Brand loyalty plays a big part in transmitter purchases. Experiences play a major role in the development of loyalty or its antithesis.
You should never habitually ignore a brand, especially before a major purchase. Models are introduced regularly with new features, some of which could change your attitude, should you learn about them.
That�s one reason why a trip to the NAB or Radio Show is so useful. But you can learn by speaking with colleagues about what they are using. If a your friends raves about �the new box,� it makes sense to check it out.
Let�s take a sampling of what is available now.
Broadcast Electronics offers transmitters in four power ranges. The largest single-tube transmitter line is the T-series; the range is between 20 and 40 kW. The S-series offers a completely solid-state solution in the 4 to 20 kW range; the solid-state C-series range is from 500 W to 5 kW.
The STX-10 is the newest solid-state FM transmitter in BE�s transmitter line. It requires 22 RU of vertical space in a standard rack (30 inches deep) with 70 percent AC-to-RF efficiency. STX-10 makes use of hot-pluggable power amplifier modules and power supply modules. If you are planning to transmit HD radio, you would then equip the STX-10 with a STXe 500 exciter. While considering remote access, keep in mind that the STX 10 can be accessed from any PC, tablet or smartphone and is also SNMP V2 and V3 compatible. STX-10 can also be used in an N+1 system, or in a single frequency network, due to a delay feature in the exciter.
BE produces two lines of AM transmitters, as well: the A series (500 W to 10 kW) and the E series, at 2.5 or 5 kW.
Continental Electronics continues to offer the 816R line of FM transmitters and the 816-HD and 816-HDR lines (HDR meaning �HD-ready�). The 816R line covers the power range of 11 to 40 kW, using the same three-bay design for the last 30 years, with the 4CX15000A, the 4CX20000E or the 4CX25000C (depending upon power level) driven by the solid-state IPA.
The 816HD family of transmitters is based on three different analog FM + HD power levels: the 816HD-20 for power up to 20 kW; the 816HD-25 up to 25 kW of power, and finally, the liquid-cooled 816HD-28L for applications up to 30 kW of analog power.
Nautel�s newest transmitter line for FM is the GV series. It�s completely solid-state and of modular design, so that failures in one (or more) PA modules, or power supply modules, or the user interface itself, will not take the transmitter completely off-the-air. All GV Series transmitters include Nautel�s Advanced User Interface with 17-inch touch screen monitor and IP access; so whether you are in front of the transmitter or at some other location, 100 percent of the AUI is available to help you manage the transmitter. With the AUI, you can configure and then monitor the following:
� All the individual preset configurations (frequency, power level, HD power program audio input)
� Dynamic RDS scrolling
� New oscilloscope instrumentation
� Unique MER instrumentation
� RF and audio spectrum analyzers
� Monitoring and control to the sub-module level
� Logging of all events
� SNMP support
� Email notifications
The real-time measurement of modulation error ratio provides the ability to diagnose issues such as interference with the MP3 carriers near the analog signal due to FM analog signal over-modulation.
The chart below shows analog and analog + HD power for the GV line:
Nautel has a line of AM transmitters as well, known as the NX series, at the 5, 10, 25 and 50 kW levels.
If you read the �Justify It� article, then the following will be especially pertinent:
These figures represent overall efficiency (AC-to-RF) but don�t include modulation. When you make your comparison chart, try to make it as close to �apples vs. apples� as you can, to be fair.
The NX series also includes the Nautel AUI, meaning that all local control and configuration can be done from anywhere you have IP access.
GatesAir has an extensive line of FM transmitters. Let�s take a look at the Flexiva line. It�s scalable, for power levels between 5 kW and 80 kW. A 10 kW version needs 16-RU of vertical space in a rack. A common 1800 W power amplifier module is used as a PA, or as an IPA. PA modules and power supply modules are hot swappable.
Some of the Flexiva�s other important features are as follows:
� Continuously variable speed fans optimize cooling; redundant internal cooling fans draw air from front to rear with ducted air options available
� Digital Ready: FM, FM + HD Radio, HD Radio only
� Maintains power up to 1.5:1 VSWR. Proportional VSWR fold-back for safe operation at reduced power into marginal loads (icy antenna, etc.)
� Global control and monitoring via IP; the remote graphical user interface works with any PC, tablet or smartphone
� Full SNMP network control and monitoring support
� Diagnostics and setup via an easy-to-use front-panel control
� N+1, Dual Transmitter and Main/Alternate and with automatic switching capability
It should also be noted that GatesAir introduced the Flexiva FLX range of liquid-cooled transmitters for FM and digital broadcasters. The design incorporates a heat-to-liquid transfer that removes heat from the RF plant �without excessive air conditioning, helping broadcasters cut monthly utility costs and establish a greener plant. The transfer itself cools the air in the RF plant, moving transmitter heat to the outside via a liquid-to-air heat exchanger with redundant fan systems,� according to GatesAir. Further: �To obtain maximum efficiency, the liquid-cooled design, in most installations, integrates low-noise pump modules within the transmitter to further reduce its already compact footprint. Two fully redundant cooling pumps operate in a closed-loop design, with auto-changeover capability in the event of a failure to ensure proper and constant transmitter cooling.�
GatesAir continues to offer AM transmitters. The DX line is still available, along with the 3DX series.
Take a look at the efficiency chart on the following page.
Most of the VHF FM transmitters mentioned to this point can be operated in a N+1 fashion, meaning that, when connected to a broadband VHF antenna, they can have their operating frequencies changed �on-the-fly� and thus become backup transmitters for a cluster of FM stations.
Smaller, lower power transmitters to consider for N+1 operation could be:
� Nautel VS-series
� GatesAir FAX series
� Broadcast Electronics STXe series
In the low-power domain we have other manufacturers to consider. For example, BEXT offers the XL series (1k and 2 kW versions in 2-RU of vertical space).
Its salient features include:
� Fast access to settings and all readings from front panel via menu display and via IP or USB
� Telemetry and remote control connections
� User manual and tech documentation accessible from front USB port even when unit is not powered
� User programmability allowing for N+1 backup to multiple stations
� Proportional Auto-Foldback of output power in the event of excessive VSWR
� Adjustable power output from 0 W to full power, with soft-start control
� Includes low pass/harmonic filter and meets or exceeds all FCC and CCIR requirements
� Optional built-in, stereo generator w/ fast audio clipper
Another option for lower power would be the Crown E-250 (manufactured by Ecreso). The power level might seem a little low, but even 250 W is much better than being off the air.�
Some of the E-250�s features are:
��� 2-RU vertical space required
��� Built-in stereo generator that can use AES or analog inputs
��� Silence detection and failover to alternate audio input
��� Dynamic RDS encoder
��� Full-set of GPIO
��� Remote access via IP, using Web browser of SNMP
This was not meant to be a comprehensive list of every transmitter out there, but I hope you�ve gotten some ideas. I hope you undertake some� research of your own.