by Peter Xilliox
From the beginning, the VSAT industry recognized that VSAT installers would require training to transform a pile of cables, electronics, and antenna parts into a revenue-making VSAT terminal. Up until now, most VSAT installer training programs have focused on how to bolt up the components and mount parts to a roof or wall. These programs have provided instructions about how to make certain indicators illuminate and/or achieve minimum levels on meters or displays. However, unintended consequences of basic “bolt it up” training have become liabilities and have inflicted cost burdens on the VSAT industry. Without a good understanding of the fundamentals of the satellite link, it is easy for installers to accidentally cause interference and it is difficult for them to troubleshoot problems.
Swap-outs are expensive
Without solid training in the engineering fundamentals, technicians must resort to swapping hardware to troubleshoot problems. Often, the item removed is not actually defective, but it is returned anyway and joins an ever-growing pool of equipment of unknown condition circulating around warehouses, repair depots, and distribution centers. With today’s high-volume VSAT production hardware, simply evaluating and re-testing questionable equipment often costs more than manufacturing the item in the first place.
Cross-pol misalignment and adjacent satellite interference impact entire networks Even replacing all of the parts may not solve the problem. The dish might not be aligned accurately, cross-pol (cross polarization) may not be set correctly, or cables may have reflections or poor RF isolation due to improper connector attachment.
These errors don’t just affect the service quality of the particular installation — they can cause the entire VSAT network to be disrupted or can even create debilitating interference on the satellite or other satellites.
Return visits sabotage customer relations
Many times a simple “shotgun” approach to troubleshooting is not successful. A return visit requiring additional hardware or a technician with a higher-level of technical competency must be scheduled. Such repeat “truck rolls” can be extremely expensive to the service provider—they can also inflict great damage to customer relationships. Broadband satellite services must compete with terrestrial services, such as DSL and leased lines, which are generally simpler to install. The VSAT industry simply cannot afford a reputation of low quality installations and frequent return visits. Responding to the industry’s needs
Interference, lost hardware, site revisits, disgruntled customers, and viable hardware returned for unnecessary repair could all be reduced by ensuring thorough installer training. When technicians have a solid understanding of the fundamental concepts behind the VSAT terminal’s operation, they are much better equipped to perform tasks such as peaking the antenna accurately, setting cross-pol with precision, and interacting efficiently with a satellite operator’s Network Operations Center staff to resolve problems.
The Training Solution
In 2002, responding to membership requests to address the increasing problem of interference due to improper VSAT installations; the GVF initiated a Certified VSAT Installer program. comprised of a sequence of three-courses or “Levels.” Classes are given periodically in the U.S., South America, Africa, and other venues. The GVF Certified Installer database now lists over 200 certified installers worldwide.
To increase the reach and effectiveness of this program, the GVF has teamed with SatProf, Inc. to make the fundamentals portions (Levels 1 and 2) of this program available on-line over the Internet. SatProf was founded by satellite systems engineering professionals who possess more than 50 years of industry and in-house training experience. SatProf has developed techniques for highly interactive, real-time, simulator-based instruction delivered via the Web as Flash animations, a format readily available in all standard browsers.
The new on-line program goes further than conventional classroom training modes hampered by rigid class times and locations (with the attendant travel and lost labor costs). SatProf went a few steps further and discarded the notion that distance learning material should be “pushed” to a student passively watching an audio-visual presentation. Instead, SatProf has crafted interactive, animated training material, delivered to any Web browser in carefully sequenced courses.
SatProf courses can be accessed 24x7x365 from any location with Internet access. Each course focuses on presenting a fundamental understanding of the technical topics, with heavy doses of animation and virtual reality engines to support interactive ‘play’ with the instructional tools. The GVF on-line fundamentals training consists of two course levels. Level 1, entitled “Introduction to VSAT Technology,” presents an overview of satellite communications principles, and is followed by Level 2, “VSAT Installation Fundamentals.” To follow on, students may enroll in Level 3i, which focuses on the details of iDirect remote terminal installation, and Level 3S, which is conducted in a classroom setting and includes hands-on equipment skills exercises and testing.
