Plugged In: the DTV Switch

Come together...

JH Engineering — Thu, 15 May 2008 13:52:00 GMT

The saga of Mike's grandmother's TV continues with another really good question about possibly combining the feeds from several antennas for a better signal. If I am reading his comment correctly, he's thinking of something like this:

The first question is, will this damage anything? Answer: no.

Second question: will this help? Answer: probably not.

Third question: how do I come up with this stuff before my first morning coffee? Answer: I can't. Be right back.

Ahhh... much better. The idea of combining antennas for a better signal actually takes me back several decades to the middle of the CB craze, when I worked for a spell at Radio Shack (oh, the stories!). Every week or so, someone would come in with the idea of boosting their signal by hooking up a bunch of antennas to their rig -- and I had the sorry task of bursting the balloon. Yes, I'd love to sell you $126 worth of stuff... but it isn't going to work. We had one very persistent fellow who tried it anyway: he put four of those really long bumper-mount deals on his AMC Pacer, one at each corner of the car. I didn't think a Pacer could be made to look any weirder, but I was wrong -- this thing looked like it was trying to communicate with space aliens. For sure, he wasn't communicating with other CBs... especially after burning up the output transistors on his radio.

So why do radio stations do it?

AM stations often use several towers in order to shape the pattern in a particular way. It works because the towers are in an exact position and have exact electrical characteristics, and because there's a special phasing network that controls the exact time relationship between the signals leaving each tower. Did I mention that all of this has to be done within very exact tolerances? Exactly so. Oh... the other thing that makes it work is that the AM station's pattern only has to work at a single frequency.

So why wouldn't this work for receiving television stations?

The biggest practical problem is that most people like to watch more than one channel, so the antenna system needs to work well across a whole band... and when you start combining signals it really messes things up. Let's look at what is likely to happen if you try a setup like my sketch in a place like Lowville, where all of the stations are coming from essentially the same direction.

The lowest digital channel is WWTI -- channel 21, or 515 MHz. Each cycle of their transmitted wave is almost 23 inches long as it zips through the air; in cable it's about two-thirds of that length. So if you have two antennas with two lengths of cable coming to a combiner, you would have to trim one of the cables so that its feed matches up in time with the other cable. Let's say you actually manage to accomplish this -- the "sweet spot" is less than an inch long to make the two feeds combine for a peak signal. If you are half of the wavelength off -- only about 8 inches of cable -- the two signals will completely cancel and leave you with nothing. Oops.

Let's say you're persistent and keep at it until you find the peak. Congratulations... now change the station to see what you have on WPBS, channel 45. At 659 MHz, a cycle of WPBS's carrier is much shorter, nearly 18 inches of wavelength in free air. Your carefully calibrated combining network for WWTI actually winds up cancelling most of WPBS's signal. I won't get into the math, but a system that is ideal for channel 21 will be about 100 degrees out of phase on average at channel 45... for a typical system loss of about 14 decibels. Ouch.

Okay, I've burst the balloon, stomped the dream, beaten the dead mule... pick your favorite lame image. What solution is most likely to work? The short answer: one really good antenna, mounted as high as you can get it, connected to a good receiver with good cable. And maybe a rotator.

We'll be looking at antennas very soon... for many people, getting a suitable antenna will be the single biggest obstacle to getting consistently good DTV reception. I finally have all the parts together to start writing the "how-to" guide for making your own Gray-Hoverman UHF panel antenna... so look for that to show up here soon. Retail antenna sales are about where over-the-counter drugs were a century ago: there's just unbelievable quackery out there, and we need to cut through the nonsense. For now, if you see an ad for some gizmo to convert your house wiring into a giant TV antenna... fight the urge. Just say no.

-- Jeff

Losing my terrain of thought

JH Engineering — Wed, 14 May 2008 13:25:00 GMT

Yesterday Mike asked a really good question about why he can receive some stations in a given location, while other stations don't show up. The problem with really good questions is that they're usually really hard to answer... but we'll give it a shot.

Mike's scenario boils down to this: his grandmother lives in Lowville, which is roughly 15 miles from the three Watertown stations' transmitters. Why can't she receive them equally well? This question (as I am posing it for the sake of the discussion) is based on the common assumption that all stations in a given location will have the same coverage characteristics... but that generally isn't the case. It's also easy to assume that since the stations' towers are in apparently close proximity, that they should cover the same areas equally. But as they say in the real estate business, location is everything.

Let's start with our station, WWTI-DT. It transmits on channel 21 with 25,000 watts... a healthy amount of power that meets or exceeds their analog coverage pattern. I ran a study of the signal path from the tower to a spot in the middle of Lowville, assuming a receive antenna 15 feet above the ground. Here's the result:

Imagine that you're standing back from a distance looking at the signal going from the tower (at the left) to the receiver (at the right). The brown line is the ground, and shows the changes in elevation; the darker blue line is the signal. You notice one thing straightaway: the signal would have to go underground for the last three kilometers (two miles), which UHF signals really don't like to do. But things get a bit worse: WWTI's antenna is designed to send most of its signal into the Watertown / Fort Drum area, and the signal headed toward Lowville is only about half as strong:

Hmmm. Still, the distance isn't all that bad, and there's a good possibility that if Mike's grandmother lives on a higher spot on the edge of town, a good antenna can overcome the terrain problem.

So how does WPBS, the public broadcasting station, compare? As Mike observes, their tower is fairly close to WWTI's -- but it's not as close as it seems:

Notice the difference: WPBS's signal is still somewhat blocked by the terrain at the end, but it's a more grazing path than WWTI, where the signal's trying to go 150 feet underground. There are two other differences: WPBS transmits 40,000 watts with a non-directional antenna, so the amount of signal being directed toward Lowville is higher.

Finally, how does WWNY stack up? The plot sure doesn't look encouraging:

WWNY's transmitter is actually closer to Carthage, farther north than the other towers outside Copenhagen. Also, this isn't quite as bad as it looks: the vertical scale is greater, so the actual ground obstruction is only a bit more than with WWTI. But WWNY has two huge advantages going, as least as far as hitting Lowville is concerned: first, they transmit a booming 750,000 watts; second, their antenna is designed to increase coverage into the Adirondacks:

The augmented pattern combined with the very high transmitted power probably explain why she's getting WWNY as well as she does.

So what can she do about this? There are three basic things that come to mind, and we'll be examining them in greater detail over time:

Get the antenna as high as possible to clear obstructions.
Use an antenna that maximizes the pickup from the direction where you aim it, and that minimizes the pickup from other directions. Also, choose an antenna that best matches the stations you are trying to receive -- for instance, in Lowville a good UHF antenna would be a better choice than a great all-band antenna, because all of the DTV stations are in the UHF band.
Install really good antenna cable and make sure the connections are well sealed against moisture.

That's about all I have time for right now... got to hop back onto that roller coaster car before the ride starts again!

