“I am no expert in this,” says Big Tom, “just a radio geek who reads whatever papers the NRSC puts out, and the studies that NPR & iBiquity have done.”
He’s no expert, certainly. But he’s also naive if he trusts the NRSC papers. The NRSC isn’t just controlled by the biggest radio companies and the NAB . It’s composed almost entirely of representatives from those entities.
But has he read that latest NPR paper, where they express misgivings about the digital power increase? If “FM IBOC doesn't cause this massive interference that you speak of,” as he claims, then why is NPR suddenly so concerned about the likely effects of a digital power increase?
NPR is too coy to put express their misgivings so bluntly. After all, they’ve invested a lot of their prestige in promoting this folly.
But don’t worry. It isn’t going to happen anyway. Why not? Cost.
An FM signal has constant amplitude, and thus can be amplified through a highly efficient Class C stage, just like radio telegraphy. An “HD FM” signal, in contrast, isn’t and FM signal at all. It uses Coded Orthogonal Frequency-Division Multiplexing (COFDM), with several subcarriers, yielding some fairly large amplitude swings in the signal. And that requires linear amplification. So hybrid transmitters require linear finals, which have much lower efficiency (well below 50 percent, versus 70 percent for Class C finals). They also generate much more heat, adding to air conditioning costs!
Most of the stations that have already gone “HD” bought new “HD” hybrid transmitters to do it. The only alternative was to buy a second, smaller transmitter just for the digital signal and either (a) use a combiner (which wastes a lot of power) to send both signals to the same antenna, or (b) use a separate antenna for the digital signal (which can create coverage problems from interaction between the two antennas).
Now those current “HD” transmitters are still too new to be fully amortized, and they’re supposed to replace them even more expensive, newer ones, that will increase the electric bill even more? Where’s the money coming from? Is the CPB going to give out new grants, twice as large as the first ones?
And it’s even worse for most of the big consolidators. Have you checked Clear Channel’s stock price lately? They and some others (notably Citadel and Cumulus) are on the verge of bankruptcy! So don’t expect any major capital investments.
Now about the comparative sound quality of analog FM and tag-along digital signal:
When it [HD] kicks in, it sounds nice when done right - 101.1 CBS-FM sounds like gangbusters in HD compared to analog, and 97.5 sounds night & day with digital vs analog.
That’s an indictment of those stations’ audio processing for analog, not of analog itself. Analog technology, done right, always sounds better than digital. That’s why some pop recordings are still done on multi-track analog masters and mixed down into digital.
Analog FM is excellent. Unfortunately, our standard analog stereo FM system uses a DSB-SC difference subcarrier. That’ just AM
sans carrier, and it’s relatively noisy. The FCC should have used an FM subcarrier. Major Armstrong could have told them. In fact, he did, in his 1936 paper, “A Method of Reducing Disturbances in Radio Signaling by a System of Frequency Modulation,” in the
Proceedings of the Institute of Radio Engineers, XXIV:5 (May 1936), on page 734. After describing the use of first an AM and then an FM subcarrier, here’s what he said:
This latter method of multiplexing [with an FM subcarrier] has obvious advantages in the reduction of cross modulation between the channels and in the fact that the deviation of the transmitted wave produced by the second channel is constant in extent, an advantage being gained thereby which is somewhat akin to that obtained by frequency, as compared to amplitude, modulation in simplex operation.
The only real problem with stereo analog FM is that, unless the signal is relatively strong, it’s noisy. If we had an all-FM system, with an FM subcarrier for the stereo difference, we’d have good quieting in stereo almost up to the point where the signal becomes too weak for good mono reception. Most of the bad processing we’ve been hearing for the past 30 years (since FM listening surpassed AM) is an attempt to overcome the inevitable background noise that plagues this inferior system (or in some cases, just an attempt to sound louder than the competition). Again, blame the FCC, in this case for choosing the GE-Zenith half-AM system, which was backed by big money, over the all-FM system proposed by Murray Crosby.
But Big Tom sees at least one aspect of this whole mess clearly:
I don't like iBiquity's way of squeezing every last cent from their patents - and the cost of the technology for anyone to start using is astronomical. Even for the college station I program to get the LICENSE (not even the equipment) was around $15,000. Not even taking into account the new transmitter and antenna we would have to buy to start using HD.
Well, Tom, there’s a much better solution. It’s called FMeXtra. It would cost your station only around $15,000 for the hardware. And there’s no licensing fee (the only licensing fee is the one the manufacturer pays Digital Radio Express, Inc., and that’s a one-time fee embedded in the purchase price). The encoder fits in a standard 19-inch rack, and consumes only about as much power as your desktop computer. (Granted, it’s not the answer to multipath, but “HD” won’t be either in most cases if that 10-dB hike goes through. See Reply # 8 above.)
In fact, I’d recommend FMeXtra to all NCE’s. Pubcasters – not all of them, but enough – are the only ones who have tried to provide worthwhile programming on HD-2 and -3 channels. The commercial stations just have a computer playing indifferently programmed junk. (Incidentally, this is true in television, too. Some months ago, I borrowed a converter box, and what do you think I found on WPVI’s “channel 6.2” at 8 on a week night? An “info-mercial” for a quack “colon cleanse” diet nostrum that’s being investigated by the FDA! Is this Disney’s idea of a good use for this technology – in prime time, no less? And you wonder why I’m not eager to buy a new digital TV? I can do quite nicely with a converter box, thank you.)
And now that I’ve found one point of agreement with Tom (about Ibiquity’s rapacious approach to patent licensing), it’s time to end this very long post, before the moderator decides to move this thread to the “HD Radio” message board!
, it will only hasten consumers to trash their radios and get Satellite or other computer forms of music. Get 'em while they're hot! But be prepared to receive good old analog again (only) in a few years as radio gets tired of paying good money to iNiquity for 13 listeners.