Matt Sanderford, Jr.
ALVARDO, TEXAS—As an engineering services and consulting company, Marsand has been dedicated to meeting the technical needs of broadcasters for more than 30 years. Our extensive experience in the industry includes the planning, installation and commissioning of television transmitters.
Our deep understanding of transmitter technologies and regular conversations with broadcasters give us a unique perspective on what stations need when they’re considering a new transmitter. While the necessary capital investment remains a factor in the decision, operational costs—maintenance requirements, and energy—are increasingly important considerations and for full-power operations, can be deciding factors in system selection.
One of the newer transmitters addressing the need for reduced operating expenses is the Rohde & Schwarz THU9.
We’ve been involved in a number of THU9 installations and know first-hand that the system is well-engineered and suitable for full-power broadcasters looking to take advantage of all that solid-state technology has to offer, including increased reliability and simplified and reduced maintenance, while matching the performance and efficiency of an IOT-based transmitter.
One of our installations was for a network- owned station in Las Vegas. This particular system was in a two-cabinet configuration and used Doherty technology amplification for high-efficiency performance. This transmitter is easily configurable to a customer’s requirements, as it supports up to 12 amplifier modules per cabinet, and when completely populated, produces 13.5 kW ATSC per cabinet in high-efficiency mode.
AN EASY INSTALLATION
This THU9 was being installed to replace an IOT transmitter and we were fortunate that the channel filter from the earlier installation still in place and serviceable, so installing the new RTHU9 was really a snap.
After verifying that the filter’s performance was still within factory specifications we took measurements on the antenna and transmission line system. Then it was time to connect up the transmission and power supply and supply input signals. Once this was done we were ready to power up the new transmitter.
We double checked everything and applied power. As expected, the new unit powered up as smooth as silk and we were we making RF. To verify the THU9’s performance, we connected a Rohde & Schwarz ETL TV analyzer and within a very short time we were able to verify modulation error ration of 42 dB. The equalization in the ETL was set to off for the duration of our performance measurements.
Other than making some precorrection adjustments via the transmitter’s LCD touch panel interface, no other adjustments were required during the setup and checkout.
LESS MONEY FOR THE POWER COMPANY TOO
As a final step, we calculated the unit’s efficiency. Measurements were taken across each circuit, which included the cooling system associated with each cabinet. Based on our experience with the R&S THU9 transmitter line, we were not surprised when total system efficiency calculated out to be 42 percent.
We’ve found the THU9 to be a solidly engineered system which provides maximum signal quality and high efficiency. It certainly goes a long way to eliminating maintenance hassles associated with tube units and has the advantage of substantial energy cost reductions provided by Doherty-enabled amplifiers.
Matt Sanderford, Jr., P.E., is the president of Marsand, Inc. He may be contacted attvcowboy@marsand.com.
For additional information, contact Rohde & Schwarz at 888-837-8772 or visitwww.rohde-schwarz.us.
