Skip to main content

Broadcasters Mull Low-power Options


With the FCC's move last November to relax the timetable for full DTV maximization and replication, vendors say business is brisk for low-power DTV transmitters.

The stations cited a variety of issues preventing them from broadcasting digitally at full power, including ongoing band-clearing negotiations for UHF slots, tower site and zoning problems and logistical problems such as delays in transmitter delivery and installation.

But the biggest issue is money - the cost of buying and operating a full-power transmitter while the DTV audience is too small to generate any return on investment. Low-power transmitters get DTV stations on the air quickly and cost-effectively - covering at least their city of license - until they are ready to install their full-power DTV transmitters.


Last year, many of Harris' customers began asking for a low-power transmitter to help manage costs and delay full DTV implementation.

"We responded with the Ranger, our first low-power DTV transmitter, offering stations considerable savings on the cost of electrical power, space and installation," says David Glidden, director of TV Transmission Products for Harris in Mason, Ohio.

Glidden says Ranger can save broadcasters $50,000 to $75,000 per year in electricity compared to operating a 60 kW IOT transmitter. That can quickly defray the capital cost. And with a fully configured Ranger system (including encoder and antenna), available for under $150,000, stations can buy time until they resolve problems such as tower site location or can justify the bigger ($500,000 to $1 million) investment in a full-power transmitter system when their DTV outlook improves or the FCC forces a broader build-out.

The solid-state Ranger occupies a single 19-inch rack cabinet that can often be installed right at the main studio facilities. And, it can be upgraded from the 500 W version to 1000 W. For stations that later want to increase their ERP (Effective Radiated Power), 80 percent of the Ranger's parts - the CD1A exciter, power amps, and power supply, for example - can be reused in the full-power transmitter. Only the Ranger's control panel and filter mask would not be reusable, because they are scaled for lower-power operation.

As for the best strategy for stations going forward, Glidden says, "That depends upon each station's unique situation - their power needs, marketing plans, and budgets. While many stations have justified going full-power from day one, some stations are finding that low-power DTV transmission can be a beneficial strategy until they must go full power."


The decision whether go for a low- power DTV transmitter is a financial decision, says Joe Turbolski, director of marketing for Thales Broadcast and Multimedia in Mountaintop, Pa.

"For some DTV broadcasters, it's important to get on the air quickly and inexpensively, covering their Grade A contour, including their local cable head-ends," he says. "But their primary goal is to minimize their up-front capital costs while the penetration of DTV receivers is still small."

For these broadcasters, Thales offers the Affinity, which consists of solid-state LDMOS amplifiers in 50, 100, 200, 500, and 1000 W power levels. Affinity, which uses Thales' ADAPT exciter, can also be configured with a "Starter Pak" that includes the SD (or an HD) encoder, Amber remultiplexer and static PSIP generator in the same rack as the transmitter for a complete transmitter solution "in a box."

"But others prefer to invest in upgradeable low-power transmitters designed to mimic closely what their full-power requirements will be. In this case, they pay a little more upfront, because things like filtering systems would be sized for high power. But then when they decide to go full power, the upgrade is much, much easier, and all of their initial investment is protected," adds Turbolski.

For this group, Thales offers the BeachHead, a fully upgradeable transmitter with solid-state, bipolar amplifiers in 400 W or 800 W power levels. Everything in the BeachHead is reusable, including the control system, eliminating the need to retrain engineering personnel. It can be upgraded to 100 kW by adding the appropriate number of high-power IOT amplifiers.

Another reusable low-power solution from Thales is the Ultimate Compact solid-state transmitter, with LDMOS amplifiers, in power levels from 400 W to 3200 W. It can be upgraded up to 20 kW by adding additional solid-state amplifier cabinets. Available in air- or liquid-cooled models, the Ultimate Compact can also be migrated from UHF to VHF for operators wanting to retain their original channel after the DTV switchover.


