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Digital TV: Missed Signals

Kim Hart

Having trouble with your digital TV reception? Join the club.

After I wrote this story about the challenges some TV watchers are having in getting a reliable digital signal, I received dozens of emails from readers claiming they were experiencing similar problems. The main issue has to do with what's called the "digital cliff"--the digital picture is excellent until interference or a weak signal causes the picture to disappear altogether. Analog picture, in contrast, gets more snow or static as the signal weakens, but generally comes through in some form.

But consumers may also need a stronger antenna, which will probably need to be pointed directly at a broadcaster's transmission tower, in order to pick up a signal. And if you live more than 40 miles away from a tower, you could have trouble getting a signal at all.

One of the senior editors here at The Post tried hooking up a converter box to his TV at his home in Loudoun County. Even with a rooftop antenna pointing toward the downtown Washington towers, he can't receive three of the major network channels, and a fourth "crinkles" every now and then.

We're lucky in the Washington area, because the majority of broadcasters send their signals from a cluster of towers in the Northwest corner of the city. So most of the over-the-air viewers can point their antennas in that direction. But in other cities, the towers are more spread out, which means some consumers will have to point their antennas in different directions to pick up the signal they want.

Frustrations are flaring across the country. Harry Saal, who lives in Palo Alto, Calif., tried becoming an early adopter of the digital signals. While there are a lot of over-the-air digital stations in the Bay area, they broadcast from three different locations: some from San Francisco, some from East Bay and some from San Jose. He needed to get a directional antenna that could rotate between the stations. He also experienced disruption when planes took off and landed at nearby Palo Alto Airport.

"In order to to keep family harmony, my little 'experiment' didn't run very long," he said.

Melissa Dodworth of Boise, Idaho, wrote in an email that she has to adjust her rabbit-ear antenna every time she changes the channel.

"Feel like I'm back in the 50s, pre-remote, jumping up and down and going back and forth," she wrote.

Some readers, though, are finding better reception once they upgrade their antennas. Armen Gamble of Fairfax, Va., contacted us when she was frustrated that she couldn't get decent reception on the small TV she watches in her kitchen. She attached a different, more powerful antenna and got great results. "It's amazing," she said of the picture.

I visited a few people in their homes to make sure their reception problems weren't the result of human error in setting up the converter boxes. I visited Parker Nutall in Rockville, Md., and helped him hook a converter box up to the TV in his den. Luckily, it's wired to a rooftop antenna, so he got a great picture once we had the wires going to the right place. His second TV in the living room, however, relies on a set-top rabbit-ear antenna. Reception wasn't so great when we set the converter box up with that one.

Judging by the amount of feedback I've gotten from this story, it seems like a widespread issue--and one that's causing a lot of frustration from TV-loving folks. The transition to digital technology has been billed as a chance for the broadcasting industry to regain viewers who abandoned over-the-air broadcasters years ago for cable and satellite services. But glitchy reception could undermine those expectations.

There will certainly be more to say about this issue as we approach the Feb. 17 deadline. A GAO report found additional hurdles facing broadcasters as they prepare for the transition. Rep. John Dingell (D-Mich.) has announced that he will hold a hearing on the matter June 10.

I'll keep you posted. So stay tuned to the blog, especially if it's just too annoying to tune into your television.

By Kim Hart  |  May 22, 2008; 11:10 AM ET  | Category:  Kim Hart
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I live in Western loudoun County and I was able to get most, if not all, of the digital/HD feeds of the DC networks on a set of 15 year old rabbit ears. I upgraded to a $100 Radio Shack antenna that I put in the attic and now I can get all of the DC stations (and about 20 PBS channels)and several of the Baltimore networks. You need an antenna that picks up VHF and UHF and you need to aim it in the correct direction.

