Blog Archive

Monday, November 23, 2009

Frozen Pictures and Blue Screens


Over the last few weeks we have started to experience some problems with the delivery of the broadcast stations from Nashville and Louisville. This trouble manifests itself as a frozen image or blank screen, and it is one that we predicted long ago as the FCC mandated that broadcast stations change from analog to digital. Back in 2006 our newsletter carried full details of this matter and, since our prediction is coming true and some folks are concerned, I am reprinting that 2006 article below:

With apologies to Professor Harold Hill and everyone associated with The Music Man. . . Well, we got trouble my friend, right here in Broadband City. . .I say trouble with a capital “T” and that rhymes with “D” and that stands for digital broadcast signals.

That’s right. Digital broadcast is trouble. It might not be as bad as the game of pool was in River City, but it certainly gets us some calls and occasional criticism from our customers. These calls are because of signal interruptions on cable channels carrying broadcast stations in Louisville and Nashville. We did not cause these problems and solutions are particularly vexing and expensive. While we think we have explained this matter ad nauseum in the past, we keep getting questions about it so we are going to try once again. Here goes.

If you have been watching a program which originates at a broadcast station in Louisville or Nashville, and the picture freezes, pixilates (falls apart into something resembling puzzle pieces), has interruptions to the sound, has episodes where people’s lips and the sound are not in synch, or the picture just goes away and is replaced by a blue screen with the words “no signal”, you suffer from a malady much worse than Restless Leg Syndrome. You are experiencing analog-to-digital-conversion-syndrome (ADCS). However, neither Merck nor Pfizer has a pill, of any color, which will cure ADCS. It is one of the great failures of the American pharmaceutical industry.

To better understand this disease, we must first make sure everyone understands just what “analog” and “digital” mean. Up until about three years ago all transmission of television signals from stations that broadcast to people with an antennae, as well as to cable operators with a very big antenna, was done via analog transmission. Analog simply means real, measurable, or continuously variable. Hmmm, that might not be clear enough. How about this? If you still have a watch that has a bunch of little springs and cogs and gears in it that rotate and whir about resulting
in a big hand and a little hand telling you what time it is, you have an analog watch. It gives you the time by knowing how far to move those hands in a minute. Similarly, analog broadcast signals carried moving pictures by constantly modulating certain frequencies that were sent out over the airwaves to be picked up by an antenna and tuned by a television set. Okay? Analog was a great way to send out television signals. While never perfect, analog signals carried for a long way and that helped places like Glasgow to get news and programming from far away places like Nashville
and Louisville. As weather or other interference occurred in the analog world, the signal would degrade some, our customers might have seen a bit more noise in the picture, but it would still be watchable. As you can see in the graphic, Glasgow was never in the “good” range of analog transmission from those cities, but we made it work pretty well because analog signals are very resilient and tunable over a wide range of power levels. But, as technology and greed marched along together over the last several years, other companies like cell phone providers and other wireless systems began to lobby Congress and the FCC to force the broadcasters to use new digital broadcast technology. In theory this new technology is far superior and uses a lot less of
the broadcast spectrum (that means a lot of the old analog frequencies would be available for more cell phones and other things with buttons, screens and irritating noises that keep you from being able to enjoy any peace and quiet anywhere). Therefore, as is often the case, while you were not watching Congress and the FCC agreed with the lobbyists and decided that all television broadcasters should abandon the old analog technology and replace it with new-fangled digital
transmission technology. I think maybe they all got a free cell phone for making this decision.

Earlier we described analog as being measurable or real, but digital is quite different. Let’s go back to the watches. If your watch is not analog it is digital. With a digital watch there are no moving parts - no wheels, springs, or gears. A digital watch just has a little processor in it running a program. The program counts little electronic pulses and converts that calculation into lighting up some little diodes to display something like “1:27". Digital television transmission is like that as well. It has no “moving parts”. Instead, it sends you a staggering flow of 0's and 1's that our receiver
here interprets, and performs calculations on. Instead of telling a bunch of LED’s to display “1:27", it converts the calculations into near perfect pictures and colors that appear on your television set and allow you to see that those Desperate Housewives have quite the colorful life. Now you know all there is to know about analog and digital transmission. Don’t you feel technical now?

Now let’s look again to the graphic because there is one more thing to know. Digital signals do not carry as far as analog signals. In addition, digital signal does not slowly deteriorate and remain watchable as the signal gets weaker. Since the digital signal is not “real” but only a long series of binary numbers that need to be computed by our receiver, when some of those numbers come up missing because of weak signal, the picture does not compute so it just falls apart and stops. Depending on your television, this results in a frozen picture, a puzzle mess, or a blue screen. The
power levels and the frequencies allotted for digital transmission have one clear result; they were never intended to carry more than about 50 miles! As you can see on the graphic, we are outside of the intended range of digital transmission from both Louisville and Nashville. This is not our fault because we did not pick where Glasgow is located. Further, we did not pick the digital transmission standards. Very “smart” people in Washington D.C. did that.

Okay, now you know about analog and digital and you have a map to show that we are in the digital hinterlands. You also know that none of this is our fault. All that is left for us to discuss is the fact that you expect us to fix it anyway, right? Well we have been working on that.

Like everything else, this matter comes down to money. There are ways to improve upon this situation. We can install an antenna closer to the broadcast stations and bring the signal to Glasgow via fiber. We can also purchase the signals from certain satellite vendors for delivery
to our receiving dish. But most of these solutions spend tons of money for very little additional signal improvement. With this economy, that just seems unwise.

That is how we explained it nearly four years ago. Since then we have done a ton of expensive work improving our antennae and getting some signals delivered via fiber. Also, retransmission consent changes in 2008 changed to menu of stations we are trying to deliver. We made decisions based upon what stations we thought we could deliver and the capacity of our antennae systems to deliver them with reliability. Most of those decisions have been good. The slate of Louisville and Nashville stations we are able to deliver in High Definition is long and the troubles have been very few. BUT, none of this is perfect. We can accept 98% reliability for stations like WHAS and WSMV or we can choose to drop them entirely if they are not 100% perfect all of the time. We would be interested in hearing from our customers if they feel we should react to this dilemma differently.

3 comments:

jrb8185 said...

but that is not the same issue as the sporadic cable and internet outages we experienced throughout this past weekend, right? I looked for tweets (I follow EPB on Twitter) or other messages/alerts indciating what the problem was or how long the outages would continue, but couldn't find anything.

Billy Ray said...

No, it had nothing to do with that. I suspect you may live in the Longhunter's Trail area. We have had a difficult to locate problem with something out there that has given us trouble for a couple of weeks. We should have been tweeting about that one. Sorry. We will do better!

jrb8185 said...

Yes, we live on Rebecca Lane. Thanks for the response.

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