Satellite Receivers are used in conjunction with a satellite dish to convert the satellite signal to video and audio that can be connected to a TV or monitor.
The signal from the LNB on the satellite dish arrives at the satellite receiver in L band, usually in 950MHz to 2150MHz frequency range.
This signal can be in Analogue or Digital. There are very few analogue channels left on satellite these days, most signals are digital, and usually comply to the DVB (Digital Video Broadcasting project) standard.

The Digital Video Broadcasting Project (DVB) is an industry-led consortium of over 260 broadcasters, manufacturers, network operators, software developers, regulatory bodies and others in over 35 countries committed to designing global standards for the global delivery of digital television and data services. Services using DVB standards are available on every continent with more than 120 million DVB receivers deployed.

Digital Satellite Receivers come in 3 main types-

1. Conditional Access embedded models. This is a satellite receiver usually with a card slot. The card slot takes a card, which unlocks the picture when you are viewing Pay TV or Optus Aurora services. There are several types of Conditional Access. The ones used in Australia are Irdeto, Seca, and Viaccess. Receivers supplied by the Pay TV provider are usually locked to the Pay TV provider the receiver is made for, and dont work on most other services. There are some receivers available that have the embedded Conditional Access, and that will also work on other Free to Air (FTA) Services. Two such models are the Homecast eM150IR, and the Arion AF3330. These two models have embedded Irdeto conditional access which is used for many Pay TV providers in Australia, and Optus Aurora.

2. Models with Common Interface (CI) Slots. These satellite receivers have one or two CI Slots. These slots are the same as the PC Card slots that you have on your laptop computer.  A Common Interface (CI) Module is inserted into this slot, and the smart card fits into the CI module. The CI modules are available in several encryption types, Irdeto, Seca and Viaccess being the most popular in Australia. CI Receivers will usually work on other Free to Air (FTA) Services. Some CI receivers are available with a Personal Video Recorder (PVR) function. The PVR will allow you to record programs onto the built in hard drive, for viewing at a later date. Recordings can be scheduled, and more advanced PVRs will allow you to record several channels at the same time, while vieiwing a previously recorded program. Trick functions suck as slow playback, fast playback, reverse playback, and tagging segments on the recording are aslo avalible. Hard drives of 100s of megabytes are available, with about 40 hours per 80 giga byte record rates.

3. FTA (Free To Air) digital satellite receivers. FTA receivers do not have a CI (Common Interface) slot in which to fit a CI module to take a smart card for Pay TV channels or Optus Aurora TV channels. These receivers are only for digital satellite signals with no encryption.