Posted by: bob | May 22, 2008 3:33 PM

I am some 30+ miles south of Dallas. I had to put up an antenna in the attic to receive the analog stations, however I still couldn't get them all.
When I put in the digital converter, I got channel #2 which I didn't know existed before and channel #4 comes in much better digitally than it did analog. Some of the UHF stations are not quite as good with the digital as with the analog.
So, it is a mixed blessing but overall, I have been very pleased with the digital channels here in the Dallas area.
I got two coupons and bought one Zenith at Radio Shack and one RCA at WalMart. The Zenith is more sensitive than the RCA, picking up more stations. The RCA is more flexible in the ability to program it to control the TV to which the converter is connected. I also have DirecTV with RCA receivers and the problem with the RCA digital converter remote control is that both the digital converter and the satellite box use the same coding so if I change channels on one, the other also reacts.
I enjoy your columns, Regards,
Hal

Posted by: Hal in Waxahachie, TX | May 22, 2008 3:50 PM

There are many converter boxes on the market, with more coming. As with any new technology, their quality, efficiency and price vary considerably. So the selection of a converter box will be an important variable to desired digital reception.

But an even larger variable is the choice of the right antenna.

Most TV consumers think of antennas as low-tech devices, but there is more behind some of the newer antenna designs than just bent metal and plastic. Many of the TV antenna designs on the market today, such as the Yagi and rabbit ears have technology roots going back 30 to 50 years or more.

The switch to digital broadcasts however is bringing consumers back to Off-Air reception and the increasing sales are providing the motivation and investments necessary to develop new models and new technology. The fact that most designs on the market now were developed prior to the advent of much of the computer technology, software and algorithms in common use today, left open numerous avenues to improve upon tried and true designs and develop new ones. Additionally, recent regulations and standards are opening new doors for antenna engineers to develop smaller antennas with improved performance and aesthetics.

The correct digital antenna, installed and aimed properly (considering obstructions)with a wide enough "beam width" (search area) will receive desired local stations it's aimed at up to 70 miles or more, including multi-cast programming and several in HD, almost completely uncompressed, not available from cable or satellite. Some viewers may even be able to receive some or all of available out-of-town channels, carrying blacked out sports programs or network broadcasts not available in home towns.

As an added benefit, an OTA antenna provides reception for second sets in homes not wired for whole-house signal distribution.

While cable and satellite program providers will continue to serve the great majority of homes as the primary signal source, missing HD local reception, compression issues, higher costs, billing add-ons, service outages, contact difficulties, in-home service waits and no shows have left many of these subscribers looking to OTA antennas as alternatives and backup.

Depending on the level of desire to receive an excellent digital picture and multiple broadcast signals, considering the investment in TV entertainment already made by many viewers, they should consider up-grading to a new Digital Off-Air indoor or outdoor antenna.

Posted by: antennaguy | May 22, 2008 5:08 PM

Its actually not that complicated. Most digital signals are on the UHF band and as such are line of sight.

Indoor "rabbit ear" type of antennas typically have poor performance on the UHF band and being indoors they suffer from the attenuation from building materials. To make matters worse, many indoor antennas are burdened with cheap & noisy amplifiers which only make the job of the digital tuner that much harder.

Obviously there will be some people able to use rabbit ears (or a coathanger for that matter) but they will be the exception to the rule.

I have tried numerous designs , and I've had the best results with a NON-amplified DB4 UHF antenna mouted on my roof. I get reliable reception at over 40 miles from the transmitters. Its not rocket science, you just need to get additional elevation on your antenna, and remember outdoor installations will work better than indoors & DTV channels will be on higher frequencies, so invest in an antenna that focuses on the core DTV frequencies. (174-216 MHz & 470-698 MHz)

The good news is, the newer designs are much smaller, so an outdoor antenna won't be very noticable from the ground.

If you must use an amplifier make sure is is a low noise design. When it comes to DTV reception, the noise factor is far more important than raw gain.

Posted by: rich644 | May 22, 2008 7:09 PM

Having a Sony LCD with a built in tuner, I had a lot of problems with a Radio Shack indoor antenna, I'm only about 12 miles from the transmitters in KC, but I only received about 3 digital stations out of about 10 in my area. I then bought a Terk TV55 and gained an additional 2 stations

The Antennas Direct DB2 in the attic was a night and day difference, locking in all 10 stations with only one channel below 90%.