-- Jeff

We're back... sort of

JH Engineering — Tue, 13 May 2008 13:12:00 GMT

Perhaps it's been a quiet week in Lake Wobegon... but it certainly hasn't been quiet here. Frenetic would be a better description; broadcast engineering tends to be something of a roller coaster, with extended periods of intentionality rudely interrupted by episodes of sheer panic. For the past week or so I've been in and out of town to deal with a whole range of unplanned and unrelated issues at our different stations... and as I wrote that, one of the stations just sent an email concerning yet another problem demanding time that simply doesn't exist right now. This doesn't happen often, but once in a while we get so overloaded with niggling problems we can only react to, that I despair of actually accomplishing anything that would count as progress. When I unlock my office door in the morning I have a mental list of things to accomplish; on a good day I can go home with most of the items crossed off. We are overdue for some good days, but the prospects aren't terribly good for the next week or so.

Sigh.

Yesterday's newpaper included an interesting letter from a gentleman in Camillus who recently installed a DTV converter box and has discovered the "cliff effect". We're accustomed to the way analog TV behaves as the signal degrades: ghost images show up, the picture gets snowy. If the signal gets really bad the picture will lose color and start to roll. The thing is, the process is gradual, and you can still watch a really poor signal.

Digital TV is a whole different animal -- and this actually applies to digital satellite as well as over-the-air DTV. As your signal goes downhill, the picture remains apparently perfect until it reaches a certain point where it becomes completely unviewable. That mystical point is the "cliff", and you can't tell how close the edge is just by watching the picture.

In this gentleman's case, he has a fairly sizeable outdoor antenna on a rotor, and says that he receives 14 channels. That's impressive: in Syracuse there are only 12 digital channels being transmitted now, so he must be receiving a station from some other market, most likely Utica or Rochester. Interestingly, the stations he has trouble receiving consistently are 68 and 24... which actually transmit digitally on channels 19 and 25 with a substantial amount of power.

Which brings up another difference between analog and digital TV: we're used to the idea that a poor signal can be fixed by installing a bigger antenna or by sticking an amplifier in the line. But for digital TV, less is often more. In general, it takes far less transmitted power to cover an area with a digital signal than to reach the same area with an analog signal. For instance, our Rochester station transmits 316,000 watts analog on channel 13; after next February they will run only 10,500 watts to cover the same area digitally on that channel.

So what's this viewer's solution? It might very well be that on those two channels, he's hitting his receiver with too much signal. I had exactly that problem last week in Elmira, where we installed an Insignia converter box to feed our local station to the cable system. Hooked up the box and went through the setup steps... and was amazed to get only a mid-scale signal reading. This wasn't a signal coming from some cheezy beat up set of rabbit ears... this was a direct sample feed coming straight from the transmitter. We're talking an ideal case here, right? Well, no. An analog receiver would have loved it, but the digital box was overwhelmed. Mae West once said, "too much of a good thing can be wonderful"... but converter boxes don't share her attributes. I finally had to insert an attenuator pad before the converter's antenna input to reduce the signal level... but once I did, the signal meter jumped right up to the top of the scale.

Unfortunately, attenuator pads aren't all that easy to find outside of a specialty supplier. Radio Shack used to sell a variable attenuator: a small box with a coaxial connector on each end and a knob in the middle to set the signal level... but when I tried to find one several weeks ago, it turns out that they have been discontinued. Pity: I expect that a number of people will find that they will need a solution like that.

In the meantime, if you suspect that you might be overloading your converter (this also applies to full-blown HDTV receivers), you can test that theory by getting a four-way passive splitter and three terminations. Screw a termination on three of the splitter's outputs, and run the antenna feed through the splitter to the receiver. (Oh, you'll also need an extra piece of coax cable, a foot or two long.) A four-way splitter will drop the signal about 7 decibels, which should be enough to make a noticeable improvement if overload is the culprit... and you'll actually see the quality meter go up.

Someone's going to say, if the antenna is on a rotor, why not just steer it slightly away from the station? Won't that lower the level and accomplish the same result? Been there, tried that... doesn't generally work. The problem is that while yes, it lowers the direct signal level, it also increases the amount of crud that's reflected from other surfaces... which makes the situation worse.

I'll do some research one of these days and give you a few places where you can get proper attenuator pads and other antenna supplies... assuming that the roller coaster ride slows down. For right now I'll leave you with a charming sight: a $60 converter box installed at a broadcast transmitter site doing the work of a $1,500 professional receiver that failed last week. And it's delivering a better picture than the "professional" box. So I suppose we made some progress, after all.

-- Jeff

Comparing converters: which has the best reception?

JH Engineering — Fri, 02 May 2008 17:47:00 GMT

Several days ago we looked at my pile of converter boxes and compared the quality of their pictures... today we'll look at how well they perform on the receiving end, and how well they handle a poor signal.

We're used to how a bad signal looks on an analog TV: the ghosting and snow, sometimes tearing and rolling if the signal gets really bad. Still, there's a recognizable picture to be seen.

DTV is a different animal: weaken the signal a bit or add some distortion, and the picture looks just as good as if we had a perfect signal. Knock the signal back some more, and the picture still looks perfect. Keep dropping the signal enough, and you suddenly go from wonderful to nothing at all... or at least, to a blocky mess. What does it take to have a consistently great picture? First, a receiver that is both reasonably sensitive and yet tolerant of distortion; second, an antenna that delivers a good signal to the receiver; and third, a receiver that gives you a useful indication of how good the signal is. Right now we're looking at the receiver issues... antennas will come later.

When we talk about signal quality, most people think of stregnth first. A typical cure for a poor signal has traditionally been to insert an amplifier in the line to boost the signal... but that doesn't necessarily work for DTV. Quality also depends on keeping out the stuff that doesn't belong. Let's look at the most common probem:

Ideally, you will have an unbroken path between the transmitting tower and your antenna... that's the gold arrow. You want as few obstructions as you can get -- trees, buildings, hills, and so on. In the real world, you also have things that will reflect the signal like buildings, water tanks, and trucks driving past your house... as in the dotted salmon-colored line. One might think that picking up the reflections can be a good thing: it adds to the signal, right? Well, yes... but what it adds is delayed, because it took longer for the signal to hit the other object, bounce off it, and then travel to your antenna than it takes for the "real" signal to come directly from the transmitter. That delayed signal winds up adding stuff that doesn't belong, and cancelling out the stuff you need. Sticking an amplifier in the line won't fix the problem -- it just kicks up the reflections right along with the signal you want. If you amplify the signal enough, it actually makes things worse rather than better: the stronger main signal gets chopped off at the amplifier's limit while the reflections still get boosted, making it even harder for your receiver to tell the difference between what is real and what isn't.

How do you fix this problem? The best way is to choose an antenna that is most sensitive to signals where you point it (toward the transmitting tower, we hope!) and least sensitive to signals coming in from other directions. The next thing is to pick a receiver that's especially good at locking to the true signal, and ignoring the other crud that shows up.

All right, already! How well did the receivers work?

I've tested the bunch at my house (buried in the valley, obstructions between the transmitter and my antenna but lots of things for the signal to bounce around on... a digital version of bumper pool). I also tried them at the station, which isn't much of a challenge since we can walk out the door and see the tower in Pompey.

