Internet Technology Explained

How Satellite Internet Works? [Technology Explained]

Guy McDowell 28-07-2009

satellite_dishSatellite Internet service appears to be becoming more and more popular. Once the exclusive domain of exploration companies and war journalists, there are now thousands of people with an extra dish on the home or RV. Part of the reason for this is that certain technologies have increased the bandwidth and decreased the cost.


Now, there are geostationary satellites. That’s a fancy word for saying the satellite stays still in relation to your position on Earth. You have to set the dish up just once and, barring windstorms or worse, the dish stays in constant communication with the satellite.

The latest way to communicate with satellites for Internet service is over something called the Ka band (pronounced kay-eh). The Ka band is a set of frequencies that are between 18.3 GHz and 31 GHz. More specifically, the uplink (that part of the call that is going from your home to the satellite) is in the range of 27.5 GHz and 31 GHz. The downlink (that part of the call that is coming from the satellite to your home) is in the range of 18.3 Ghz and 20.2 Ghz.

What the heck is a GHz? Giga Hertz. Giga for a 1,000,000,000, and Hertz for a cycle per second. Picture a wave on the ocean. It has two parts, the crest of the wave that comes high out of the water. Then there is the trough of the wave, which goes below the normal waterline. Now picture a cot and some Bud Light Lime….mmmmm. Okay back to school.

When the crest AND the trough are done passing over the same point in the water, that can be thought of as one cycle. Now imagine that happening in just one second. That’s a Hertz.  Now imagine that happening a thousand times in one second! That’s a megahertz. Now imagine that happening 1,000,000,000 times in a second! That’s a gigahertz. My brain hertz.

sine_waves real_wave
See the similarities?

Why do you need to know this? Well, those numbers relate to transmitting power and what the signal can carry for information. Just like in my first Technology Explained How Does Wireless Internet Work? Live in the country and wondering how wireless internet provides broadband coverage to rural areas? Here's what you need to know. Read More article, the lower frequencies transmit longer distances with less power, but aren’t capable of carrying a lot of information. That’s why the old 900Mhz phones don’t have the voice quality of the 2.6Ghz phones. Yet you could take those old phones down the block with you.


So, using the higher frequency ranges for satellite Internet allows for more data to be sent, giving us something close to high-speed Internet even if we’re an Alaskan recluse.

Because of the high frequency rates, that signal has to be stepped down and lose a bit of power before it hits the delicate electronics of the modem. This is done using a device that is on the dish itself as well as having a minimum of 150 feet of high-quality RG6 coax cable connecting the dish to the modem. So if you wonder why the installer used such a long cable just to wrap it up and drop half of it on the floor, well, this is why.

Something else you should know about is that Ka band satellite uses spot beams. A spot beam covers a specific area that really isn’t that big – about a third the size of Alberta. Each spot beam can support only so many users. If you hear that your buddy in Montana can get service, but you can’t because your spot beam is full, there isn’t much you can do about it. Also, you can’t move your service from spot beam to spot beam unless you are a certified installer. You will also need a clear line of sight to the satellite.

Here’s what the spot beams look like. As you can see, service is NOT available anywhere, like they sometimes advertise.


how satellite internet works

What’s the downside? Latency. What’s latency?  Gamers call it lag. It’s that time when your signal is going between your house and the satellite. Typically, it’s about 230 milliseconds or more. That doesn’t seem like much considering the signal is covering about 45,000 miles in that time. However, when it comes to things like VoIP or online gaming, it makes it nearly impossible to do.

Another downside is something called the Fair Access Policy or FAP. What this means is that your Satellite Internet Service Provider will put limits on how much you can download over a period of time – usually 24 hours. If you exceed that, they will automatically slow your speed down to something close to dial-up, to give other users fair access to the satellite. When this happens, you have been FAP’ed. So, if you are a chronic downloader, you’ll have to change your ways for satellite Internet.

Is it picture time yet? Of course it is.



All this for about $800 for the hardware and $50 a month for ongoing service. Not bad, when you consider bringing in a phone line down a logging road will cost about $10,000 a pole. However, if you want to put a self-pointing dish on your RV, you’re going to need to dig a little deeper as the hardware will run you about $10,000. You could try to take a stationary dish with you, but pointing the new dishes can take up to eight-hours to aim, and you must be a certified installer.

