Michael Grotticelli /
11.13.2009
Originally featured on BroadcastEngineering.com
Harris HD-STAR helps test signal integrity during live sports events

Sometimes the smallest technology solutions carry the most value for live event production.

One of the biggest challenges for freelance video engineer and RF technician Jason Shank when setting up live video feeds for major golf tournaments and other live events for major sports networks and other clients is making sure the signals from the wireless camera transmitters on-site are being received at the production truck on-site and that there’s no signal degradation or interference to get in the way.

This task usually required Shank to use a camera or other HD source device to test signal strength and continuity, although tying up a camera for this purpose always seemed counter-productive and a waste of a piece of gear that could be used for other purposes.

Working alongside crews from production company Total RF, which provides the RF microwave links at many sports events (usually between five and 10 RF links depending on the size of the golf course or venue), Shank recently used the Harris (Videotek) HD-STAR, a handheld HD signal test generator and monitoring device, for the President’s Cup last month, in San Francisco, for the Women’s Open in Bethlehem, PA, in July and the Celebrity Golf Tournament in Tahoe, UT, also in July.

“In the digital world, a test signal output that actually has something moving on it is imperative for testing signals as you move around a golf course or other large venue,” Shank said. “That’s the only way to get an accurate testing of the RF path. The camera was the best source we had to test with before we got the HD-STAR device, because we could move around the course with it. Now, instead of having to borrow a $100,000 camera from the production company, we’re taking a $5,000 piece of test gear. It makes a lot of practical sense.”

Similar to most live sports productions, each event included multiple mobile production units on-site. The broadcast compound also included editing and graphics trailers as well as hospitality and office units. The trailers were interconnected to route monitoring signals and feeds to and from the course. The core of the production facility was a double-wide mobile unit that housed production, audio, video control, graphics, tape/server/replay, engineering and editing; a mobile unit used for transmission (satellite backhaul to the networks); and a RF/fiber interface trailer. The RF/fiber interface trailer served as the central location where all of the signals from the course passed though on their way to the production control area.

At each golf event, miles of fiber-optic cabling is run to and from the course. The fibers carry the camera signal back to the broadcast compound and carry signals from RF receive sites to the monitors that the talent uses in the announcers’ tower. A number of cameras were used handheld or positioned on special vehicles called “rats,” which move cameras around the golf course. To simplify the installation and cabling requirements, they use wireless RF cameras to add to the mobility. The RF cameras have receive sites scattered around the course, which in turn relay the signal back to the compound via a video cable or fiber-optic path. The fiber is then converted to coaxial cable for distribution to the mobile production units within the compound.

For a typical setup, Shank takes advantage of the HD-STAR’s signal generator and its “moving bars,” which represent a moving signal that can be added to the RF transmitter.

“Moving bars is best described as bars with motion,” Shank said. “The point of replacing a camera is that the bar signal has motion in it as does an actual image from a camera. An RF receiver will tend to freeze the last image decoded, similar to a frame sync, when the RF signal is disrupted, which could be due to many reasons such as weakness, overloading or interference.”

This allows him to walk around the golf course with a mobile handheld device and freely check and verify the RF video path. This is an improvement over using a standard set of nonmoving bars, which doesn’t have the capability to look for digital freeze-frames and other digital break-ups. Adding the HD-STAR to the setup process eliminated the need to move RF cameras around the course during the test process, Shank said.

As far as testing the RF transmission paths from the receive sites, Shank said the moving test-signal feature on the HD-STAR was very handy. One of the faults of testing an RF pattern is that it is always connected to a frame synchronizer, and if the signal is lost, the frame sync generates a freeze of the last good signal by design. The problem is that from a signal-path test point of view, the signal may be gone, and no one would know because a “normal” test signal appears to be frozen. The HD-STAR’s motion test signal helps verify these paths, because the test signal is not frozen. Coupled with the fact that the unit runs on batteries, it is very useful in testing the receivers on the golf course.

In addition, each golf event includes a small interview area used for preproduction interviews that eventually get edited into the program. Shank uses the HD-STAR to verify the HD signals in various formats (1080i or 720p) from the cameras, that the frame rates are correct and that they match each other in color and brightness. The HD-STAR features an auto-detect mode that automatically tells the user what signal format (and frame rate) it is receiving. This helps Shank set up the right source to the right format and ensure that all gear is in sync. The HD-STAR also features signal strength detection, which allows him to react quickly and adjust the setting in the source equipment, and then verify through the HD-STAR that the right signal is being provided at the source.

“Because we're often working with different signal types on the same production, it’s very helpful to have a device that tells me what signal is coming from what source,” Shank said. “It saves me a lot of time and takes a lot of the guess work out of the equation.”

Shank said the HD-STAR’s eight hours of battery operation really comes in handy during “long days.” The interview area, like other production facilities, may have a return path to the compound. This means the area can be used during the event and video stored on a server in the mobile units. In this case, he uses the HD-STAR to send a test signal back to the production truck to verify the integrity of a particular cable run.



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