Understanding How Satellite Broadband Works

satellite broadbandSatellite Internet has taken on nearly mythical status as there are people that exaggerate both the virtues and the downfalls of the technology as whole, often without proper education on the subject.  Consider this your official primer on the subject, a sort of Satellite Broadband 101 if you will.  This article will cover the basics of the technology as well as dispel some of the aforementioned exaggerations on both sides to give you a good, clear, honest picture of how satellite broadband looks.

Basic Broadband Primer

Before you can pick the best satellite broadband out from something sub-standard, you need to understand the basics of how signals travel.  All electrical and light based signals travel at roughly 186,000 miles every second.  Yes, these signals do a quarter million miles in about the time it takes you to clear your throat.  That might seem well and dandy on the surface as a nifty factoid, but how does it relate to broadband?  Well, signals that travel through wires and fiber optics might take a slightly convoluted path from your home or place of business to the backbone of the Internet, but that distance is usually measured in just a few short miles.  With only a few miles at stake, that signal gets there pretty quick at the speeds we are talking about for signals.  Let’s move on to looking at how this impacts satellite broadband systems…

Satellite Broadband 101

Satellites that are used for relaying broadband data back and forth to end users almost uniformly orbit the Earth in what we refer to as a geostationary orbit.  This means that the position of the satellite seems to be constant from the point of view of someone on the ground.  This relative stability is required in order to keep the line of sight constant.  Without a line of sight, no signal can be sent without some sort of transmission media such as a plastic-sheathed metal wire or fiber optic conduit.  This might not seem impressive, but when you factor in that the general range of altitudes for last-generation geosynchronous satellites starts at about 22,000 feet, you are essentially adding something on the order of 44,000 feet of additional distance that a signal needs to traverse doing a round trip over what it does in a more terrestrial form.

How does this impact performance?  Well, a little math will tell you that 44k over 186k gives you something like 0.23.  That is a measurement in seconds, or roughly a quarter second.  This is a minimum delay when using a satellite in that high orbit and is a non-negotiable physics issues that we currently have no technology to circumvent other than the development of low-flying satellite.

Low Flying Satellites

There are entirely new generations of low flying satellites that are already seeing deployment, but there are some sacrifices.  The biggest sacrifice is in overall coverage, and that only makes sense because of the whole line of sight issue.  Simply put, the higher you go, the more people have line of sight on you.  If you are a satellite providing broadband, this means a good return on investment, and satellites are not cheap to build or deploy.  The new generation of satellites currently being fielded by companies orbit at a much, much lower altitude of about 1000 miles instead of the more traditional 22k+ miles.  The difference of a few thousand miles to a signal is far less noticeable and may not even be perceptible to the human eye.

A financial downside exists to this arrangement though.  As previously mentioned, these satellites are expensive and their cost is a business expense that is distributed over many users and over many years.  If fewer users have access to a given satellite, the cost must go up in order to balance the books.  Even lower altitude inexpensive relay satellites and ultra-high flying unmanned solar-powered aircraft may eventually rebalance these costs

Interference vs. Frequency

While we should now understand the concept of line of sight and have a good understanding of how it impacts the business of satellite broadband, we need to also consider the effect of weather and other forms of interference.  One of the primary audiences for early satellite systems happened to be the entire outdoor crowd.  These people would be campers, etc. and would often repot that tall trees and other obstacles would create reception and transmission issues.  The use of different and sometimes multiple frequencies has greatly reduced the impact of everything from weather to tress, but both may still degrade overall signal quality to an observable amount, but the signals still tend to get through when previous generation systems would be utterly out of commission.