“I’m Confused...”

(Most) All the answers and probably more than you want to know about your satellite, video-conferencing and webstreaming questions…

September  2001

As a first time or even longer term civilian, military, or federal government customer for our free satellite teleconferences, we often get questions about connectivity options for your location.  Let’s discuss each option in detail below:

Satellite Connectivity:

There are generally two types of satellite programming…  Open or Closed

Open programming refers to programs that are broadcast in the clear or in the public domain where, if you have the proper equipment and the satellite coordinates, you can usually tune in the program.

Closed programming refers to programs that are encrypted or send across special satellite platforms usually not available to the general public.  Examples include Pay-Per-View TV programming you might find on DBS DirecTV or Dish TV, programs offered by the National Technological University or NTU or other satellite programming offered on Business Television (BTV) Networks like those operated by Ford, Home Depot, the US Military, Federal Government and other corporate and governmental providers.

There are two types of satellite signals…  Analog or Digital

Analog signals are the first generation of satellite transmission.  The satellite dishes receiving these signals are generally referred to as C/KU analog dishes, those moveable, 5-12 foot, mesh or solid steerable dishes we used to see a lot of in rural neighborhoods.  There are still 10,000 – 12,000 of those in operation around the country and likely have another 3-5 years or more of useful life left.  We have about 7500 C/KU locations in our database.   These are generally what most civilian operators use although some military and federal locations also still operate them.   They can still be found in a number of locations.  See:  

http://www.dlnets.com/satinfo.htm 

Digital signals are the second generation of satellite transmission.   DirecTV and Dish TV use digital signals.  So do most BTV operators.   And what’s really confusing some folks, some C/KU sites are upgrading to digital as well so some C/KU sites could be analog, digital or both depending upon what type of set-top boxes or IRDs (Integrated Receiver Decoders) they are using. (Hopefully the operators did not toss out the analog IRDs when they upgraded).

This is what a typical IRD or set top box looks like.   Manufacturers include Drake, Scientific Atlanta, Chapparel, Sony, among others.

There are a number of different satellite platforms… including DBS, BTV, and C/KU. Let’s examine each in turn.

Direct Broadcast System (DBS) satellite platforms are those 18-36 inch round or oval dishes operated by DirecTV, Dish TV and others.  They use a digital signal.  They are generally NOT USED by public domain program providers due to the expense of the satellite space segment time involved ($2000 or more per hour plus backhaul charges), but occasionally a provider will include these networks within their connectivity options.  They look like these two on the left and right of this steerable, mesh C/KU analog dish seen in the center.

The oval dish on the left usually offers one-way down, high bandwidth Internet connectivity for webstreaming, but more about that later.  This example probably also receives both national and local programming as indicated by the dual feedhorns shown.

The RCA DBS digital dish on the right only delivers a straight television signal.

C/KU Analog satellite platforms come in a variety of shapes, sizes and colors.  These mesh or solid 3-12 foot or larger dishes are what is most commonly used within the civilian world to receive the types of programs we co-ordinate for our many.   They look like this:

The dishes seen above are designed to move to track and capture various satellites like Galaxy 3R, SBS-6, GE-2 and other satellites located in the “Van Allen Belt” in geosynchronous (stationary) orbit some 22,500 miles above the earth.   If you look carefully on both dishes, you can clearly see actuator arms which move the antennas to align to the designated target satellite.

If you look at the diagram below and think of the continental United States as lying directly below this chart in the center of the page and then imagine the dishes above looking up at about a 45 degree angle with a clear line of sight in a southerly direction for most US locations, you can imagine how the dishes have to be steered to find each target satellite.   Satellite operators are continually launching new satellites to replace older ones and/or moving the older ones to new locations.  Most new satellites are both C and KU capable (called hybrids) with more and more powerful transponders than the ones they are replacing. 

To receive these signals, you need the correct C/KU analog satellite coordinates similar to the ones we send registered C/KU analog customers via email 5-7 days prior to each program we coordinate.  They look like this:

These C/KU satellites are operated by companies like Hughes, PanAmSat, Loral and others.  They are continually launching new satellites as demand increases and as the lifespan of their older satellites come to a close. (Even at 22,500 miles, satellite orbits are in continuous decay and they only hold so much repositioning fuel.  Baring any catastrophic failures (rare, but they do happen, - remember the failure of Galaxy 7 in 1998 when many pager and cell phone networks were effected?) satellites generally have a lifespan of 10-15 years.)   In addition, operators want to take advantage of new technologies, increased capacities, etc.  Older satellites only had a capacity of 10-16 transponders/channels, and were only capable of analog transmissions.  The newly launched satellites have a capacity of 24-28 transponders/channels, can be both analog and digitally capable, operate on both C-Band and KU-Band, and are usually more powerful in signal.  (And they can cost $300-500 million!!)

