All about satellite commnication

Good start!

I'm doing a project on a prototype nanosatellite at the moment 😀 At present, the communications is very limited.. a 4 km 2.4 GHZ radio link, since we are only testing it in the air. If we have a bigger budget, we could at least get a 60 km MHX series radio modem.

A more appropriate choice would be some sort of TNC using the x.25 protocol on amateur radio bands. Better antennas can be fabircated for longer range. But not much data can be transmitted 😔

What would be interesting is, if we can use optical communications for satellite communications! Kind of like deep space comm, but taking account atmospheric distortions.

:Some basics on satellite tv broadcasting:

Here it goes...Many of us may be having dish antennas to recieve channels aired directly from satellites. The complete set consists of a parabolic antenna, LNB(low noise block) and set top box. From the set top box it is connected to tv.😀

And regarding the broadcasted channels - there are FTA(free-to-air) and premium channels.Any one having the right dish, lnb and dish correctly pointed at the right satellite will recieve FTA channels (you want a set top box ofcorse). They are all freely aired that yo dont want to pay for it.😁 But the case is different with premium channels.😔 These would be encrypted by the companies and only if you pay, the channels would be descrambled by them allowing you to watch..! To get more inforation on different fta and premim channels broadcasted on different satellites you may refer to <a href="https://www.lyngsat.com" target="_blank" rel="nofollow noopener noreferrer">LyngSat</a>

All of these channels are mostly broadcasted in either Ku band or C band. There are also S band and extendedC band which are not much in use. Some companies have started broadcasting in Ka band. These bands are differentiated according to their frequencies.
The downlink freqency increases in the order: S band<Extended C band(lower)<C band<Extended C band(upper)<Ku band<Ka band
You will need different sized dishes to recieve the signals in each band. Higher the frequency lower is the dish size.😎
To know more about Ku band, C band and other basics you may download this pdf file <a href="https://www.scatmag.com/technical/techarticle-mar05.pdf" target="_blank" rel="nofollow noopener noreferrer">PDF</a>.

My doubt:
Can broadcasting companies communicate with our reception systems? I mean with our set top box?

I was wondering how could they descramble signals for certain users only and keep it encrypted to all others!😕