Satellite TV developments

The manufacturers of onboard satellite TV systems are involved in an endless game of catch-up as the technology used by the satellite program providers evolves. These sat TV makers strive to provide additional viewing choices with access to high-definition (HD) programming. Power voyagers, who generally have more room to mount antennas than sailing voyagers, are natural early adopters of this technology.

Two of the major manufacturers of satellite TV systems, KVH Industries and Intellian Technologies have addressed the challenge presented by DirecTV’s decision to relocate its HD programming to two Ka-band (18.3-18.8 GHz) satellites and to leave its standard-definition (SD) programs and the essential TV guide information on its Ku-band (11.7-12.7 GHz) bird.

KVH has taken an impressive engineering approach to the problem of gathering signals from three satellites and two frequency bands. KVH’s new HD7 system can simultaneously receive signals from all three spacecraft, the two Ka-band and the Ku-band satellite.

Intellian, meanwhile, has taken a different path, using their d-Series system, including the 19.7-inch dome antenna to receive HD and SD programs from any of the three satellites, using the approach of rapidly switching between satellites.

DirecTV’s realignment of programming among satellites to take advantage of the greater bandwidth available on the Ka satellites was made technically and commercially feasible by the ability of the antennas used for home TV systems to simultaneously receive signals from the two Ka satellites (positioned at 99° and 103° W) and the Ku satellite at 101° W.

A challenge for marine systems

While the move of HD programming to the Ka-band satellites required no alteration to fixed-mount home antennas, marine satellite TV systems were adversely affected. To receive signals from all three satellites, boats would have to use a separate antenna for each of the satellites on which DirecTV programs are broadcast or accept the disadvantage imposed by being able to receive a signal from only one bird at a time. Switching from a program being broadcast on one satellite to a program on a different satellite will impose a delay as the antenna shifts to and locks onto the newly selected satellite. The fact that the programming information on the Ka-band satellite would not be available when watching either of the Ku-band birds creates problems if the schedule information stored in the receiver expires while the system is locked onto one of the HD broadcast satellites.

The multi-satellite signal source, single-signal reception situation would also make it difficult if not impossible to program a digital video recorder (DVR) for automatic recording since access to the Ku satellite and at least one of the Ka satellites would be necessary for HD programs.

Some existing mobile satellite TV systems (those installed on rather large boats) succeed in tracking the three DirecTV satellites, accommodating the 4° spread in their orbital positions with the use of relatively large-diameter, long-focal-length antennas, similar to those used in terrestrial systems. For example, the 22.5-inch by 32.5-inch Sea Tel DTV04 HD antenna is housed in a 50-inch-diameter, 51.75-inch-high dome and weighs 207 pounds.

The advantage of being able to simultaneously track and receive signals from two Ka-band and one Ku-band satellite presented a technical challenge to KVH that has been met with the development of the HD7 system, a remarkably small, 24-inch diameter parabolic antenna housed in a 26-inch-diameter, 27-inch-high dome that weighs only 61 pounds. (Specifications that will evoke applause from any installer).

The design and construction of the HD7’s antenna dish is quite conventional; the primary innovation is in the design of the sub reflector and the use of a triple path dielectric feed to a tri-satellite LNB (Low Noise Block). In most Cassegrain reflector antennas, the signal is acquired by the concave, parabolic dish (the primary mirror in a telescope) and focused on a secondary, usually hyperbolic reflecting surface for delivery to the receiver. However, the secondary reflector in the HD7’s antenna is specially contoured to focus the energy from three satellites within the antenna’s field of view into three separate dielectric feeds that deliver the detected energy to the three-channel LNB mounted on the rear surface of the primary reflector.

Three at once

The ability to simultaneously receive the signals from all three satellites reduces the time needed for initial acquisition and re-establishment of a solid connection should extreme sea or atmospheric conditions interrupt reception. However, the antenna control servo system must be both fast and precise to ensure consistent reception in rough sea conditions.

Receiving all three DirecTV satellites at one time becomes especially important when viewers want to watch different programs, broadcast on different satellites, on multiple TV sets. With signals from all three DirecTV satellites available from the antenna control unit (ACU), connections can be made to up to eight HD tuners without need for an expander box. Three-satellite reception is also required when a digital video recorder is set for unattended operation, requiring access to the program guide and, depending on the channel selected, access to all three channels. While a single antenna solution, using a relatively narrow view antenna to receive the signal from one satellite at a time will work for viewing programs broadcast on that satellite, switching to a program being broadcast on a different satellite will entail a delay as the onboard system acquires the new satellite signal and it is unlikely that preset timer recording on a DVR will work properly.

The initial setup of a satellite TV system, or resetting if necessary when away from your home port can be tedious. The KVH HD7 manages the initial (and future) system setup process via an Internet protocol (IP)-enabled antenna control. The setup process can be accomplished directly on the ACU or via the Ethernet connection using a laptop computer. A free TracVision application for the Apple iPhone or iPod Touch provides wireless access to the ACU. Software updates can be loaded into the system over the Internet, via the iPhone/iPod Touch app or by inserting a flash drive into the ACU’s USB socket.

In addition to receiving DirecTV’s 99°, 101° and 103° W satellites, the system can acquire signals from the system’s secondary satellites (61.5° W) and can be used to receive signals from Bell TV in Canada. Power voyagers who plan passages into Latin American and South American waters can install the KVH Tri-Americas LNB.

As with virtually all responses to technical challenges there is more than one way to accomplish the goal, especially when the usual cost trade-off is taken into account. The list price for the HD7 system is about $12,000, a bargain in both dollars and size when compared with previous systems capable of equivalent performance.

Switching between the three

Intellian has created their d-Series systems in response to DirecTV’s move of all HD programming to the Ka satellites. The new d-Series offers two dual band (Ka and Ku) systems, one about the same size as the KVH HD7 with a 27.5-inch diameter, 28.3-inch-high, 44.1-pound dome, the other housed in a remarkably small, 19.7-inch-diameter, 21.2-inch-high, 25.5-pound dome. Both of the d-Series systems include dual Ka, Ku-band LNBs and use Intellian’s Dynamic Beam Tilting and Wide Range Search to minimize the time required to switch from one satellite to another.

Although the Intellian solution cannot provide the simultaneous three-satellite reception available with the KVH HD7, its $6,000 price is about half of that of the KVH HD7. The size and weight advantage of the 19.7-inch-diameter Intellian antenna make it an attractive alternative for many boat owners, especially those who already have a Ku-band system on board and choose to add the Intelllian d-Series to gain access to the HD programs on the Ka satellites. Some owners may elect to install two of the 19.7-inch Intellian d-Series units to permit the widest possible choice of programming. Intellian also offers the option of a dual-band All-Americas LNB that provides coverage for DirecTV, Dish Network or ExpressVu in North America and DirecTV in Central and South America.

The good news is that this immense wealth of TV viewing options will be sufficient to satiate even the most TV-addicted passenger, allowing those who are on the boat to enjoy boating and to do what we like, navigate, enjoy the scenery and the sea.

Contributing editor Chuck Husick is a pilot, flight instructor, sailor, engineer and bicycle rider based in Tierra Verde, Fla.

By Ocean Navigator