One of the main reasons why C/KU operators fail to acquire our programming is that  they fail to update their automatic steering software to accommodate the changes that satellite operators make in repositioning and orbiting new satellites.  For example,  Galaxy 7 is dead and gone replaced  by Galaxy 11 in 1999.  Galaxy 4R replaced Galaxy 6 at 99 degrees West as Galaxy 6 was moved to 74 degrees West as its end of life nears in 2002.  For the small amount of money involved, it generally pays to have your local satellite provider update your automatic steering at least annually to keep up with these changes

And while your satellite provider is there, why not have him (or maybe her) check over the antenna systems in addition to upgrading the steering software.  The main enemy is water which get into your steering motor housings and short out the actuator connections. If you don’t move your dish often, the actuator arm can also become stuck through corrosion or from freezing water in cold weather.  The arm should be periodically cleaned and lubricated.  There are a number of other preventative maintenance steps that should also be taken through an annual maintenance inspection, but it is more likely your satellite provider will do these.  The point of this paragraph is just to make you AWARE that steerable satellite systems in particular REQUIRE periodic maintenance and updating, but a larger percentage of  C/KU sites in my experience fail to perform these tasks than those that do. 

Also, a word about C/KU analog, and C/KU digital reception.  Most C/KU analog dishes are capable of BOTH C-Band and KU-Band reception.  Depending your location, the footprint of the satellite involved, and the signal strength for your location, your satellite downlink operator might elect to use either the C or KU analog bands.  Or they might try both and select the one with the best combined audio and video signal.  This photo illustrates what a typical satellite “footprint” with relative signal strength looks like.

For most C/KU analog downlink operators, especially those in the Western United States, C-Band is generally the preferred band.   Some program providers are, in fact, moving entirely away from providing KU-analog coverage of their programming.

Rain especially effects KU reception.  Fog and and even heavy rain laden clouds can effect the signal strength of KU transmission.  So can heavily falling snow.

Examples of program providers still using C/KU analog platforms include the Bureau of Land Management (primarily in the Western United States) and the Veterans Administration (VA Hospitals).   Organizations like the Federal Emergency Management Agency (FEMA), the Centers for Disease Control (CDC), and the Federal Bureau of Investigation (FBI) among others, operate “ad hoc” C/KU networks relying upon the still vast network of C/KU analog dishes operated by colleges, universities, K-12 schools, hospitals, Extension services and other public agencies to view their programs.

As previously mentioned, some networks, like the PBS Adult Learning Channel for example, are upgrading their C/KU networks to operate on a digital signal only.  But to receive these digital signals you need a General Instruments DSR 4000, DSR 4200V or DSR5 receiver or other special digital receiver and be authorized by the provider, in this case, the PBS Adult Learning Service.   Unfortunately, this means that more and more programming will become less and less available to the public at large as providers and networks gradually upgrade to digital reception which is often encrypted. 

CDV Satellite Platforms…or Compressed Digital VSAT satellite platforms are generally “closed” or encrypted networks operating fixed, solid digital dishes normally about 1.2M in diameter or sometimes larger depending upon their location in the in the designated satellite footprint.  Locations on the fringe of the footprint, like in Alaska or Hawaii for example, often need a larger dish such as the one seen on the right below.

Where possible, roof mounts are preferable for a clearer line of site to the horizon and to avoid vehicular damage and other interference ground mounts can incur.

Ford Motor Company and General Motors each operate one of the largest closed, fixed digital satellite networks in the world with over 5,000 (Ford) and 9000+ (GM) locations throughout North American.  Next time you pass a Ford or GM  dealership, look up on the roof and see their dish.   Home Depot is another large corporate operator.