"One of the biggest issues related to buying new DTV transmitters is the negative impact on the station's cash flow," says Mark Polovick, national sales manager for Ai (formerly Acrodyne) outside Baltimore. "Cash flow is critical because the station's value at sale - and its ability to borrow money - is tied to the cash flow, or amount of revenue remaining after all the bills are paid. If, by turning on a DTV transmitter, the station increases utility expenses without generating additional revenue, that would result in a negative impact on cash flow that would diminish the station's value.

"One strategy that broadcasters are employing to preserve their cash flow is to upgrade their older NTSC transmitters to more energy-efficient models. The itilities savings can help offset the cost of DTV transmitter operation, and minimize the negative impact on cash flow," he said.

Traditionally a station's value is determined by multiplying its cash flow by a factor - say, 10, 12 or 15 - rather than by considering the value of capital assets such as transmitters. So, if utility costs of $15,000 per month can be cut in half by upgrading the NTSC transmitter, the $90,000 annual savings is worth about a million dollars to the station.

"If these savings offset the negative impact of the DTV transmitter's operating costs on cash flow, the station's value isn't diminished by DTV compliance," said Polovick.

A low-power transmitter specialist, Ai has two solutions for the DTV market. As the exclusive U.S. representative for Rohde & Schwartz, Ai offers that company's affordable, compact, modular, low-power solid-state transmitters, scalable (with a changeout to an IOT tube and other components) to high-power 50 kW to 70 kW.

Ai also offers its own Convertible Series, which is essentially its high-power Quantum IOT tube minus the IOT tube. It produces 500 W to 1000 W of power. The Convertible can be upgraded to a Quantum full-power transmitter by adding the IOT tube and associated power amplifiers and cooling elements.


Since every station's situation is unique, Axcera (formerly ADC-ITS) offers several cost-effective options so broadcasters can select the best possible path to DTV. One is the DT-Value, a low-power transmitter package (including the encoder, monitoring equipment and Axcera's DT-800A Series low-power transmitter), which ranges from 50 W to 5 kW. Up to 500 W, the system fits in one rack, including the output filters for the transmitter.

"The benefit of such a unit is not to upgrade to a high-power transmitter, but rather to get on the air quickly and capitalize on the initial savings offered by taking this route," says Richard Schwartz, director of marketing for Axcera in Lawrence, Pa.

"Additionally, by not locking customers into a product long-term, they have the flexibility to choose the latest technology available when they do select their high-power transmitter," he says. "Once the full-power unit is installed, the low-power DTV transmitter can be used as a backup transmitter, converted for NTSC operation, or even reconfigured as a translator or on-channel booster."

For those who prefer an upgradeable system, Axcera offers the DT Gateway, which consists of the driver system from a high-power Visionary DT IOT transmitter for 150 W to 350 W output. "With the addition of IOT amplifiers, it can be upgraded to a Visionary DT, capable of up to 180 kW, protecting the customer's investment," adds Schwartz. Axcera also offers the Innovator, a modular solid-state system, which can be purchased at low power and upgraded to high power (5 kW to 20 kW) by adding PA modules.


At KTech Telecommunications Inc. in Chatsworth, Calif., inquiries for low-power DTV transmitters were particularly strong in January and February from stations that filed to extend the May 1 deadline. But then inquiries tapered off.

"Broadcasters that hadn't yet made a decision by March opted to wait for NAB to see if any new products or lower-priced options would emerge," says James Y. Jun, KTech's director of marketing.

KTech's XMT-100 solid-state DTV transmitter includes a Harmonic SD encoder, single-channel PSIP generator, 8-VSB modulator with automatic adaptive pre-corrector, RF upconverter, amplifier and DTV mask band-pass filter in a 19-inch rack for about $80,000 at 100 W. The system is scalable from 100 W to 3 kW, and is upgradeable to full power.

"While the first extension was automatic, those stations needing to file a second extension next November will have to give the FCC more specific explanations as to why they haven't gotten their DTV transmitters up and running," says Jun. "Since it can take anywhere from three to five months to order, ship, install and test new transmitters, these stations really must place an order very soon to make their November deadline."