Let’s say you live in a rural area not served by either a local cable company or a fixed wireless provider. Your only choices to surf the Internet besides dial-up are either satellite ISP or digital subscriber line (DSL) provided by the local telco.
Which option do you choose? Evaluate the pros and cons of each below to decide which technology optimally serves your household’s web usage.
Satellite and DSL Internet Access
Satellite and DSL use two very different technologies to deliver Internet service to their subscribers.
A satellite ISP connects to their customers via super high radio frequencies, relayed through a geostationary satellite orbiting above the earth’s equator. The roundabout journey data travels via satellite from one’s household to an ISP server and then to a URL destination located on a distant continent and back often extends over 100,000 miles.
A terrestrial-based technology such as DSL, on the other hand, uses twisted copper pairs originally built to serve the public switched telephone network (PTSN), aka plain ol’ telephone service (POTS). One difference between DSL and POTS is that, like a dedicated data circuit such as a T1, a DSL connection is always “on” and not switched like a typical voice call.
Both technologies require CPE modems. Legacy DSL required the use of a “splitter” to “split” a voice path from the DSL connection for phone calls. New technology now allows splitting to be done from the telco CO. However, a “splitterless” DSL connection requires the use of a DSL filter.
From “The Get Computers & Internet,” here’s a video primer on the differences between DSL, T1 and satellite Internet access:
Is Reliability a Liability?
While neither service offers an ironclad SLA (unlike telco T1s), each can have its particular reliability issues.
With satellite Internet, adverse atmospheric conditions between the line of sight (LoS) of the dish and the orbiting satellite can attenuate radio waves connecting the two points. Rain, smoke, fog and even super-heated air rising from the earth’s surface can disrupt a satellite’s signal. Foliage and buildings also pose LoS issues.
With DSL, distance from a household’s CPE to a DSL network node (AT&T calls it a video-ready access device or VRAD) is critical. DSL line loops can travel as far as 10 km (6 miles) without the need for a loop extender aka repeater. Its network architecture is based on discrete multitone modulation (DMT).
We explained in a previous IAG article, “As distances… increase, data transfer speeds slow (and) decibel loss increases with distance until finally the signal at the customer’s premises can’t synchronize with the head.” Ergo, no Internet.
Other DSL reliability issues? The condition and gauge of the copper wire serving subscribers. If you live in a long-established neighborhood, the copper delivering electrical signals your area could be decades old. Too, heavier gauge copper wire (e.g., 22 gauge) works better than lighter gauges (e.g., 24 or 26 gauge).
Often, telco techs have to replace degraded wiring from pole to the customer’s interface to maintain a constant, consistent connection. You also may need to replace wiring in your home.
Satellite and DSL Internet Connection Speeds
The two satellite ISPs currently available to consumers — HughesNet and Viasat — now deliver substantially faster speeds than just a few years ago. HughesNet provides download speeds up to 25 Mbps while Viasat renders up to 50 Mbps. Their service tiers uniformly offer 3 Mbps upload speed.
With DSL, YMMV. Depending upon loop distance and technology in use, DSL connection speeds vary widely. Legacy DSL (a 1990s technology) furnishes speeds no faster than 6 Mbps down (although it’s said that the protocol could go as fast as 20 Mbps).
AT&T has unleashed faster (albeit plagued by shorter loops) DSL known as very-high-bit-rate DSL (VDSL) and VDSL2. The table below depicts their faster speeds:
|
Version |
Standard |
Download |
Upload |
Approved |
|
VDSL |
ITU G.993.1 |
55 Mbps |
3 Mbps |
11/29/01 |
|
VDSL2 |
ITU G.993.2 |
100 Mbps |
100 Mbps |
02/17/06 |
|
VDSL2, Annex Q |
ITU G.993.2, Amd 1 |
300 Mbps |
100 Mbps |
11/6/2015 |
Note that VDSL and VDSL2, Annex Q are examples of asymmetric DSL (ADSL) while VDSL2 is symmetric (SDSL).
Also be aware that to receive anywhere close to the speeds shown above, you need to be quite proximate to the DSL service node, viz, no greater than 1 km (0.62 miles) before the signal begins to degrade. Legacy DSL is more forgiving; the loop travels as far as 2.25 km (1.4 miles) before signal degradation occurs.
“Not cheap without reason, nor dear without value.” — Afghan proverb
While DSL service tier pricing varies wildly depending upon telco provider, the cost of satellite Internet comes down between two providers: HughesNet and Viasat. Long story short: you’ll pay more for satellite ISP while at the mercy of onerous data caps by comparison with DSL.
You’ll find out just how “dear” satellite Internet is should you stream data to devices that devour bandwidth, like UHD TVs or applications such as OTT media. It won’t be long until you run up against a data cap. Then, your satellite ISP “throttles” your data down to 1-3 Mbsp until next month when data caps reset. Once that happens, you either pay handsomely for more data or watch TV OTA.
Coda
Several years ago, your intrepid tech blogger wandered the hinterlands of Indiana, Nebraska and Iowa, installing Adtran TA5000 DSL bays in telco central offices. Later, residing on the fringe of civilization, he subscribed to HughesNet Internet service.
So, the reader may ask: which one would he choose? The answer: it depends. Nobody really knows how fast a home’s DSL service will be. So much depends on the distance between CPE and the serving network node, the condition and gauge of the copper wire serving the subscriber and the DSL technology used.
On the other hand, speeds from satellite ISPs have greatly improved in the past few years. Yes, satellite service is generally pricier than telco DSL. If latency (and cost) isn’t an issue, the odds are that one will receive faster speeds from a satellite connection unless the subscriber is within shouting distance of a DSL network node.
In sum, you’re more likely to get “true” broadband from a satellite ISP than from DSL. But you’ll be subject to more restrictive data caps and likely a higher cost with satellite Internet.