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HD bugs

In your January editorial, you forgot to mention that local stations power down their digital transmitter for a day or two (with no explanation) for maintenance or to let someone else install their digital antenna, etc. Also, there is either a poor guide to HD programming, or none at all, especially on the PBS station in Orlando, FL, which is running the PBS high-def feed part-time, separate from their analog feed (when they don't have their hand out for money).
Charles E. Thompson

Audio rates, frequency change


This one may be foolish, but I've wondered if movies are slowed down for viewing on TV, since the NTSC field rate is 59.94 per second. I calculate that this adds a few seconds per hour of material. I know it's only 0.1 of one percent, but would this be enough to change, for example, the pitch of music? Would someone with perfect pitch notice the difference? Or is some other compensation made when telecining movies to video?

Another question, I understand that they changed the scan rate from 15750 to 15734.25 to make the 227th and 228th harmonics of this frequency just straddle the color subcarrier at 3.579545MHz. But what were the reasons for locating the color subcarrier at that frequency, rather than one that would have allowed the horizontal scan frequency to stay as it was?
Jay Sclar
Wyckoff, NJ

Michael Robin responds:

Concerning the audio pitch change, I don't think any normal person would notice or be annoyed by it!

Concerning the location of the chrominance subcarrier, its frequency must be a multiple of half the horizontal scanning frequency to achieve frequency division multiplexing with the luminance spectrum. So keeping the original horizontal scanning frequency unchanged, the audio carrier frequency would have to be changed. This was entirely possible and would have worked quite well, but the FCC objected to this approach and now we are stuck with the consequences. This was one of the “wise” FCC decisions.


Dear Brad,

I was perplexed by your editorial in the November 2003 issue. Since I learned about Broadcast Engineering in the mid-60s, I have looked to this magazine for industry news and insight into new technologies, and felt it was geared to "in-the-trenches" engineers. However, I read you to be saying that there is no more use for staff engineers. Maybe not even a chief engineer in the long haul. And maybe that is inevitable.

In my early days, at the local radio station that I hung around until they put me to work, the chief engineer talked about how the management sector desired to get to a point where they could just call the local radio and TV service shop (we still had those in the 60s) when something went wrong. I thought “never,” but his prophesy has come true. Maybe it isn't the local service shop getting the business, but the contract engineers, corporate engineers and, as you suggest, the specialist companies.

What perplexed me was that, rather than lamenting the coming end of staff engineers, you seem to be encouraging it. At that point, I feel the need for Broadcast Engineering will cease. The base of readers will be so small that advertisers will find other means to influence those purchasing equipment and services.
Mike Daniels

Brad Dick, editorial director, responds:


I recall the early days of TV automation. My fellow engineers complained bitterly about the use of the new technology. But you know what? It came anyway, and it made stations more efficient. The result was that those engineers who saw the technological change as an opportunity, rather than a threat, got to keep their jobs.

Change is uncomfortable, sometimes in bitter ways. And complaining won't change the inevitable. The desire for increased efficiency drives perhaps most business decisions in some way. Today, that desire for improved efficiency, better workflow if you prefer, can be a factor in 90 percent of the equipment-buying decisions. We can either embrace change or be run over by it. When is the last time you saw a “TV repair shop”?