate you 6 MHz. Do they allow a guard-band ...
FEC9/28/2009Mark C J Posen
  Q: In our Uplink, we are changing FEC 3/4 to 5/6,I know advantage of FEC,but can you explain me what ...
  A: When you change from rate 3/4 to rate 5/6 FEC you are reducing the amount of coding (i.e. before you ...
Roll Off Factor...9/24/2009Mark C J Posen
  Q: during symbol rate calculation, we consider Bandwidth=1.28*Symbolrate where the roll off factor = ...
  A: I am not familiar with that calculator, but I took a look at the page you indicated. For each of ...
Latitude & Longitude9/19/2009Mark C J Posen
  Q: I want know about Latitude and Longitude,Plz explain my question? sanat
  A: You ask a very general question, so I don't know if you were really looking for something more ...
Roll Off Factor...9/17/2009Mark C J Posen
  Q: during symbol rate calculation, we consider Bandwidth=1.28*Symbolrate where the roll off factor = ...
  A: Sorry it's taken me a while to answer but I've been very busy this week. The 3dB Satellite ...
Roll Off Factor...9/14/2009Mark C J Posen
  Q: during symbol rate calculation, we consider Bandwidth=1.28*Symbolrate where the roll off factor = ...
  A: The roll-off factor of a digital filter defines how much more bandwidth the filter occupies than ...
Antenna9/14/2009Mark C J Posen
  Q: In earth station antenna, there are two categories: a) Cassegrain b) Gregorian I want to know that ...
  A: Cassegrain antennas (where the subreflector is a hyperbola) are generally more popular for ...
FEC9/7/2009Mark C J Posen
  Q: I know why we are using FEC.Plz tell me why we are using 3/4 and 5/6 etc.what the means of 3 and 4 ...
  A: Many thanks for your question and I apologise for the short delay in answering. In any digital ...
carrer options in satellite communications9/6/2009Mark C J Posen
  Q: good evening. i am parnita and im currently doing b.tech degree in electronics and communication,4th ...
  A: Many thanks for your question. The field of satellite communications is a really interesting one ...
C/N9/2/2009Mark C J Posen
  Q: I was trying to calculate downlink C/N for our C band downlink freq.To find downlink C/N i used the ...
  A: Many thanks for your question and I apologise for the short delay in answering. There is a small ...
satellite communication7/8/2009Luis Emiliani
  Q: how to calculate center frequency.How to convert RF range frequency into if range.What I know is for ...
  A: well, you have you have your answer right there: in order to determine the center frequency of your ...
link budgeting-Sat Master7/7/2009Luis Emiliani
  Q: I'm calculating link budget using Sat Master. My satellite operator gave me the leased bandwidth and ...
  A: In satmaster, depending on the version you use, you will find the bandwidth of the carrier, ...
satelite bandwidth7/3/2009Luis Emiliani
  Q: Cpuld you please answer me how to calculate a bandwidth for sat uplink I have tried BW=SR x roll-off ...
  A: the allocated bandwidth at the 3dB point of a carrier should be matching the values in the ...
Purpose of Pure carrier (Transmit CW)7/1/2009Luis Emiliani
  Q: Can you tell me the purpose of this option.Many thanks.
  A: the main purpose of that function is to aid in the fine pointing of the system using a spectrum ...
Output back off per carrier and downlink eirp6/30/2009Luis Emiliani
  Q: I am trying to do a link budget for SCPC VSAT network. In this how I can work out Output Back off ...
  A: there are two elements to this. the downlink EIRP can be calculated when you know the transfer ...
How to calculate PEB6/28/2009Luis Emiliani
  Q: I'm interested to know how to calculate PEB. For example, imagine a 72MHz transponder with x3 ...
  A: Well, if you understand that then you are halfway there. let's take a transponder of 51 dBw and 72 ...
Vsat link budget6/25/2009Luis Emiliani
  Q: Hope you had a nice vacation. I am trying to build a link budget for Ku Band Network of 50 ...
  A: well, it all depends on the type of system you purchase. a typical vsat system has a shared outbound ...
like to know the application of satellite to television digital and analog transmission6/24/2009Luis Emiliani
  Q: good sir, please i will like to know as a beginner about the application and explanation of ...
  A: geostationary satellites are perfectly suitable for broadcasting applications, due to the large ...