Within the US Military and Federal Government, most of the military services and many government agencies operate closed, fixed dish digital networks.  A number of military services to include the U.S. Army, Army National Guard,  Air National Guard, U.S. Air Force, Air Force Reserve, Defense Logistics Agency and selected U.S. Coast Guard sites have partnered with other federal agencies to include the FAA, Department of Energy, Department of Justice, US Courts, Fish and Wildlife, National Park Service, and others have grouped together to form a consortium called the Government Education and Training Network or GETN.  The GETN members all operate on a common digital satellite platform capable of receiving each other’s programming. Taken together, they account for over 1,000 downlinks around the country.  Whether called the “Satellite Education Network (SEN) by the US Army, the “Warrior” network by the Army and Air National Guard, or the Air Technology Network (ATN) by the USAF and Air Force Reserve, they are all one in the same…if they are part of the GETN network.   For further information about this network including an expanded Powerpoint Presentation of how a typical network works, see this web site:

http://getn.govdl.org           (…when the server is operating)

Does this mean that all government agencies operate on the same digital platform?

Unfortunately for taxpayers, no.  As described above, some agencies still operate C/KU systems.   Other agencies, like the US Post Office, the Social Security Administration, the VA, and others operate closed digital systems of their own, but they are not directly compatible with the GETN systems.  

Fortunately, there are some creative ways to combine both analog and digital signals of different satellite platforms.   In the business, we usually call this making a “turn”  or “flipping”  a signal received from platform and converting it to another.   To do this however, requires a lot of various antennas, receivers and someone with the technical skills to accomplish it.   One of the best in the business, at least in the government and military is the U.S. Army’s Satellite Education Network (SEN) at Ft. Lee, VA.   They have an extensive “antenna farm” (seen on the left below) that can capture both digital and analog signals from a variety of platforms and then rebroadcast the reformatted signal.  They can “flip” a C/KU signal to CDV digital or vice versa.   (Here’s a puzzle.  How many satellite dishes (in whole or in part) can be seen in this picture of SEN’s satellite farm on the left?)  See the answer are the end of the satellite section.

Ed McDowell, SEN’s Operations Manager and his satellite tech, Vic Boggess, seen here in the right hand picture, do a great job for the GETN community.  Other locations, like the Air National Guard at McGhee Tyson ANGB in TN, the FAA in Oklahoma City, OK and the USAF at Wright-Patterson AFB in OH also have a similar capability though perhaps not quite as extensive as is Ft. Lee’s.

On some programs, we might be using as many as FOUR different satellites to deliver a given program.  So…if during the thirty minute test pattern your particular satellite doesn’t come up with the correct test pattern slate in the first five minutes or so… and your operator is competent and their systems are all up to date and functional (with C/KU systems), it usually means we are all working frantically behind the scenes trying to align the “turns” we need on all the satellites.  Generally, this only takes a couple of minutes, but occasionally IGOR the satellite GOD likes to play with our electrons and it can take longer.   Factors such as heavy snow or intense rain over one or more of the uplinks involved can make this more of a process than we normally expect.

The digital systems, especially those used in the GETN military and federal networks, are usually fixed dishes. Unlike C/KU analog systems, which have to be steered using satellite coordinates like those previously shown above,  the GETN systems must be electronically “illuminated” or “authenticated” from a central systems management center to receive any programming at all other than the “home channel” which for GETN networks is CNN.  They are usually much more “idiot-proof” that the C/KU dishes.

GETN network managers have several choices when it comes to illumination.  First, they can request and authorize a “global” illumination which will cause all the of the IRDs in their network to electronically switch all at once to a designated program.  When that program is over, the units automatically switch back to CNN, the home channel.  Some networks, especially those in the military where redundancy is important, have from two to four IRDs per site all operating from the same dish and the same satellite.  This means that any given site can receive from two to four different programs simultaneously, which offers great flexibility.   Each site in the GETN networks has a designated site ID with a two letter prefix that designates a particular network. For example, AY-001A is a US Army site;  FA-014A is an FAA site, AN-060B is Army National Guard, and so forth.    Networks and sites having multiple IRDs designate them as “A”, “B”, “C” etc.   Each IRD also has a “UA” number such as  2750516-8.

Using the flexibility of multiple IRDs, network managers can set up “tiered” illumination groupings for special events.  For example they can reserve their “A” IRD tier for network wide broadcasts or home network broadcasts, while designating their “B” IRDs for occasional or one time programming or for Interagency programming.  Network managers can also build customized illumination listings that may illuminate only a given set of 10 or 20 sites designated to receive a program.

One important security feature of the GETN networks is that, unlike unencoded C/KU analog signals, one GETN network cannot view the programming of another network without authorized permission of the original network provider.  The GETN network cannot as yet transmit Classified programming, but the Department of Energy and the USAF are working towards this capability.

