By Harry A. Jessell
TVNewsCheck, Sep 24 2009, 12:06 PM ET
Perhaps the biggest surprise of the DTV transition has been the poor performance of many VHF stations as digital-only stations. On the whole, their signals don't seem to reach as far or penetrate buildings as well as those of their UHF counterparts.
Since the June 12 analog cut-off, broadcast engineers at VHF stations have been trying to sort out the problems of digital Vs. And in this effort, they have had the support of consulting engineers, experts on the peculiar behavior of radio frequencies.
Among those deep into DTV is Richard Mertz, a principal with Cavell, Mertz & Associates.
In this interview with TVNewsCheck, Mertz says high-band VHF (channels 7-13) for fixed and mobile reception can be remedied with more transmission power, something that he hopes the FCC will consider granting. As for low-band VHF, his message is simple: Abandon all hope.
An edited transcript:
What's the problem with reception of digital VHF signals?
A lot of people don't want to install an outside antenna and, if you recall, the planning factors for DTV are based on a properly oriented, high-gain antenna mounted 30 feet in the air outside. Rabbit ears inside don't take into account the attenuation that the building materials in a home provides and or the reflective surfaces in a home that cause multipath.
I remember as a kid fighting with the rabbit ears and trying to tune in the station and you got an acceptable picture. Now with digital, you can't do that. Kind of getting the signal is not acceptable anymore. You won't get a picture with a ghost. You'll get nothing. I know from my own experience: A lot of people don't want to get up and move the rabbit ears around.
Another problem is the receivers. We have no receiver standards. We have decoding standards, but we don't have performance standards for the receiver. So depending on which receiver you have, you have different sensitivities, you have different abilities. Some of the decoder boxes can handle a severe amount of multipath; others cannot.
In some cases, in trying to get a good signal, people overdo it. I've been to several homes where people are complaining they can't get high-band VHF stations and the problem is they put an antenna amplifier between the antenna and the converter box. A lot of these amplifiers are noisy or they're overloading the front end of the converter boxes.
You mentioned high-band VHF. What about low-band VHF. Is that a particular problem?
We don't recommend using those channels. I know that several people have gone back to ch. 6, but I don't think that's a wise idea. There have been different studies done and papers published that talk about man-made noise, celestial noise in those frequencies.
So, if you're in the low V band, you should be thinking about getting out of there.
I don't think they should have gone there in the first place. It's spectrum the commission may recover eventually. I don't think it works very well. Propagation-wise, studies years ago suggested that high-band VHF was the best place to be and we tried to move people there as we saw fit.
What is the inherent problem with high-band VHF that makes it harder to receive?
This is a multifaceted problem, but it's basically power limitation, especially in the Northeast. You need more power to overcome building attenuation and get to indoor antennas.
The maximum power you're allowed in high-band VHF is 30 kilowatts at 305 meters of average terrain. The reason they did that was because they were working towards replication of the analog grades. Some of the planning factors may have been very conservative and didn't really take into effect how people actually watch TV over the air.
And an amplifier in the antenna line won't help?
Typically, you try not to have the amplifier. Let me give you an aside. We had a UHF LPTV client that was being picked up and carried by a local cable system, but the signal would drop out periodically. They had a dedicated antenna for this one low-power television station. I talked to them on the phone and discovered that the antenna was pointed in the wrong direction. Then, I asked if the signal passed through any amplifiers. Yes. Can you unplug the amplifier and bypass it? Can you plug the antenna directly into the receiver? We can. Do you have enough signal now? Oh, more than enough. They haven't had a drop-out since.
What is it that the amplifier does that causes the signal problems?
It can either overload the initial stages in the receiver or it can create noise that the receiver thinks is data because of the nature of the ATSC signal. So by taking the amplifier out you remove a variable that creates trouble.
If more power is the solution, how do broadcasters go about getting it?
We have been able to secure for several clients experimental authorization at higher power, but when you get an experimental authorization you're creating more than a half a percent new interference to other people and you have to demonstrate that you're not going to harm them. I've done measurements to show that our stations are not going to harm these other stations.
But you need a permanent solution. Would you like to see the FCC increase the power for VHF stations?
I would like to revisit the power caps, especially the Northeastern Zone One. I'm working with different groups to take the commission's temperature to see if it would entertain this at this time.
In your opinion, do you think you can jack up the power limits for everybody without causing a lot of interference among the stations in the band?
There's going to have to be a cooperative effort among all the broadcasters to increase power above the levels that they currently have. Everybody in high-band VHF is now seeing difficulties and they would like to overcome them.
We are close to having a mobile standard that's been created to piggyback on the ATSC signal. Is that going to work on the VHF channels?