The LG-made receivers (the Zenith and Insignia) worked the best. They're the quickest to lock to a weak signal, and slowest to break up or black out when the signal gets bad. You can call up the on-screen signal display with a single button on the remote, and a beeping sound gives you a way to aim your antenna without having to keep your eyes glued to the screen.

The Magnavox receiver was nearly as good at keeping a locked picture as the LG twins, but getting to the signal quality display is an annoying procedure that requires going through several menus. There is no audible indicator. The display also blocks most of the picture, making it harder to see what's going on with the station's picture.

Third on the performance scale was the Digital Stream... not by a huge margin, but enough that you might want to look first at the LGs if you live in an area with difficult reception. It was the first to break up and the last to restore good video. This is unfortunate because the main quality display is rather nice looking... even though you have to go through menus to get there. It also does not give an audible quality indication.

On the plus side, the Digital Stream is the only converter that gives you a signal quality reading with the station information -- and that is a single button push.

Next week I'll try to get back to our homebrew Gray-Hoverman antenna project... by coincidence, one of the trade magazines that showed up on my desk this morning has an article about it. Apparently we're ahead of the curve! Have a good weekend --

-- Jeff

Strange morning

JH Engineering — Thu, 01 May 2008 15:33:00 GMT

Today marks an odd milestone: starting today I can’t pick up the phone, dial our competing station on James Street, and be greeted by “Good morning, WSTM Engineering... Gary Hartman.” His desk sits empty today after fifty years.

When he started back in 1957, channel 3 was shoehorned into the Kemper building, a block from Hotel Syracuse. Videotape had been invented the year before, but hadn’t come to Syracuse yet. Color was still in the future, and stereo wasn’t even on the horizon. Channel 9 – we were WNYS back when they were WSYR-TV – wouldn’t go on the air for another five years. His career spanned generations of technology: film was replaced by “portable” video cameras and recorders; tape gave way to computerized editing and playback. From racks filled with tube-type gear to the newest miniature computer-driven systems, he has installed it, operated it, and kept it running. Portable microwave... satellite transmission... digital high-definition broadcast.

For fifty years he has been ready, when the phone rings at home, to talk someone through solving an equipment problem. Often he would hop in the car and hustle back to the station to fix whatever had failed. Sometimes he would take me with him on these unplanned expeditions, and I would watch as he’d drive, his mind already churning through possibilities, narrowing down what the problem might be, and planning what he could do about it. You see, Gary Hartman wasn’t just their engineer... he is also my Dad.

He would bring me along on radio remotes at Archbold Stadium – I was still in grade school – and he taught me the craft, mainly by example. How to connect the mixer. How to set up the shotgun microphone to pick up the band. And most important: if you have a cup of soda, keep it at a safe distance from where you’re working. Warm soda attracts bees.

More than the skills particular to broadcast engineering, he taught me about work: sometimes it can be difficult, but it’s rewarding, too. Make a diligent effort to keep learning, and you will get to see and do fascinating things. Work can be fun!

Today might begin his first day of retirement from channel 3... but he is still learning, and there remain fascinating things yet to be seen and done.

Congratulations, Dad!

-- Jeff

Comparing converters: which has the best picture?

JH Engineering — Tue, 29 Apr 2008 21:06:00 GMT

The coupon just arrived and you're thinking about buying a converter, right? Problem is, most stores only sell one or two models, and many don't have one hooked up for you to watch. So how can you compare what's available to make the best decision for you?

For the next few posts we'll compare the most easily available converters and give the results. If someone tells you they're all pretty much the same... wrong. Each has strengths and weaknesses that you will want to know right up front. Some differences are matters of preference: how you like the program guide to be set up, for instance. Other things can be measured... like today's tests of picture quality.

We're looking at four different converters:

Magnavox TB100MW9, available at WalMart
Digital Stream DTX9900, available at Radio Shack
Insignia NS-DXA1, availble at Best Buy
Zenith DTT900, available at Circuit City and Radio Shack

The Insignia and Zenith boxes are virtually identical except for the front trim plate -- they're actually made by LG Electronics (which oddly enough doesn't market the device under their own brand).

Test 1: How accurate is the picture?

Each box was connected to the professional-grade antenna at our studio and tuned to digital channel 9-2; its video output was connected to a Videotek test set. We also connected the main studio feed for channel 9-2 to the test set so we could directly compare the converter box's picture against the original signal we transmit.

The Magnavox TB100MW9 fared the poorest in our tests: it produced video that was somewhat darker overall than the original picture, and very light colors tended to be washed out, reproducing as white instead of the intended hue. This was particularly apparent in facial highlights, where skin tone on cheekbones and foreheads tends to break into white.

We had better results with the Digital Stream DTX9900: highlights were reproduced properly, but the entire picture was slightly lightened. Blacks, for instance, reproduced as very dark grey rather than pure black.

The best results came from the LG-made Insignia NS-DXA1 and Zenith DTT900 twins, which produced video levels almost exactly matching our studio feed. (In fact, the accuracy of the LG boxes was slightly better than our professional Sencore receiver... but then, our Sencore is five years old.)

Test 2: How detailed is the picture?

Using the same test setup, I inserted a test signal into our picture to see how well the converters could reproduce fine detail. Naturally, a standard definition converter won't give you the performance of a high-definition display, but all of these converters produce a noticeably more detailed picture than you could get with regular analog reception. Still, there were apparent differences between the boxes.

The Magnavox reproduced the test pulse fairly accurately; it was not quite as prominent as the original, but close -- about 92%. Edge details are a bit exaggerated, apparently in an attempt to make the picture look sharper. This isn't a problem most of the time, except when the original picture is noisy -- and it has the effect of slightly accentuating the noise. Still, the picture is generally quite pleasing.

Digital Stream seems to have taken an opposite strategy, and has opted for producing a picture with noticeably less apparent noise. While this gives the edges of text a nice smooth look, it also reduces actual picture details. The test pulse was only about 65% of the original, and the whole picture has a distinctly soft look compared to what we transmitted.

Once again, the Insignia and Zenith came out on top, reproducing the test pulse at exactly the right level. Moreover, there was no sign of either over-enhancement (as with the Magnavox) or over-filtering (as with the Digital Stream).

So... which one is right for me?

If you want a picture that most closely resembles what the station transmits, go for the Insignia or the Zenith. Either one will cost you about $60, or $20 with the coupon.

If cost is most important, or if you prefer a picture that's a bit sharper than normal, go with the Magnavox. It's just under $50, less than $10 with the coupon.

If you have a TV set that already makes noise too apparent and you want to tone it down, the Digital Stream would be the pick -- it's about $60, $20 after the coupon.

Hang on a bit before heading to the store... picture quality is only one difference. Next time we'll take a look at how well the boxes handle less-than-deal signals.

-- Jeff

The last box in the pile: Digital Stream DTX9900

JH Engineering — Fri, 25 Apr 2008 21:23:00 GMT

It’s been a fairly busy week again... not so frenzied as last week, but enough to keep me away from my desk. Remember the backup transmitter I wrote about last week at our Elmira station – the 50-year-old GE, built right here in Syracuse? Well, it got promoted late last week when their main transmitter’s final tube died, and has been chugging happily along ever since. Once again, hooray for well designed and well built equipment!