When it comes to Interagency GETN “shared use” programming, most GETN network managers allow their sites to be “cross illuminated” on a site by site basis schedules permitting.  That’s why when site coordinators register for a program, they need to provide their site ID… like AY-045B…and their UA number, so we can build the customized illumination list that will deliver the program requested.  We turn this list in to GETN’s central satellite operations center whose engineers must in turn build their own list.  That’s why we ask those of you using GETN downlinks to plan ahead and register at least 72 hours ahead of the broadcast date and time.  Registration inside that window will not guarantee your site’s illumination.

Network managers are furnished with a listing of their sites that have registered for any Interagency “shared use” GETN  program.  They reserve the right to delete any of their sites if programming from their own network takes a higher priority.

The beauty of the digital system is that is nearly idiot proof.  It your system is on and CNN is being broadcast, it is working.  The dish is smaller.  It doesn’t have to be steered. There are no moving mechanisms to malfunction or corrode.  Its software can be upgraded without a technician’s site visit and generally the digital signal is cleaner and crisper.  And if your site fails to illuminate as scheduled, it can generally be fixed within a minute or two through a phone call (provided you call the RIGHT number) and the near instantaneous sending of another authentication signal to your dish.

One tip from real world experience.  While most GETN dishes are roof mounted, some are ground mounted.  And yes… parking a large semi truck and trailer in front of the dish WILL disrupt the signal.   Heavy rain or snow over an uplink or a downlink can also cause the signal to “sparkle” or “tile” somewhat, but the weather is generally far less of a factor than it is with C/KU dishes.

So what does a satellite uplink look like?   They come in several variations, both fixed and transportable.   Here are a couple of examples of fixed uplinks.

The picture on the left is the GETN digital uplink at the Air National Guard Professional Education Center at McGhee Tyson ANGB, TN.  It is fixed on a single satellite (Telstar 4) and never moves.  The two soldiers pictured give you an idea of the size scale.  The uplink on the right belongs to the Federal Emergency Management Center (FEMA) at Emmitsburg, MD.   It is a steerable, analog uplink.  Note that both uplinks have a dedicated “loopback”  dish so that their operators can monitor their own signals for audio and video levels.  FEMA’s analog dishes rotate.   GETN dishes do not rotate.

One final thing to remember about satellite teleconferences.  They are ONE-WAY VIDEO, TWO WAY AUDIO.  This means that the downlink audiences see and hear the presenter, but the presenters at the uplink studio cannot see the downlink audiences.  The presenters can hear the remote audiences through a continuous telephone bridge call in small events (30-40 sites) or interact by 800 calls, fax, or email in large events (100 or more sites).

Although this simple audio convener and its microphone may not look all that sophisticated, it has the ability to compensate for the slight audio latency delay that occurs with satellite transmissions.  It also automatically mutes the TV monitor’s audio and prevents echoing as well as one site from “stepping” on the audio of another while providing a high level of audio clarity not possible with just a  “speakerphone.”

These PTT microphones are simply plugged together in a series and use a plain old telephone (POTS) service line to link back into an audio bridge to provide direct interactivity between the presenter(s) at the satellite studio origination point and the audiences at the remote downlink locations.  It graphically looks something like this:

Again, this type of network is used for satellite teleconference events with a limited number of downlink sites, typically within the same network and usually limited to the capacity of the servicing audiobridge. It provides for a much higher level of interactivity between receiving sites and presenters.  When verbal interactivity is actively designed into the presentation using the old adage of “early and often” inquiry, the sense of distance and the lack of visual interaction can be overcome by experienced instructors.  

When satellite teleconferencing events cross or combine different satellite platforms such as C/KU analog and CDV Warrior digital platforms from several networks and have hundreds of downlink sites and sometimes thousands of viewers, this level of continuous on-line interactivity is not practical.  They instead rely on 800 number calls, faxes, and/or email for interactivity.

If you have additional questions that have not been answered here, please go to this web site and send your question.  See: www.dlnets.com

If your question has not been previously answered, we’ll post it and the answer here.

SEN SATELLITE PUZZLE ANSWER:

(From the SEN pictures… how many dishes can be seen in that picture of SEN’s satellite dish farm?  …TEN!   …and that’s not counting the three more you can’t see behind the building!!)

This leads us next to TWO-WAY AUDIO, TWO-WAY VIDEO, typically called…

VIDEOCONFERENCING:  

(Still under construction…More on this when we have a little more time to write about it…)

and…

WEBSTREAMING:

(Still under construction…More on this when we have a little more time to write about it…)

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