I would suggest avoiding combination VHF antennas, stick to UHF only. Trying to force an antenna to cover all bands results in compromises on the UHF side and will also deliver unwanted signals and interference to your tuner. UHF antennas are also smaller.

Posted by: jwalter | May 22, 2008 10:12 PM

In reading the comments I find some not to be quite accurate and others close.

First not all areas in the US will be UHF only, but will be a combination of UHF and VHF digital (DTV) stations. In Las Vegas for instance we have DTV that starts on Low band VHF on channel 2 and then goes through High band VHF channels 7 through 13 all the way to UHF to channel 40. The majority of these DTV signals are on channels 7 through 12 (later 12 will be 13 after the transition). So a UHF only antenna will not work in this area (Direct TV uses a UHF antenna due to this misconception and every one that has this type of installation ends up with reception trouble especially for the low band VHF channel).

The other parts are true, like the public in general is totally unaware of what is happening. There will also be a serious problem for those that receive stations from different directions as well as those that the stations will either be flash cutting to their same analog channel or changing channels just before or on the transition date.

The issue here is that the channel the station is acutally on is a virtual channel and the real channel is unknown to the public. The public only knows the analog channel since the virtual channel is listed as the same as the analog channel, but with sub numbers like dot-1, dot-2, etc., or dash-1, dash-2, etc. They will not know what channel the dash or dot channels are actually being broadcast on and this information is not actually broadcast or transmitted for the public to actually know about.

Because of this virtual channel issue they will need to scan for channels to allow the set or convertor box to find them. The problem with this scanning for channels is that the channel might be missed during a scan due to a reception anomally (air plane flutter or marginal reception near to the cliff effect) or once found forgotten during a rescan, since all the stations weren't found because they are in a different direction. This rescan looses the channels that were found the first time and only then has the new channels found. Without actuslly knowing what the real channel is and only knowing the virtual channel, one can't find the station.

For instance, KABC in Los Angeles is on analog channel 7 but the virtual channel for the DTV signal is actually on channel 53 (7.1 or 7-1, for instance) and is not on channel 7. This DTV channel will change on the transition from channel 53 to channel 7, since they will be flash cutting from the one to the other on the transition date.

Since the public has no clue of where this virtual channel is actually located as far as the real channel is concerned, when KABC transitions on February 17th 2009 and analog channel 7 as well as their present DTV channel 53 goes dark and KABC then pops up on channel 7 as a digital signal instead of the analog signal, the public will think that the station is now no longer on the air since their TV or convertor will not know about this new virtual channel.

Since the perception by the public due to this change is that the station is now dark or off the air, the station will be inundated by calls from upset and angry viewers who are wondering what happened to the station and who have been trying to figure out what happened and are then trying to find them.

Now lately here in Las Vegas channel 3 (the NBC affiliate) did a test to see how things might work on the transition by simulating the analog shutoff. They did this simulation during their newscasts from morning to late night on a well announced day. During the actual simulation they had a full runing dialog of what they were doing and then during the dialog they "pulled the plug on analog". The "pulling the plug" put up a simulation of nothing (snow or no reception) on the air. A little after the snow and noise came on the air on the analog side from a video tape feed that they switched on air on the analog broadcast side only, they overlaid a message stating that if you are seeing this message instead for the normal newscast of this that you need to call or visit a WEB site on what to do in order to be prepared for the digital transition.

The station had caller overload from this simulation.

Based on this small test the general public is really not aware of what is to happen nor are they really prepared.

For those that have the needed equipment and have an outside antenna of the proper type and correctly aligned there is still issues with reception.

This issue of reception was shown at the local FOX affiliate, TV5, at their broadcast studio facility. This facility is located within 5 miles of the main transmission site.

The transmission site is located on Black Mountain in Henderson Nevada which located in the same town that TV5 has their studio but is only 5 miles away from each other. This studio location was where the test was performed.

During the test they found that from that studio site even with the right type of antenna (and they tried low gain as well as high gain, cut to channel as well as broadband) and while moving the antenna to different heights they always received very good signal levels from all the stations that were broadcasting in digital. Even with all of this changing and manipulating the antenna they could not receive some of the stations reliably.