Now for a look at the last DTV converter in my pile, made by a company I’ve never encountered before: Digital Stream. Researching the web turns up their company web site: it is mostly written in Korean, peppered with English phrases like “transformation consultation” – that’s what they call their help line. It appears that Radio Shack contracted with this company to make a coupon-eligible converter for their stores. At least there are a lot of Radio Shacks around to handle questions: I don’t think you’re going to get much help from Digital Stream, unless you speak Korean.

At $59.99 ($19.99, less the coupon), the Digital Stream is the same price as the Zenith / Insignia and $10 more than the Magnavox. The packaging is the most impressive of the batch – a well-printed carton with a molded cardboard insert tray, and a fold-up map style instruction brochure printed on glossy paper. Evidently the folks at Digital Stream spend their attention on product appearance and function, rather than on their web site.

What's in the box

Inside you’ll find the usual stuff: the converter, a remote with battery, an antenna cable, and the glossy manual.

Hooking it up

Having hooked up three other converter boxes by now, there should be no surprises... and there weren’t. If anything, the Digital Stream is the easiest to set up: there’s a switch on the back to select whether it feeds your TV on channel 3 or 4. I like that touch much better than having to drill through a bunch of menus to change the output channel. Once you turn it on, the on-screen instructions walk you through the rest of the setup process quickly and easily. Of all of the converters tested, the Digital Stream finds available channels the fastest... and shows you the growing list as it finds them.

How does it look?

The picture and sound are very good, though the picture is a bit softer than the Zenith / Insignia twins, and the Magnavox. I spent part of this morning looking at all of the converters on our test equipment, and there are some real differences... but we’ll get into that next week. The Digital Stream is also bit more finicky about the quality of the antenna feed than the other converters; if you live in an area with difficult reception, this might not be the best choice.

How easy is it to use?

Earlier I had commented on Digital Stream’s attention to appearance; that becomes most apparent when you look at the remote control and see the on-screen menus and displays.

The verdict isn’t unanimous about the remote: it’s my favorite of the bunch because the buttons are distinctly different, and the shape of the remote fits my hand better than the rather slender Zenith / Insignia. My wife and daughter, on the other hand, find the labeling less clear. In any case, the functionality is very similar to the Zenith / Insignia, and far better than the Magnavox. You can turn the TV on and off and control the volume with this remote.

One minor quibble has to do with the zoom control: while the Zenith / Insignia remembers zoom settings for each channel, the Digital Stream’s zoom applies to all. If you’ve been watching Good Morning America in widescreen form on channel 9-1 and change the channel to 9-2, you will see a small picture with black on every side until you change the zoom setting. Not a deal breaker, but not as nice as remembering that I like to watch 9-2 full-screen.

On-screen displays are really nice... easy to read, informative and intuitive. We’ll spend some time next week comparing how the different boxes present themselves.

One thing to consider: if you want to have separate converters for your television set and for your VCR – to be able to record one program while watching another – you might want to buy different brands so that you can control one without disturbing the other. A Zenith / Insignia would be a good choice for the TV, and this Digital Stream would be my pick to feed the VCR.

What's the bottom line?

Overall, the Zenith / Insignia (identical units made by LG) is still my favorite, but the Digital Stream is not far behind.

It’s not the cheapest converter, but $20 after the coupon is reasonable
Setup is the fastest in the bunch
Picture and sound are very good, though the picture is slightly soft
The remote control is easy to use, yet gives you a lot of useful functions
The receiver is a bit less tolerant of a poor signal, and is quicker to break up than the other converters
On-screen displays are fantastic; the electronic program guide lets you see farther into the future than the other converters

Let’s give the Digital Stream a high B+.

Next week we’ll look at the units side-by-side, and compare video performance and on-screen displays. I’m hoping to finish up the prototype antenna this weekend and get it permanently mounted outdoors... then I’ll start putting together a step-by-step description of how you can do it yourself.

Have a great weekend!

-- Jeff

Is your homeowner's association digital-ready?

JH Engineering — Fri, 25 Apr 2008 17:04:00 GMT

The Federal Communications Commission just announced that it is looking into whether several homeowner's associations have the right to restrict or ban antenna installations; they will accept comments from interested parties until the end of May.

This has been a hot-button issue in some neighborhoods and towns that try to prevent homeowners from installing antennas and dishes on their houses, claiming that they detract from the appearance of the community. More than ten years ago the FCC got involved in this dispute, taking the position that the right to receive satellite and over-the-air programming without unreasonable cost or inconvenience trumps local rules... but that hasn't put an end to the wrangling.

For people receiving their television over-the-air, the outcome of this debate will be quite important: many people will probably need to have an outdoor antenna to receive digital TV reliably.

Read more about today's announcement here.

The FCC's existing rules about over-the-air reception devices are here.

-- Jeff

Cloning around: Zenith DTT900, Insignia NS-DXA1

JH Engineering — Mon, 21 Apr 2008 20:57:00 GMT

One of the problems with adopting future technology is having to keep the old stuff working at the same time... and older equipment seems to have a well developed instinct for the worst possible moment to fail. Last week we were under a full-scale assault: devices ranging from the main analog transmitter down to a lowly connector at a cable head-end, ganged up and carried out a well coordinated attack that kept us running from one crisis to another. We seem to have won the battle for now: things are much quieter, and I actually have time to sit down to lunch, though it’s at my desk while writing today's post.

A quick note: the home-brew antenna has spent the last few days in my attic, where it works surprisingly well in spite of nearby aluminum siding. My existing antenna – a fairly large name-brand model on a rotator, feeding an amplifier – yielded only a mid-scale signal quality reading. This home-built antenna, mounted in a fixed position without any amplifier and split to feed two receivers, gives a much better reading on every channel. One of these days I’ll finish the thing up and install it outdoors where it belongs... and I’ll also write up the instructions so that you can try making one yourself.

Now, finally, back to the pile of converter boxes on my dining room table. Two of the four appear to be suspiciously similar: the Zenith DTT900 (available at Radio Shack and Circuit City) and the Insignia NS-DXA1 (Best Buy). In fact, they turn out to be identical devices, except for slightly different front panels and packaging. Insignia is Best Buy’s house name; Zenith is a more traditional American brand. What’s in a name? Nothing, apparently: both boxes are actually a product of LG Electronics, a large and growing South Korean conglomerate, and they are built in China. They both sell for just under $60, less than $20 after the coupon.

Even though the boxes themselves perform identically, there are some minor differences between the Zenith and the Insignia that we might as well get out of the way. First, warranty support: Zenith has you call a toll-free number, presumably to arrange for the unit to be shipped; Insignia just has you take the box back to Best Buy. Second, the instruction guides are surprisingly different. The Insignia manual is more comprehensive but the smaller type and grey paper make it harder to read. The Zenith manual is quite legible, but less detailed. None of the differences seem like a big deal; the boxes are easy enough to set up and use, so I imagine a lot of the manuals will never leave the carton.

