A recent article about the rollout of HD Radio in FMQB by Paul Marszalek points out some of the good things, and some big pitfalls that may be ahead for terrestrial radio in the USA.
Although IBOC radio was not the best choice for terrestrial broadcasters, with its exclusive focus on retaining the entitlement of incumbent broadcasters to the exclusion of all other considerations. Unfortunately, that choice required squeezing of ten pounds of s**It into a five pound bag.
We can look back as much as we want, but we are where we are. There was no concept of how streaming, podcasts, 802.11 radio and cellphone stations would dilute the terrestrial franchise at that time.
We need to understand that IBOC hybrid HD Radio is a TRANSITIONAL technology. In ten years, if we play our cards right, there will be no analog radio, and we can have THREE programs on an FM license and one CD quality stereo or one “FM quality†a number of voice quality programs on an AM license. All this can be achieved with NO adjacent channel interference.
Lets now focus on how broadcasters can go from where we are into the future with a good enduring business model. First, we need to listen to folks like Russ Oasis and his recent “Open Letter†to broadcasters about marketing of the secondary FM channels.
The next thing we need to focus on is how to get HD radios into the hands of the public – quickly and in high enough numbers to be able to turn off our antiquated analog signals, and transmit in glorious full digital clarity!
Digital only HD has all the “legs†that broadcasters wish for:
AM broadcasters will be free from summer static crashes, will have CD quality, and gigantic interference free servce areas. (A class A medium wave station will be equivalent to an XM channel at night)
As an example, the Ibiquity experimental station, in Frederick, MD on 1670 kHz with 10 kW when switched to digital only mode was carried with CD quality and NO dropouts all the way to Harrisburg, PA – over 100 km. That is down to less than the 0.1 mV/m contour. The analog signal gets scratchy at 40 kM. That is more than SIX TIMES the service area.
Now, obviously 1670 is a pretty clear channel, but the digital only signal has a more generous protection ratio (the difference that is needed between two stations to avoid interference) as a result, IBOC stations will have much smaller “no mans land†between the locations where one staton stops serving and the next one can pick up.
FM broadcasters presently only gain in signal quality when a strong signal is received. The digital signal is transmitted at such a low power that it travels no better than the analog signal. When stations convert to full digital – then the building penetration, the complete immunity from multipath and larger service areas come into play (for the same reason as full digital medium wave – better protection ratio from interference)
I think we need to avoid complaining about where we might have been, had other choices been taken. We are here – Now focus on a path where terrestrial broadcasting needs to go to maintain its role in American society.