All stations in the VHF band, both low and high band, are at full power as are some of the UHF stations. Yet due to certain types of self interferance, namely multipath from front side of the mountain due to signal bounce of the direct signal from the transmit to the receive location, that the signal gets distorted from the combining of these signals at a distance. This combining of this reflected signal and the main signal actually causes partial to full cancellation of the signal which regardless of the signal strength makes the digital signal non receivable.

No antenna, special or otherwise, nor placed at any reasonable height would correct the reception problem in this case. The only way the problem of reception could be actually cured was the re-locating of the receive antenna to another location a few blocks away. This would not be a solution for the typical home viewer and because they now can't get reception of their station would cause bad fellings at best.

The only other solution would be to dramatically change the type and location of the transmission antenna.

So, to that, I agree that all is not ready or well for the transition to digital broadcasting. Just as those who use cell phones know that when they work they work well and when they don't they are saying "Can You Hear Me Now?"

This last statement, slightly modified, may be what the broadcaster will be saying and that is, "Can You See Me Now?"

Posted by: TV RF Engineer in Las Vegas | May 24, 2008 12:44 AM

Excellent comments by several posters...

I have a few additional ones:

There is certaihnly confusion regarding the term "digital transition!" In some instances it almost seems as if there is a suggestion that at midnight Feb 17th 2009, there is going to be a large switch falling from the sky that will turn off the analog transmitters while simultaneously turning on the digital transmitters! The more appropriate "analog shutdown" label has been buried in the noise of the more appealing high-tech monicker.

I have personally dealt with cable subscribers who used a digital TV for
over a year without being aware of the capabilities of the set with a small off-air antenna. They were totally amazed that for the investment of a few dollars they were able to watch off-air HD after doing a scan!

Not enough emphasis is being made by stations that DIGITAL IS HAPPENING NOW!

Digital converter boxes can be hooked up NOW! No need to wait for that "switch" to fall from the sky!

Regarding antennas: HOA's are still telling their members that off-air antennas are not allowed, despite the fact that DirecTV and DishNetwork antennas, which are covered under the same rules,
are hanging all over buildings and homes.

In a lot of cases, those dish antennas are placed in what would be considered a restricted location... i.e. not under direct control of the owner or renter.

The latest FCC rules for placement of satellite and off-air antennas. for renters and property owners. can be found at:

http://www.fcc.gov/mb/facts/otard.html

Another fact that is not mentioned is that
digital signals do not require a "special" antenna. All that is needed is something that works. It could be that "old"
off-air antenna. Hook it up and see what happens. It may be time for your "local antenna company" to reappear for those challenging locations.

Posted by: Southeast RF Guy | May 24, 2008 10:56 AM

1) On top of the TV is one of the worst places to put an antenna, especially an old CRT TV. The RF noise they put out can really hamper reception. Move it to a window sill at least.

2) If your house has stucco or any other type of metal siding, forget about an indoor antenna. The mesh in stucco acts as a Faraday Cage, which greatly reduces signals. An attic antenna may be a possibility, if the stucco doesn't go all the way up, or if you can point the antenna through the roof instead (still far from ideal, however).

3) Small frequency changes for some stations is an understatement. e.g. WMAR in Baltimore is on 2 (54-60MHz) for analog, 52 currently for DTV (698-704) and will be moving to 38 (614-620) next year.

4) The 40 or so Low-VHF stations will be very difficult to receive with an indoor antenna. Chicago's WBBM has been a nightmare on 3, but they are moving to 12 next year. When WPVI in Philadelphia moves back to 6 next year (from DTV 64), it could be a significant problem.

As others have suggested, try out your DTV reception now.

Posted by: Mike M | May 25, 2008 10:40 AM

I found I cannot get WMPT or WHUT at all but I get all the WETA channels. Not progress at all....

Posted by: L | May 28, 2008 7:11 AM

I have two converter boxes and could not get either of them hooked up, and working, the way they "should" be hooked up. I have asked at several stores what I need to buy in order to get them installed properly, and working the way that I want, and have gotten different answers at each place but no solutions. Both of the converters are packed up in their boxes and shall remain so until next February or until I feel like wasting a few more hours in an exercise in frustration.

