Perhaps you are very happy with the antenna you already have, but would consider replacing your current analog transmitter with a combined-amplifier type. Fortunately a lot of transmitter development has gone on over the last five years and buying this type of transmitter is easier now than it was way back when.

Nautel offers an extensive line of all solid-state combined-amplifier style transmitters as the NV Series. This line extends from the NV3.5, with an analog power rating of 2,700W of analog at the -14dBc IBOC level, up through the NV80, which will make 57,600W of analog in the -14dBc mode. The Nautel Power Boost is a peak-to-average-power reduction technique that Nautel estimates will effectively boost the analog power capability of the NV Series transmitters by about 1.3dB.

Nautel offers an Excel file tool to determine if a transmitter is capable of delivering the increased digital power, and what steps need to be taken to accommodate the increase.

Harris has been busy working on its IBOC transmission technology as well. It offers three lines: the ZX series (500W up to 5kW); the Z/HD+ series (4kW up to 32kW); and the vacuum-tube series that includes the HT/HD+ and HPX20 through HPX 80. Harris is also working on its version of peak-to-average power reduction, and will introduce it at the 2010 NAB Show. Harris expects to gain about 25 percent more analog power from its combined amplifier types when this algorithm is fully implemented.

At the time of this writing, Broadcast Electronics is in the process of evaluating and optimizing its transmitter line for proposed IBOC power increase.

Because the proposed IBOC power increase hasn't yet been approved by the FCC, it may be a little early to budget for transmission facility upgrades — but at the very least you should be in the planning stage. Increasing IBOC power by even four-fold is no trivial matter, and it could affect the entire infrastructure of your transmission facility. If you believe that terrestrial broadcasting has a continuing future, as I do, then now is the time to plan for it.

Irwin is transmission systems supervisor for Clear Channel NYC and chief engineer of WKTU, New York. Contact him at doug@dougirwin.net.