Since the Zenith and Insignia operate and perform identically, I’ll treat them as the same LG units they actually are.

What’s in the box

Like the Magnavox I reviewed last time, these LG twins include the converter, remote with battery, an antenna cable, and manual. In addition, the LGs throw in an audio/video cable set so you can plug directly into your TV and get a somewhat better picture.

Hooking it up

If you tend toward guy-style installation – who needs instructions? – you’ll find that the LG, like the Magnavox, is easy to install, and sets up very much like a VCR. There’s just one “gotcha” waiting for the unwary: the battery for the remote control comes wrapped in nearly invisible tight-fitting plastic. If you don’t notice and remove it, you’ll spend a lot of time wondering why the remote doesn’t work. (And no, the instructions don’t warn you about that!) Once hooked up and powered on, the box quickly found all twelve digital program channels with no fuss.

One feature unique to the LG models is the signal strength indicator: not only does it show the usual bar scale on the screen, it also makes a beeping sound that gets faster as the signal quality improves. It’s rather handy, not having to keep an eye on the screen while adjusting the antenna.

How does it look?

The picture and sound are excellent – indistinguishable from the Magnavox, and on par with the pictures we see in the control room. I’m still amazed to be watching such a good picture at home. The receiver seems to marginally outperform the Magnavox and Digital Stream, resisting signal dropouts and locking more quickly to a somewhat weaker signal.

How easy is it to use?

Here’s where the LG-made converters really shine, especially compared to the cheaper Magnavox. All of the functions you will want to use most often are right on the remote control.

Adjust the volume or mute it? No problem. Turn the TV on or off? The button’s right there. Change the picture from wide-screen to center-cut? Just hit the Zoom button. Captions? The CCD button steps you through all of the closed caption and teletext services. Yes, there are also menus for less frequent settings... but the menus are easy to navigate and the functions are fairly intuitive. If you lose the remote, the converter still has power and channel-select buttons right on the front panel; you aren’t stuck with a dead box, like the Magnavox.

While we’re on the subject of remotes: the Zenith and Insignia remotes are interchangeable, and each will control both LG-made boxes. If you have two converters in the same area – one for the TV, another to feed a VCR, for instance – this could be a problem. The LG remotes use different codes than the Magnavox and the Digital Stream (yet to be reviewed), so you could easily pair an LG with one of the others.

I’ll compare the on-screen graphics on all of the boxes in a later post, when I have screen shots to show. But for now, the LG does a nice job, and tells you what you need to know quite adequately.

What’s the bottom line?

Right up front, I’ll say that overall, the LG is my favorite of the bunch.

It’s not the cheapest converter, but $20 after the coupon is still quite reasonable
Setup is quick and easy
Picture and sound are fantastic for standard definition
The controls are easy to use and do everything you want without a lot of fuss
The only weak spot is the electronic program guide, which could display a bit more information about upcoming programs

All in all, the Insignia / Zenith would be my first pick: let’s give it an A–.

-- Jeff

Murphy's Law applies to transmitters, too!

JH Engineering — Wed, 16 Apr 2008 13:11:00 GMT

Two days ago I wrote about next February's shutdown of analog transmitters that have run faithfully for decades. Well, our main transmitter -- a relatively new Harris (it's only 25 years old) -- decided to jump the gun. Early this morning one of its power supplies died in a cloud of smelly smoke.

We're on the air right now with the station's very first transmitter: a 1962 vintage RCA TT-11. The picture looks pretty soft and there's a noticeable ghost in it (no, not the Baron!). It takes a while for it to warm up, and then a fair amount of tweaking to get it looking good... but eventually it gets there. Quite impressive, considering that there isn't a single transistor in the thing: this is our last piece of entirely tube-type equipment, for which "warming up" is the literal truth, not just an expression. It's also quite large -- especially compared to our DTV transmitter, which is the size of a high-end refrigerator. The RCA is as big as an RV, but a lot heavier... and you actually walk around inside the thing to work on it (but not while it's running).

At least this doesn't affect Time Warner cable subscribers: they get a direct feed from our studio, so transmitter problems don't affect them.

Equipment just seems to know, somehow, when its days are numbered... and it goes out of its way to be ornery while it still can. C'mon, guys... just ten months to go...

This is not a good way to start a day.

-- Jeff

Pipe dreams

JH Engineering — Tue, 15 Apr 2008 21:46:00 GMT

For a limited time, special bonus points if you can guess what this is (or, I should say, what it's going to be):

Is it an irrigation system for a miniature golf course? Nope.

A Bavarian weasel trap? Sorry, wrong answer.

Since it's in this blog, could it have something to do with digital TV? Close enough -- you win a lifetime supply of free over-the-air high definition TV!

It's the frame for an antenna that was invented in the early 1960s, but never caught on because it only covers UHF channels from 14 to the mid-50s. As it happens, that's the same range of channels being used for DTV in the Syracuse area, which could make this antenna just about ideal. I'm giving it a shot, and if it works as well as the paperwork suggests, I'll write up how you can make one for yourself, using material you can get at any home improvement store.

That's ordinary 1/2" PVC water pipe, which I cut to the various lengths last night ...much to the annoyance of Sasha, the persistent squirrel that lives in the barn behind our house. Every time I shut off the radial arm saw, Sasha would start chattering and pitching nut shells down from the loft, hoping to chase me away. Last time I checked, my name was on the mortgage... so I figure I have a pretty good claim to work in the barn once in a while.

The frame is rather ugly right now... that's purple PVC primer you see splashed all over the thing. But once it's built and tested, a couple coats of spray paint will make it look quite presentable.

Oh, yeah -- I love to build things. But if you read last Monday's post, you probably would have guessed as much. It's also a good excuse to get away from the paperwork in my office, and work outside in the fresh air for a couple of hours.

-- Jeff

Some changes are better than others

JH Engineering — Mon, 14 Apr 2008 22:08:00 GMT

Next February marks the end of one era of broadcasting, and the start of another. The obvious change is the shutdown of this country's analog full-power television stations, to be replaced by more efficient and higher quality digital transmissions.

It's also the end of a chapter in Syracuse's history, as the last television broadcast equipment designed and built at GE's Electronics Park comes out of service. If you're old enough to remember Baron Daemon, chances are good you watched him on a TV that came out of building 5; our audio amplifiers and very first color cameras were made in building 7. To this day, we still have several BA25 audio preamps that work just as well as they did when we signed on the air in 1962.

Many stations around the country still operate transmitters built in Electronics Park:

This is the standby transmitter at our sister station in Elmira. It takes up a fair portion of the room, not counting the transformers, blowers, tanks and miscellaneous plumbing fixtures -- the massive tubes are water cooled. It's older than most of the people who operate it, but it still fires up when needed. At WUTR, our former sister station in Utica, their GE transmitter has been kept on the air all day, every day for decades by their skilled engineers. That's right -- decades. How many things can you think of that are built that well?