Posted by: No HD in Bethesda | May 29, 2008 9:46 AM

Wow, this new/old digital television is just great. I'm here at the Eastern Shore where we've never had anything but snow reception, if you are lucky to get any signal OTA at all.
I'm loving this not having to pay for simple tv reception. I'm so excited to finally get free tv. And 9 channels w/o even trying. I can barely wait 'til my rotor gets here. Before getting my digital converter box for less than 10 bucks (after the government's coupon - thank you very much Dept. of Commerce) and the new digital roof antenna for under a 100 bucks - I only received CBS, ABC, & MPT, depending on the weather and the only one with fairly good picture was CBS. This is great and the way TV used to be before the crooks arrived in town. I hope this new/old TV puts them out of business. Or at least reduces them to being internet providers only. Good riddance. If you think about it, those who are paying to watch TV are actually paying to be bombarded with commercial advertisements. It's sickeningly criminal I tell you!!

Posted by: SuzyQ | May 30, 2008 2:51 PM

Why are we futzing with "signals" when an unlimited high definition stream can be delivered on demand to any audience using broadband? I can watch shows when I want on Hulu.com and then can be as defined as my ISP (Clearwire) and PC allow.

Posted by: John Bailo | May 31, 2008 12:58 PM

We have an older RCA TV with a roof antenna, and do not have cable, so we purchased a Zenith converter box. Zenith was the only one available at the retailer. Instructions for the converter box was to set the tuner to Channel 3. We also have a separate VCR player/recorder with remote, and a separate DVD player/recorder with a remote. Before the converter box, in order to use the VCR we had to put the TV remote to channel 3, and in order to use the DVD, we have to put the TV remote on input.
After setting up everything for the converter box, we couldn't get ABC (our channel 30) that we always had before, so we had to buy a 5-foot pole to lengthen our roof antenna to 10 feet in order to be able to view ABC.

When we went to set the timer on the VCR recorder to record a program, it only recorded gobble-de-gook. It recorded from the channel that we had chosen (channel 5) on the VCR menu. We could only record if we were watching the program, or had not changed the channel on the converter remote.

Which means: only 1 timed program can be set to record at a time, and we must leave it on the channel we selected to record from. Which means we cannot record a channel while watching another channel, or set the time-record to record different channels while we are gone. This was not the case before. When we called the toll-free # from the instruction manual, we were told we would have to purchase some kind of receiver to hook up to in order to be able to set numerous timed programs to record. This is ridiculous! Now we have 4 remotes and probably will have to buy another contraption with another remote that will probably get lost and/or confused with the others.

Why did they not explain how all this would work together, or NOT WORK TOGETHER, before they told us we will have no choice and must do as we are told, or we will be out of luck television-wise?

Posted by: Jeanette | May 31, 2008 10:56 PM

We bought our converters and tried one. Some of the stations the pictures kept fading out. I understand this might be the reception. Also we could not get channel 10 or 12. Does that mean they are not digtal right now? Will we be able to receive those stations once everyone goes digital?

Posted by: Kathy Seyller | June 5, 2008 10:58 AM

I wonder why "the feds" aren't discounting or giving away coupons for roof antennas?

They are doing it for the converter boxes which cost half as much but, correct me if I'm wrong, isn't it necessary to have both to receive the TV frequencies/signals?

In response to John Bailo, why would anyone want to pay for TV when you can get it free? Am I missing something? I mean, how much technology is too much?

The 9 digital channels that I now receive with my new converter box + roof antenna are excellent and it doesn't take forever to figure out that there's nothing worth wasting my time watching, either.

Everyone around me here at the beach pays for gazillions of channels filled with commercial advertisements and complain that there's nothing on! Wow, how much sense does this make? I'll answer that, absolutely none. We've lost our minds, people. Then, these same people end up going out to the movie rental place and renting movies. How much entertainment do we need? We've lost our way. What happen to reading a good novel in peace and quiet?

Posted by: Suzy Q. | June 9, 2008 12:14 PM

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