Photo Credits: cogdogblog, stewart, benchun

Related topics: Computer Networks, Satellite.

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  1. ricardo
    August 3, 2009 at 12:16 pm

    Just to improve the article:
    "Now imagine that happening a thousand times in one second! That’s a megahertz."
    It's not a megahertz, it's a Kilohert

  2. Cindy
    July 31, 2009 at 6:10 pm

    We have satellite internet access because it is our only available option in rural Vermont. FAP is anything but fair... and tech support is relatively useless because they are unable to vary from their forced-English scripted responses. Both DSL and cable have scouted our 'hood, and whoever gets here first is the winner of our account!

    • Guy McDowell
      August 3, 2009 at 1:11 pm

      I have heard that the FAP isn't necessarily fair, but then again, what is fair? That's a deep philosophical question.

      Offshore call-centers are generally horrible. Although, I have had great service once or twice.

  3. wafwot
    July 31, 2009 at 7:50 am

    We had Wildblue for about 2.5 years. The speed improvement over dialup made it worth the cost but the lag and weather related outages were annoying...not to mention the FAP. I was on Verizon's list to be notified when DSL became available to our home. It was a very happy day when I got the email stating that DSL was now a reality to us. All the problems of satellite, GONE! Speeeeed, reliability, lower cost, no FAP....heaven!

  4. Kurt
    July 29, 2009 at 1:45 am

    Purely out of curiosity, what sort of bandwidth does one expect to see downstream from a satellite? Does thie vary between geographies? Does differing levels of satellite capacity change an individuals performance? And reception via a dish makes sense but how does one transmit a signal upstream? What sort of bandwidth can one expect?

    Sorry for the rapidfire questions but this really article intrigued me because I always wondered what the mechanics were of DirecPC or HughesNet or whatever the heck it's called these days.

    • Guy McDowell
      July 29, 2009 at 7:57 am

      Depending on the package you get, upload speeds max out at 512Kbps. Download speeds can go as high as 3Mbps, as far as I know, with HughesNet. I'm only familiar with HughesNet in North America, so I can't say for certain, but I would think that as long as you are connecting to the same type of service, geography doesn't matter. Mind you, if there are trees or buildings or anything else in the line of site, you may not get a good signal or any signal.

      The LNB is capable of transmitting up to the satellite, but this is a relatively low power signal. Typically, a user will be sending things like text and mouse clicks, which don't require the higher bandwidth. 512Kbps is usually enough for most people. Typically this is the same for broadband landlines.

      Hope that helps!

  5. George Lowry
    July 28, 2009 at 2:53 pm

    The 45,000 miles is closer to the entire trip through the 'bent pipe'.
    Orbital altitude is closer to 22,000 miles.

    • Guy McDowell
      July 28, 2009 at 6:05 pm

      Yep, true. It used to be an accepted fact that all satellite communications would have a 3 second one-way delay. But with different frequencies, I guess that has changed.

  6. bits
    July 28, 2009 at 1:00 pm

    Nice piece. I learned.

    BTW: "a thousand times in one second" is a kilohertz (1 kHz)

    • Guy McDowell
      July 28, 2009 at 6:04 pm

      You are correct. I sit corrected. ;-)

  7. ...
    July 28, 2009 at 12:58 pm

    "FAP limit", hehe. I'm sorry for being amused by an immature joke.

    Anyway, this was very informative. The article makes satellite Internet look like a bad alternative, what with all the disadvantages presented.

    • Guy McDowell
      July 28, 2009 at 6:03 pm

      I just found out the OTHER meaning of FAP. D'oh!

  8. Tobey
    July 28, 2009 at 12:20 pm

    Very nicely explained. Thumbs up for the "Technology Explained" series.

  9. rowdytexan
    July 28, 2009 at 10:25 am

    As a current subscriber to HughesNet, I can tell you that the FAP limits SUCK. Right now, because I live in BFEgypt rural texas, I pay $100/mo with a 100mg/24hr cumulative bandwidth limit. Yes, its extortion, but better than dialup.

    That being said, I'll be canceling my service shortly. The proliferation of 3G wireless broadband providers means I can get 5gbs/month for +/- $60 with less lag and the bonus of portability.

    • Guy McDowell
      July 28, 2009 at 6:02 pm

      3G is spreading quite a bit and the price point is way better. Even formerly remote areas are getting coverage now. It's a great option!