Vsat link budget6/22/2009Luis Emiliani
  Q: Hope you had a nice vacation. I am trying to build a link budget for Ku Band Network of 50 ...
  A: in terms of capacity : if you need 256K per site, you can say that the outroute or outbound carrier ...
Vsat link budget6/20/2009Luis Emiliani
  Q: Hope you had a nice vacation. I am trying to build a link budget for Ku Band Network of 50 ...
  A: in essence, the process does not change from 1 to 50 sites. it is still the same equation and the ...
Link budget5/13/2009Mark C J Posen
  Q: I doing a link budget where I have the SFD (dBW/m2) needed to saturate the satellite Transponder. As ...
  A: Many thanks for your question. The formula you quote for SFD is correct; it correctly describes ...
antenna5/10/2009Mark C J Posen
  Q: what is the difference between than mesh and solid antenna, and we can use mesh in Ku band or solid ...
  A: Many thanks for your question. Electrically there is not a great deal of difference between mesh ...
Sidelobe mask and off-axis EIRP5/7/2009Mark C J Posen
  Q: As a follow up to your response to above, usually the side lobe pattern is given as: 31 - 25 log10 ...
  A: Many thanks for your question. Antenna sidelobe gain and off-axis EIRP masks are an attempt to ...
Waveguides4/27/2009Nagy George
  Q: I have a simple question regarding waveguides. Here it goes: Why would you use a circular waveguide ...
  A: I did a bit of search for you www.eriinc.com/pubs/WP22026.pdf ...
Link budget4/14/2009Mark C J Posen
  Q: Definition & explanation required that used in link budget of Satellite communication (VSAT), i am ...
  A: Many thanks for your question. There is a good introduction to Link Budgets on my "Satcom Online" ...
Buying and using Satellite Bandwidth.3/23/2009Mark C J Posen
  Q: I'd like to say in advance how I really appreciate you taking the time to answer my question. I am ...
  A: Many thanks for your question. I'm sorry for the small delay in answering it. Your question is an ...
Affect of eclipse season on geostationary satellites.3/14/2009Mark C J Posen
  Q:
  A: Many thanks for your question and I'm sorry for the delay in answering it. Geostationary satellites ...
satellite internet3/11/2009Mark C J Posen
  Q: I planning to connect to the Internet via VSAT. But I was told that it's not allowed in my ...
  A: Many thanks for this question. Yes indeed, there are satellite phones which (at a price, often ...
Antenna3/11/2009Mark C J Posen
  Q: what is the difference between 31 - 25.log(theta) dBW and 29 - 25.log(theta)? Can you explain ...
  A: Many thanks for your question and I'm sorry for the delay in answering it. The formulas that you ...
Choice of uplink & downlink frequency3/9/2009Mark C J Posen
  Q: Why is the uplink frequency always lesser than the downlink frequency ? although this question has ...
  A: Many thanks for this question and I'm sorry for the delay in answering you. The answers which ...
satellite communication3/8/2009Mark C J Posen
  Q: in radio link design,I'd like to calculate the effeicency between certain satellite and associated ...
  A: Many thanks for your question and I'm sorry for the small delay in answering it. In order to ...
Regarding sun outage3/8/2009Mark C J Posen
  Q: Sir , What do you mean by Sun Outage ? Where it affect highly either in C band or Ku band ? Do you ...
  A: Many thanks for this question and I'm sorry for the delay in answering you. I've changed this to a ...
the disadvantages of satellites3/7/2009Mark C J Posen
  Q: what are the disadvantages of satellites?
  A: Many thanks for this question and I'm sorry for the delay in answering you. Like all communications ...
satellite communications3/6/2009Mark C J Posen
  Q: I am a regular reader of your question and answers blog. I would like to ask you some important ...
  A: Many thanks for your question and I'm sorry for the small delay in answering it. You say that you ...
TWTA in satellite3/3/2009Mark C J Posen
  Q: in space segment we mostly use TWTA rather than SSPA. WHY
  A: Many thanks for your question and I'm sorry for the delay in answering it. Both TWTAs and SSPAs are ...
geostationary orbital satellites2/27/2009Mark C J Posen
  Q: what is the role of goestationary orbital satellites in international organizational communication
  A: Many thanks for your question and I'm sorry for the small delay in answering it. I don't fully ...

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