Introduction to VSAT Technology – Level 1
In the Level 1 course, the student receives an overview of satellite communications, with an emphasis on VSAT applications, for technicians, engineers, managers, and IT professionals. The course presents an overview of the technology and history of satellite communications, focusing on Very Small Aperture Terminal (VSAT) networks and how they compete with terrestrial alternatives. The fundamentals of spacecraft operation, orbits, and coverage are explained, followed by an overview of ground equipment hardware and the alternative methods available for sharing space segment cost. The course concludes with a discussion of the main technical, economic, and regulatory factors of VSAT networks. The student is exposed to topics and terminology such as:
- Spacecraft Signal Path Building Blocks and Flight Control Systems
- Satellite Bandwidth and Capacity
- Spacecraft Orbits
- RF Spectrum Assignments allocated for Commercial Satcom
- Channel Latency
- Regional Coverage Footprints
- Analog/Digital TV, IP, Voice, Media Satellite Services
- Advantages of SATCOM
- Disadvantages of SATCOM
- Earth Station Varieties
- Satellite Transmission Access Techniques
- Digital Video Broadcasting (DVB)
This on-line course consists of animated & interactive Flash pages presented in a self-paced sequence. During the course, the student is encouraged to explore diagrams using mouse rollovers, turn knobs, adjust antennas, and tune test equipment, through the use of the on-line simulator functions. Figure 1, above, is from the Level 1 Training course and uses animation to explain how time-division multiple access (TDMA) is used for “inbound” data from VSATs to a hub. Similar learning pages explain SCPC, DAMA, TDM, and CDMA
Review quizzes are given after each of the ten lessons and a final test is given at the end of the course. The prerequisites for the course are simply an interest in satellite communications. Level 1 consists of approximately 100 learning pages, requiring 5 to 10 hours of study.
VSAT Installation Fundamentals - Level 2
The Level 2 course presents the fundamental knowledge and skills that all VSAT installers need for high-quality, interference-free installations. As is the case with the Level 1 training, this course consists of animation and interactive Flash pages presented in a self-paced, on-line format. The animation and simulator-based interactivity are used even more extensively to bring critical technical concepts to life. The Level 2 student learns fundamentals of signals, noise, modulation, antennas, propagation, and link budgets. The key techniques necessary for a high quality installation are treated in detail, starting with the site survey, continuing with equipment installation and accurate antenna pointing, carrier lineup and cross-pol checks, indoor electronics installation, and IP network configuration concepts. The course concludes with a review of the installation process, troubleshooting tips, and maintenance guidelines. The student learns topics and terminology such as:
- Decibels (dB)
- Carrier to Noise Ratio and Digital Eb/No Ratio
- Digital Signal Primer for BPSK, QPSK, 8PSK, 16QAM
- Antenna Primer
- Polarization and Frequency Reuse
- VSAT Hardware Variations
- Forward Error Correction (FEC) Coding and Channel Bit Error Rate (BER)
- Rain Fading and Link Budgets
- Site Survey Basics, Use of Compass
- Virtual Antenna Pointing Exercises
- IP Networking
- Trouble Shooting
The screen shown in Figure 2, above, is a sample page from Level 2—The “sky view” shows how the antenna beam overlays the satellites. This page is one of a sequence explaining how to use both simple sat finder and signal ID meters.
As with Level 1, review quizzes are given during each lesson and a final test is given at the end of the course. The student should expect to allocate 15 to 30 hours to navigate the approximately 180 pages, depending upon the pace the student finds comfortable.
VSAT Foundation Building
The Level 1 and Level 2 courses provide a solid foundation for understanding the engineering basics governing VSAT system operations. When VSAT installers are armed with a better understanding of the systems they are installing, the VSAT industry can expect to enjoy the economic benefits associated with less ‘good hardware’ circulating around for repair depots, fewer inefficient (or interference causing) terminals installed, and a happier VSAT customer base.
Students may self-register and start the courses immediately by going directly to the GVF Training Portal. A free guided tour containing additional sample pages from the GVF on-line classes, brochures with detailed class curricula, and information about discounts for developing country students are also available at the GVF Training Portal.
Pete Zilliox has 35 years satellite systems engineering experience with Hughes Aircraft Company, Collins Radio, Dalsat, Zilliox & Associates, and Andrew Corporation. In 2006 he founded SatProf, Inc. (www.satprof.com) with Ralph Brooker. SatProf is a provider of online, interactive training content and advanced engineering consulting to the satellite industry. He received a B.S.E.E. from Penn State and an M.S.E.E. from USC.