One day early next year, these faithful rigs will be shut down, their tubes cooled, and the recirculating pumps stilled for the last time. Antennas will be switched over to new transmitters, most made in other parts of this country, sending signals to converters and widescreen receivers made overseas.

Television was born and grew up in this country: giants like RCA, Ampex, and General Electric created much of the technology that we take for granted. Videotape... compatible color... electronic graphics... all invented and made practical in America. But today you will be hard pressed to buy a videotape recorder or a DVD player made in this country, even if the box has a name like GE or RCA or Zenith on the outside. The coupon-eligible converter boxes we've been talking about? All of the ones on my table were made in China, two for their Korean parent company.

Remember General Electric's slogan: "Progress is our most important product"? The technological advances coming into our living rooms are amazing... but when I drive down Electronics Parkway past acres of empty parking lots, what I see sure doesn't feel like progress.

-- Jeff

My first converter: Magnavox TB100MW9

JH Engineering — Fri, 11 Apr 2008 19:15:00 GMT

So there I was in WalMart doing the usual errands, when I notice this stack of cardboard cartons on the shelf with bold type proclaiming “You can use $40 Coupon,” and inviting me to WATCH FREE DIGITAL TV PRGRAMS with my analog TV!

Cartons have a hard time with grammar and spelling, but it was enough to excite me – until I realized that my coupons were at home on my desk. It was the first time I had seen an actual converter in a store, ready and waiting to come home with me... and that was enough to bring me back the next day, coupon in hand, worried that the store might have sold out of them.

As it turned out, my worry was unfounded: the stack appeared to have been untouched, the demand evidently not up to Wii-before-Christmas levels. I grabbed a box and took it to the checkout counter, where the cashier gave the coupon a look and smiled, “so that’s what they look like!” But she knew what to do with it, and I took my first step into the digital future, having spent only $9.87 plus tax.

What’s in the box

It took major self-control to not open up the box right there in the car, but I managed to wait until getting it home and onto the dining room table before taking a look:

My first reaction was, “Is this all?” The converter is about the size of a hardback book, with a handful of connectors on the back and no controls other than a main power switch on the side. There’s a remote control with batteries, an antenna cable, and the manual. Sure, the thing cost me less than ten bucks... but it felt unimpressive, somehow. Hope it works.

Hooking it up

Please... I’m a guy! Besides, how hard can it be? Ordinarily that would be the cue for a blinding flash and a cloud of smoke, but the converter was ridiculously easy to install. Put the batteries in the remote, move the antenna plug from the TV set to the converter’s antenna input, and hook the new cable from the converter’s output to the TV set. Just like hooking up a VCR. Hit the power button on the remote, and... nothing. Turns out the converter comes out of the box expecting your TV set to be on channel 3, and my TV was on channel 4. Easily fixed, and I was greeted with a display that guided me through the rest of the setup. It stepped through every channel to see what it could find, and automatically programmed itself... exactly like my last VCR.

As I’ve said before, I live in the Valley, where off-air reception means ghosts and snow year round, not just in the winter. I was stunned when the box recognized every single DTV station in town without my having to mess with the antenna once. Real-world things are not generally this simple.

How does it look?

In a word: amazing. I can flip through all of twelve DTV program channels and get pictures and sound that look like what I’d see on a monitor in the control room. The funny thing is, I expect this at work: it never dawned on me that my TV at home could look so good... and it isn’t remotely close to high definition. Wow. This Magnavox box sure doesn’t look like much, perched on top of my TV set, but it sure does make a nice picture.

How easy is it to use?

Ay... there’s the rub. While the converter box just seems cheap, the remote control actually is. The buttons you use most often are small and packed together in no obvious order; the labels are hard to read. But with the Magnavox, you’d better get used to it: there are no controls on the converter itself, so if you lose the remote, the converter is useless. You can’t even turn it on.

But the problem goes deeper than a cheesy remote control: the designers as Funai (the Chinese company that actually manufactures this for Magnavox) apparently have no feel for making something easy to use. Want to turn on closed captioning? You have to drill through a series of menus and options. Want to change from widescreen to normal screen size? More menus. Want to change the volume or mute the audio? Oops... you can’t. You also can’t turn off the TV, a standard feature on other converter boxes I tested. Fie.

Surprise!

Despite the pitiful remote, I was quite pleased with the box and played with it for long enough to annoy my wife and daughter, who tend to be more interested in the program than in the box playing it. Mercy prevailed, and I left things alone and went about various other chores. About four hours later came the dreaded words:

“Honey, your new box just died.”

Indeed it had... but the remote turned it right back on. What I had forgotten is that all of these converter boxes, in order to be eligible for the $40 coupon, must be energy efficient: which means that they shut themselves off unless you disable that “feature.” Yup, you guessed it: more menus.

What’s the bottom line?

It’s the cheapest converter I’ve found, about $10 less than the competition
Setup is quite easy, even if you’re a guy and don’t read directions
The picture quality is outstanding
Controls are the weak spot, clumsy and inconvenient
Don’t lose the remote. The converter won’t work without it

There are more features that deserve mention, like the electronic program guide, but they will keep for later. All in all, I’m giving the Magnavox a C+.

-- Jeff

Where's my coupon, already???

JH Engineering — Thu, 10 Apr 2008 18:23:00 GMT

Yesterday, commenter Lisa White asked about the status of her coupons: it seems that she applied for them on line in January, but they still haven’t arrived.

The process takes several steps:

You apply, either on line or by mail,
The NTIA approves the application,
The coupon card(s) are generated, along with a short list of nearby stores that sell eligible converter boxes,
The coupon is sent out via standard (not first-class) mail,
The coupons arrive at your home.

According to the NTIA’s web site, if your application was approved in January you should see your coupons any day now. There’s a table on their web site that explains when they expect to mail out the coupons... better yet, if you scroll down the page you can enter your address and check the exact status of your cards. Click here to check.

Thanks for the question!

-- Jeff

Do I really need a converter?

JH Engineering — Thu, 10 Apr 2008 16:04:00 GMT

Alert reader Jeff (not me, a different Jeff -- it’s too early for me to be alert) asks:

“I have heard that if you have cable or satellite service, the converter won’t be necessary. Is this true?”

That is true... for now. It isn’t clear to me how much longer cable and satellite providers will be required to support existing analog sets, but the last indication I saw was that it will be at least several years before it becomes an issue to them.

If you’re reaching for the phone to subscribe to a service, hold on... there are some tradeoffs you should consider. First, a disclaimer: I have my own preferences (who doesn’t?), but will make an effort to be objective.

