Technology

The "No Spin" How It Works

A number of satellite internet providers will go into inordinate detail about how they provide asymmetrical (faster download than upload) high speed internet to anyone with a properly pointed sat dish and a view of the southern sky. Although the technology at a micro level can be intricate, most users just want to know from a reliable source whether they can do what they need to do with a satellite internet connection. Vsat U.S. is determined to sell you something that works. More importantly, we are not obligated to ANY provider, so we aren't motivated to shower you with a lot of unnecessary techno babble. You are most likely here due to a need for emergency communications, redundant backup or you have no terrestrial options (no DSL or Cable available). There are some technical things covered here that you should be aware of. The types of activities you engage over the internet will dictate what Vsat U.S. will recommend and what will work in the field.

All of our offerings for true IP Business Class Service are based on standards compliant IP connectivity for end-to-end transparency and compatibility. The less expensive products utilize the Digital Video Broadcasting (DVB) standard which was originally developed for one-way Television transmission. DVB works well if all you need to do is email and browse the net. But for the things many Corporations, Government Agencies and individuals connected to corporate office need to do, like VPN, VOIP and Video Conferencing, the logjam produced by DVB produces too much latency and there isn't enough upload speed to get the job done - period!

There are a myriad of acceleration and IP spoofing products (software and hardware) that Internet Providers have offered in a attempt to overcome the shortcomings of DVB transmission. These products are acceptable unless your activities include intense database inquiries and "chatty" programs like Oracle, Lotus Notes, and accessories like the Calendar in Outlook. Try remote printing with a Direcway or Starband setup in a VPN tunnel sometime if you want a load of frustration!

How can anyone call a 30-90 kbps or less upload capability "High Speed"? Who is kidding who here! By the time you throw in 1.5 to 1.8 second delay (latency) caused by the distance of the satellite from earth and all of the equipment needed at the Network Operations Center (NOC) to translate DVB packets into TCP/IP....whew, what a slow mess!

The IP connectivity we offer our Business Class customers is TCP/IP throughout the entire trip, eliminating the "log jam" at the NOC and on the transponder...lowering the latency to less than half that of DVB technology (475-700 ms) and allowing even the most demanding processes to work much like their terrestrial counterparts. Only in very demanding circumstances are acceleration products recommended.

Our site survey and discussion with a Senior Sales Engineer will sort these issues out with your company to insure you get what you need at a reasonable cost.

Even the most reliable satellite communications technology can sometimes be out-matched by the forces of nature. It's a phenomenon known as rain fade or rain attenuation - a weakening of the satellite signal as it passes through raindrops.

Rain fade is one of the most common, and often most misunderstood, phenomena to affect satellite signals. But the more you learn about the causes of rain fade, the better your chances are to lessen its impact on your satellite system.

The Causes of Satellite Rain Fade

Any satellite communications system network operator using a Ku-Band system (12/14 GHz or higher frequencies) will face the effects of rain fade at some time. But to understand why this weakening occurs with Ku-Band transmissions, you must first understand the causes of satellite rain fade. Two of the most common causes are listed below.

Scattering can be caused by either refraction or diffraction:

These different reactions ultimately have the same effect - they cause any satellite system to lose some of its normal signal level. Don't expect to lose your satellite signal every time it rains, though. Rain outage will only occur during the heaviest rains (convective and stratiform are the most predominant types) with only a small portion of the transmission path experiencing attenuation. In fact, of a typical satellite transmission path measuring 22,300 miles, less than .02% will be affected by rain fade. VsatUS has all but eliminated the rain fade issue with variable transmitters utilized on our larger dish offerings. Ask your VsatUS Sr. Sales Engineer for details.
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