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Update on Transmitters
Continental Electronics has maintained its familiar line of high-power FM transmitters, the 816R series. Power levels range from 11kW to 21.5kW (using the 816R-2C) up to 40kW (the 816R-7C). A single tube is deployed as the final amplifier (4CX15000A, 4CX20000E or 4CX25000C depending on the power level). All of the series are self-contained, except the 816R-7C, which uses a separate power supply cabinet and external harmonic filter.
The 816R-HDR (HD-ready) is a high-power combined amplifier for IBOC applications. It can be purchased as an FM-only transmitter, while planning to add the IBOC components (the Exgine-enabled 802Ex digital FM exciter, along with an exporter) later. Continental's D816HD series transmitters range in combined TPO from 18kW to 56kW at HD power levels of -20dBc to -10dBc. These combined transmitters use only one tube each, the final power amplifier tube. The D816HD Series Transmitters are also completely self-contained, including the harmonic filter. (The 70kW has two high-voltage rectifiers and plate transformers located in two separate chassis.) D816HD transmitter systems work with Continental's 802Ex digital FM/HD Radio exciter to provide forward looking fully adaptive pre-correction, system and digital performance monitoring and on-channel spectral analysis.
To the low side
LPFM stations are those authorized to operate as noncommercial educational stations, with an ERP of 100W or less. The maximum facility is 100W ERP with an antenna HAAT of 30 meters. The approximate service range (60dBu) of an LPFM is 3.5 miles in radius. LPFM stations are not protected from interference that may be received from other classes of FM stations.
During the last filing window (which was held between Oct. 15 and Nov. 14, 2013) 2,800 applications were received by the Commission; as of the time of this writing, about 1,000 LPFM CPs have been granted.
If you happen to be holding one of the aforementioned CPs, you might wonder what to do next. To create a maximum facility for an LPFM, consider this: a single-bay, circularly polarized antenna, with about 200W making it to the antenna input port. There are quite a few options in transmitters that are capable of 300W.
BW Broadcast has come on strong in the last half-dozen years. It offers the TX300 V2, a stand-alone transmitter capable of 300W. One box houses the exciter, power supply, power amplifier, a stereo generator and audio processor (basically lifted right from the design of the BW DSPX miniFM). Audio inputs are balanced XLR. The internal audio processor can be bypassed if an external unit will be used to drive the BNC composite input of the transmitter. The RF output is on a type-N female. The ac input can accept between 85Vac and 260Vac, which yields some flexibility with the installation. Remote control can be done via RS-232, requiring a computer at the transmitter site for remote access; or, via its new software, Ethernet access to the transmitter can be had via its embedded Web interface. In either case the transmitter site will need network access.
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