Cable TV:

Pro: Lots of channels
Pro: Delivers a good signal to areas that get poor over-the-air reception
Pro: Local stations are available, some in high definition
Pro: No antenna, and in many areas no visible wires outside the house
Pro: Service and repair are generally prompt and easy to arrange
Con: Substantial monthly fee
Con: Not available everywhere
Con: Analog cable quality can be fair-to-poor in some areas
Con: Power outages or downed wires sometimes disable service

Satellite TV:

Pro: Lots of channels
Pro: Delivers a very good signal to areas where over-the-air reception and cable are not available
Pro: All channels are digitally transmitted, so quality can be quite good
Pro: Power outages and downed wires aren’t an issue (assuming your own power is on)
Con: Substantial monthly fee
Con: The dish antenna is not the most attractive thing to bolt to the side of your house
Con: Availability of local channels is spotty, and sometimes of inferior technical quality
Con: Signal can be blocked by heavy rain or snow

Over-the-air digital TV:

Pro: More program channels than analog
Pro: No monthly fee
Pro: Better technical quality than cable or satellite
Pro: No outdoor wires or dishes in many areas
Pro: You own and control your own equipment
Pro: Works with portable receivers
Con: No “premium” channels
Con: You are responsible for maintenance and repair
Con: Some areas make for difficult reception and might need a special antenna

There’s no “right” answer... it comes down to what you expect and what you’re willing to pay for it. In my home we watch over-the-air with an antenna in the attic; the analog signal isn’t terribly good, but I figure we have saved roughly $5,000 since disconnecting the cable about ten years ago. It was a bit tough at first: my wife loves sports and really missed ESPN (she cheers on her team... I count the cameras!). But it’s no big deal now... and there are plenty of other things to do with the time and money. And don’t get me started about the companies that want to sell you “free HD”... in my book, if they decorate my mailbox with a bill once a month, it ain’t free. But that’s my own personal take on it.

The DTV converter box is the best thing to hit our TV since the set came out of its packing box. Before, we got seven full-power analog stations poorly (we’re in the Valley, where it’s Ghost City)... now I get twelve digital sub-channels with no ghosts and no noise. I want to improve our antenna, but already the difference is absolutely amazing... and it cost me less than a single month of subscription TV. I’m thinking that even if I had cable or satellite, I would probably still spring for at least one of these boxes: they’re cheap, and if we have another emergency like the Labor Day storm, the box will keep working even when the cables are down in the road and the dish has been blown two counties away.

Alert reader Jeff also earns double bonus points for catching the typo on Magnavox’s packaging: it does indeed say “PRGRAMS”. It just goes to show how rushed this whole converter box program has been... and also illustrates a fairly common problem with products made in non-English speaking countries. Or perhaps they just didn’t want to buy a vowel. We drp unnecessary lettrs and pass the savngs on to yu! Time for a vowel movement, anyone?

-- Jeff

Older TV seeking an eligible converter box...

JH Engineering — Wed, 09 Apr 2008 19:12:00 GMT

Perhaps you’ve already seen the boxes on the store shelves with stickers and labels proudly proclaiming that they are eligible for the $40 coupon program... and you’re wondering just what makes one box eligible while another box isn’t?

The National Telecommunications and Information Administration (NTIA... part of the US Department of Commerce) created the coupon program as a low-cost way to keep older televisions working after analog transmitters are shut down. You can plow through a rather long list of their requirements and how they decided on them here, but these are the high points:

To be eligible for coupons, a converter must:

Receive and decode all ATSC DTV formats – including high definition
Create a standard definition output
Provide an RF feed to plug into an analog TV’s antenna input
Provide analog audio and composite video to plug into an analog monitor
Come complete with a remote control, batteries, and an antenna cable
Meet FCC requirements for features like closed captioning, V-chip parental controls, and Emergency Alert System compatibility
Automatically power itself down after a few hours (you can disable this “feature”, but the manufacturer must ship it enabled)
Include a light to let you know the unit is on
Produce a signal quality display to help you adjust the antenna
Display the electronic program guide information that stations transmit

Eligible converters may, optionally:

Include an S-Video output
Pass analog signals through to the TV when the converter is shut off (so you can still watch low-power stations, which aren’t required to shut off yet)
Include extra cables, for example RCA cables for audio and video
Provide support for “smart” antennas that automatically aim for the best signal

Coupon eligible converters must not:

Produce a high definition output
Include any other kind of output... no HDMI, no component, no VGA
Do anything other than convert DTV signals to analog (for instance, the box cannot include a recorder)
Be bundled as part of a package (converter plus antenna, say)

Some of you must be asking, “That sounds like a recipe for a really cruddy little box – why would anyone want one? Why don’t they let me apply the forty bucks to a true high definition receiver?”

The NTIA’s main interest is public safety: making sure that people can afford to keep their existing TV sets going so they can get emergency information. Limiting the box's features holds the cost down and forces manufacturers to create a workable entry-level product.

The funny thing is, I’ve been testing four of these boxes for several weeks and they definitely aren’t cruddy. Some are better than others, but even the worst gives me pictures and sound so good that I would be hard pressed to tell them from a direct studio feed. No ghosting... no buzz... no snow. It might not be high def, but it’s the best picture I’ve ever had in my living room – and the priciest box still cost me less than $20 after the coupon.

What do these converters look like, and how do they compare? That’s the stuff for the next week or two. Stay tuned!

-- Jeff

A Microsoft mornin' to ye!

JH Engineering — Wed, 09 Apr 2008 13:45:00 GMT

It’s that time of the month... the morning after the second Tuesday, the holiday our computers faithfully observe: Windows Update Day. For now the celebration lies dormant, the only sign being a small picture in the corner of each monitor showing the world, dominated by Microsoft’s logo. No symbolism there, eh?

For the next several hours I’ll be diverted from useful work to babysitting several dozen computers as they install their mysterious updates, reboot, and hopefully come back to a productive life without taking any of the stations off the air.

Several years ago a friend who, like me, came to work for channel 9 when we were in the basement of Shoppingtown, lamented: “computers have taken television out of television.” How right he was.

The control room used to be a center of quiet frenzy with its unique sounds and smells: the chatter of a projector pulling a movie through the gate; a waft of ethyloid film cement; the aroma of warm lubricating oil; the sharp whine from the videotape machine’s head, spinning like a dentist’s drill on air bearings. Terse commands to roll and take and flip mirrors and advance slide drums, punctuated by the occasional annoyed grunt when the start of a spot got clipped or a tape didn’t quite lock up.

Every show and every commercial that played was on a piece of film, or a reel of tape, or an audio cart with a handful of slides... and the master control engineers spent their shifts in a constant push to get the next film threaded and the next tape cued just in time to air. An exciting place, and one where you learned early not to stand in the way. I would get home around two in the morning after signing off the station, so wired that it would take hours to fall asleep.

Nowadays the control room is filled with computers, and the atmosphere is completely different... rather laid back, by comparison. Even the old comforting smells are gone, replaced with the distant aroma of someone’s lunch. It’s sad, somehow... but exciting, too. This new gear is what makes DTV possible; and today you can see a picture in your living room that is so far better than what we could produce in the control room even ten years ago... there’s almost no comparison.

But for now it’s Windows Update Day, and I have babysitting to do. Twenty-five years ago, who would have thought this would be the future of broadcast engineering?

-- Jeff

Got coupons?

JH Engineering — Tue, 08 Apr 2008 15:39:00 GMT

By now you might be wondering if you need to replace that trusty console TV in your living room before next February. Sure, you watched the moon landing on it, but it’s got lots of life left in it... and the genuine pecan finish cabinet matches the furniture. Or maybe you have a small set in the bedroom and hate the idea of just tossing it out.

