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I'm trying to find some data concerning current Earth-satellite radio communication systems, namely general characteristics of the equipment currently used on satellites. Specifically, I'm interested in common parameters of satellite transmitters working in Ka and X range such as

  • Tx power
  • Antenna gain
  • EIRP (which is basically Tx+Antenna gain)

Is this information public and if it is, how and where can I find it? Thank you very much in advance!

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    $\begingroup$ That all really depends on what you transmit – a Gb/s video program bouquet link for a geostationary satellite will be fundamentally different from a Command&Control link that pushes a few bits per second to a satellite in LEO; so, this can't be universally answered; you must describe what the link does. Note that this is very close to what we comm engineers call Link Budget calculation. If I were you, I'd google that :) $\endgroup$
    – user17550
    Commented Mar 13, 2017 at 8:57
  • $\begingroup$ For example, you've probably seen TV uplink dishes – which tend to be rather bulky, but that "pays" because they don't have to move, and every dB you get in gain has positive effect on your system performance. On the other hand, Inmarsat's upcoming Global Xpress satellite internet/telephony thing works in Ka band, and is aimed at antennas on commercial airplanes - certainly not 5m dishes; and those two applications are at least comparable in data rate. $\endgroup$
    – user17550
    Commented Mar 13, 2017 at 9:02
  • $\begingroup$ @MarcusMüller, yes, thank you, this is helpful :) I was wondering though whether it's possible to find a table like <sat.name>, <sat. model>, <Tx band>, <Tx power> and so on for several (non-secret, non-military I guess) active satellite including LEO and GEO, observation and communication... For comparing and analysis purposes, since as you said the design may differ drastically. My searches have been fruitless yet. $\endgroup$
    – Glinka
    Commented Mar 13, 2017 at 10:12
  • $\begingroup$ I don't think that table would be overly helpful. You just design that forward. You calculate how much power must reach the satellite, you calculate path loss, you define a receiver operation characteristic (ie. amount of outages you're willing to accept), you derive a security margin from that, this gives you amount of power you need to radiate, and based on your ability to be sure that your satellite is within the beam center, and your amplifier vs antenna cost tradeof, design an antenna/amplifier system.It really doesn't help much to know what others did for their very specific application. $\endgroup$
    – user17550
    Commented Mar 13, 2017 at 10:20
  • $\begingroup$ @MarcusMüller, but that's actually exactly what I need. I need to make an overview that includes that kind of table, methods of calculating link budget, some other stuff. And whilst other stuff are easily googleable, obtaining solid references to the current operating systems has presented a challenge. $\endgroup$
    – Glinka
    Commented Mar 13, 2017 at 10:33

1 Answer 1

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I was wondering though whether it's possible to find a table like sat.name, sat. model, Tx band, Tx power and so on f

I don't think that table would be overly helpful.

You just design that forward. You calculate how much power must reach the satellite, you calculate path loss, you define a receiver operation characteristic (ie. amount of outages you're willing to accept), you derive a security margin from that, this gives you amount of power you need to radiate, and based on your ability to be sure that your satellite is within the beam center, and your amplifier vs antenna cost trade-off, design an antenna/amplifier system.

It really doesn't help much to know what others did for their very specific application. Link budget calculations are pretty down to earth (hrhr, a pun) and deterministic – and so are dish and amplifier datasheets. What'd be interesting would be the models for the path loss variations that the operators assume – but you can't read that from the amplifier power and antenna gain, but would need to look into their link budget calculation.

TL;DR: don't compare your antenna with other people's antenna. It's not about the power density you put out, it's what you do with it, and thus, knowing that a different system uses a certain gain and power is absolutely not helpful for you – a factor of 2 in link requirements could easily be incurred by doing some specific detail differently (e.g. channel coding, which you can't see from the outside), and adding 3dB (=factor of 2) gain to a 40dB dish makes a large difference.

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  • $\begingroup$ +1 for your reserve. Howevrt there might be more to this particular question. We don't know where the OP is in their process of understanding what they need to do and whatever field one is in there is always a time when it becomes reassuring to see how real-world examples differ from the text book. That there might be a good learning opportunity here doesn't mean that there is an answer to the question as it has been asked, perhaps helping to re-target the question could be a good next step. $\endgroup$
    – Puffin
    Commented Mar 13, 2017 at 12:49
  • $\begingroup$ @Puffin, I'm grateful for the answer, the field is new to me and for now I'm fumbling in the dark, so any clarification is extremely useful for me. Extensive summary table of existing equipment is one of the requirements to the overview I'm gonna need to present, and I just don't know where to get this information. $\endgroup$
    – Glinka
    Commented Mar 13, 2017 at 13:21
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    $\begingroup$ @Glinka ok. I am not a link budgets person but I do remember going over link budget examples as a student and finding so many variables that made one situation different to another that it was quite hard going. I wouldn't let that discourage you, rather persevere and see if you can identify your sticking points that could be the basis of a new question. A different approach: look up some of the equipment suppliers, telecoms consultancies, bandwidth resellers etc and give them a call to ask about a typical installation. It sounds like you have a commercial rather than academic need. $\endgroup$
    – Puffin
    Commented Mar 13, 2017 at 13:35
  • $\begingroup$ @Puffin indeed! If you have commercial interest, they might even take the time to set up a call with an application engineer, and maybe they'll even have some kind of link budget spreadsheet ready. $\endgroup$
    – user17550
    Commented Mar 13, 2017 at 14:16

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