As the pitchman says: there’s some bad news and some good news.

The bad news is, the full power TV stations your older set receives will all be shut down next February... and unless you enjoy watching snow (and we already get enough of that around here!), you need to do something about it.

The good news is, all you need to do is hook up a little converter box to your TV... and it’s really easy to do. You can have the thing running in less than five minutes, a bit longer if you stop to read the directions. (Okay, I’m a guy... what did you expect?)

The better news is, the boxes are fairly inexpensive – right now, in the $50-60 range – and stores like Best Buy, Circuit City, Radio Shack, and WalMart have them on the shelves.

The best news... you can get up to two coupons from the federal government worth $40 each, so your final cost is only $10-20.

Take a minute and apply for your coupons here: https://www.dtv2009.gov. It takes about six weeks for them to show up in your mailbox... mine arrived two weeks ago. I applied for two coupons, and for some reason each coupon was mailed separately. Seems pretty inefficient, but maybe it’s just easier to do it that way.

The envelope stands out just enough from the credit card pitches that it didn’t get trashed, unopened, on arrival (we’re pretty brutal with junk mail). The coupon looks and works just like a gift card, and comes attached to a sheet listing a handful of stores in your area that sell eligible converter boxes. There’s also a flimsy sheet that lists manufacturers and model numbers of eligible converters.

Eligible? Why does that word keep popping up? What makes a converter eligible? A good question... for tomorrow. For now, I need to get back to my real job.

-- Jeff

DTV: First Things First

JH Engineering — Mon, 07 Apr 2008 16:10:00 GMT

Yesterday I told a friend about the pile of DTV converter boxes on my dining room table, and his face lit up with a look of eager excitement. “High def boxes, you mean?” No, I told him, DTV converters. “But DTV is high definition, isn’t it?” Not necessarily. “Oh. So... what is it really?”

That’s a very good question, and a good place to begin – before we start looking at the equipment, it makes sense to understand what digital TV is all about, so we know what the equipment is supposed to do. So first off, let’s clear up what we’re talking about:

Standard Definition, or SD, is the traditional television format we’ve been watching for the last 60+ years. All analog television is SD.

High Definition, or HD, has much more picture information than SD, so it shows far greater detail. It is also widescreen, which is what most people notice first.

“DTV” just stands for Digital TV. A DTV channel can carry HD, SD... or both at the same time. Over-the-air DTV is sometimes called ATSC, after the name of the committee that decided how the system should work.

“Okay, so DTV can be HD... but more? How does that work?” I’ve invited Claire, a regrettably hairless expert on such things, to help me illustrate:

All television channels use the same amount of space: you can fit one analog picture with sound into a channel, or the same channel can hold more than 19 million bits of digital data every second. Let’s build ourselves a new digital channel and see how it works...

All the open space between the white blocks is free for us to plug in whatever we want... so long as we can make it fit. But before adding any programming, we need to set aside a small amount of room for housekeeping information that tells your digital television what programming is in the channel, and how to play it... this information is called PSIP, and that’s the little pink block on the right. Now that the PSIP is there, your set’s electronic program guide will start working.

Nobody’s going to watch the program guide all day... we hope... so let’s put a real program in there. Let’s really splurge, and make it a high def program: the blue block network, perhaps:

Hmmm... that took up quite a bit of the channel, didn’t it? That’s one of the limitations we have to work around: one decently encoded HD program takes up more than half of a DTV channel.

See, there just isn’t enough room for another HD program. Sure, you could squeeze one of them way down to make it fit... but you’d just wind up with a rotten looking HD picture, which doesn’t make sense. So... instead, let’s fill the space with a SD program:

SD programs take up much less space, and we can fit an excellent HD program and a very good SD program together easily. In fact, we can add still another good quality SD program and completely fill the available space.

Remember at the beginning, when we said that DTV wasn’t necessarily high definition? We could use our single channel to broadcast four very good quality SD programs... and have a little space left over for other data (that’s the little yellow block next to the pink PSIP).

How do we keep all of these programs straight, and how do we identify them? Each program is called a “sub channel” – if the last picture is, say, channel 12 (I’m making one up, here), the red program would be channel 12.1, the yellow program would be channel 12.2, the white program would be channel 12.3, and the blue program would be channel 12.4.

So what does WSYR-DT look like right now?

Channel 9-1 is our main high definition ABC programming; channel 9-2 is standard definition VTV network, plus time-shifted news and other local programming.

It’s time for Claire to go back up to her box in the attic, so let’s wrap this up with the main points:

DTV is just how digital programs are delivered to your TV set;
DTV can be high definition, but doesn’t have to be;
One DTV channel often includes several programs.

It’s worth pointing out that even a standard definition program, transmitted digitally, looks far better than the same program transmitted with the old analog system. So what do we get with the switch to DTV? More programming choices free over the air... some in high definition... and far better pictures and sound for standard definition programs. Will it take some getting used to? Sure... but not a lot, and once you see it you won’t want to go back!

Now that we’ve gotten past all of that... on to the converter boxes!

-- Jeff

p.s.: For the curious, some of those Lego pieces are about 45 years old. It seemed fitting to use a prop dating back to the start of color television in Syracuse, to illustrate the transition to digital television now. Claire, the regrettably hairless expert, is my daughter’s far more recent addition...

What's all this DTV stuff, anyway?

JH Engineering — Fri, 04 Apr 2008 20:20:00 GMT

If you’ve been watching TV lately, you’ve seen them: graphics and messages warning that full power analog television is going away next year, and that you’ll have to do something about it before next February. So... what’s really going on, and what are your choices? How do you make the switch to digital TV without converting your living room into NASA control, with wires and boxes everywhere, and without taking a second mortgage on the house?

That’s what Plugged In is about: making sense of the new technology so you can make good decisions... and cutting through all the bad information that’s out there. As the February 2009 DTV transition approaches, we’ll be looking at the equipment that’s out there, how to hook it up, and how to solve the glitches that come up. It’s also a place where you can ask questions and get answers from someone who isn’t trying to sell you another gadget.

Most of our blogs come from the folks you see on the air – our reporters, Steve, Rick and Julie – so who’s behind this one? I’ve been an engineer at WSYR for more than 25 years, and spend most of my time designing, installing, and maintaining new systems... and for the last few years, that’s mostly been DTV. One reason you don’t see a photo of me (that’s your good fortune!) is that I’m generally well hidden behind cartons of parts, rolls of diagrams, technical manuals, and demos of new equipment. A single glance at my office will tell you three things: I love old maps of Central New York, I have a ridiculous number of projects going at any given moment, and I’m not Martha Stewart.

I’m also a Syracuse native... and like you, I’m coming to grips with changing over to a digital future at home. As I write this, there’s a stack of four different DTV converter boxes on my dining room table waiting to be tested. Next week we’ll start looking them over – and it’s going to be a real workout: my part of the city has always been a real challenge for TV reception.

Catch you next week!

-- Jeff