It's going to have similar problems. With UHF the wavelengths are actually much smaller. Something like this [holds up a Blackberry] has an antenna that operates at 2 Ghz so the antenna's fairly small. At VHF frequencies, your antenna's got to be a quarter wave length. The middle of the band is about 15 inches. How do you fit that 15-inch antenna into here? That's part of the problem with using VHF for mobile. But I understand from some of my clients that they've seen demonstrations on mobile where it works just fine at V. I don't know how much of a problem it is. I'm only getting anecdotal information from clients.
Assuming that VHF mobile reception is a problem, how would you fix it?
Adding more power might be the answer. I don't know. More efficient antennas in the handheld devices might be the answer. You may have to put amplified antennas in there and then, of course, you have the inherent noise problems. So it's a multifaceted problem and I don't think that there's an easy answer to it yet.
What about the single-frequency networks and repeater stations. Is that something that broadcasters should be thinking about for VHF mobile broadcasting?
It depends on the terrain in your area. A single-frequency network using a series of smaller transmitters might be an answer. The commission's already authorized that. Given what limited information I have right now, I would like to see some terrain blockage between the main transmitter or central transmitter and some of these outlying transmitters to avoid interference.
Do TV broadcasters still care about their broadcast signals?
That depends on cable penetration. Where there's almost a 100 percent cable penetration I don't think they're so worried. The few off-the-air people that they have, they work with them and get it resolved. But in other areas where there's only 60 to 80 percent cable penetration, it's still important. And some markets where we work don't have direct satellite service yet. DirecTV and Dish don't carry the local signals.
Click RELATED for link to story
Personal note: I'm wondering now, although WLIO Channel 8 is enjoying great coverage with hardly any complaints, if we should not file for 60,000 watts, or more. After all, if this is going to be the norm, then, why not? I also wonder if we shouldn't ask the FCC to boost WOHL Channel 35 up from 9,000 watts to 20,000 watts.
I know I sound like a broken record, but the issue is not power, it's quality of signal.
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( 3 / 179 )I get one conversation, e-mail, or letter from frustrated people about the digital change every day. Sometimes they are cordial, other times they are very accusatory.
For the difficult people it comes down to calming them down, listening to their concerns, and then asking the right questions.
For example; most of the calls I'm still getting revolve around the Rabbit Ears antennas. Contrary to how much they cost, or what their claim is, they are a crappy antenna.
One fellow complained loudly and insisted that WLIO is operating with only a few watts of power. "Nobody can get you guys", he said. Of course we know this is not true as many people get us just fine, from Sidney to Bowling Green, and from Marion to Ft Wayne.
Statistically, WLIO has had the least amount of calls of all other stations I have polled. No where near the call volume of other markets the same size, and far less than the other stations in our corporate chain. But, we occasionally get calls.
As I said, some are cordial and just curious about why things work the way they do. Some are confused such as; "why is WOHL Fox now WLIO, and why is WLQP and WLMO now WOHL?" And just today I got an e-mail asking, "I noticed that WLMO CBS-38 is not on the air. Is it coming back?" The answer to this is a definite NO. Analog is gone. All our transmissions will be in digital.
More and more I'm finding that the rabbit ear antenna problem is intensifying, and stations are getting calls from viewers that say the signal drops out, or it's not there at all. I know WLS in Chicago has had to change channels because of the small antenna syndrome. Other stations that are high band VHF, or low channel UHF (14-30), are having problems. The rabbit ears will work to some extent on higher channels. But for lower channels they won't perform.
The only sane advice I can offer anyone with reception problems is;
1 - If you can, install a conventional antenna system with a Yagi VHF and screen-panel UHF antenna. Don't go on the cheap. Cheap antennas give cheap results. If you need some recommendations, contact me. There is some logic to "you get what you pay for".
2 - If you are using rabbit ears, or a flat panel/pancake antenna, or one of those halo antennas ... those are a compromise to a REAL antenna. You might be able to get some stations, but you'll never get as many or more stations than you would if you install a conventional antenna. And it's not the station's fault that you can't get reception.
3 - If you want help, calmly ask. If you want to vent, call your Congressman. All of us at WLIO can help if you a calm, civil, and willing to listen. We also have information we can send you, and know where to find resources if you need them. What we can't do is come to your home and fix your TV problems, buy you what you need, or stay on the phone if you want to yell or swear.
I say this because so often I get asked, "are you going to raise your power?" "When will you transmit better?" "How come you guys don't send your signal out this way?" In each case I have to ask, "why do you think it's us?"
When it comes to digital television, cooler heads have to prevail, and logic has to trump emotions. Once you loose your cool and toss accusations around, or allow yourself to be influenced by a disgruntled friend or co-worker, then you have no ability to resolve your reception problem.
Take for example the call I received today. Time-Warner cable had a massive outage in western Ohio. As I type this blog every one of the 100+ channels on TWC is frozen and there is no audio. However, I got a call from someone in the community, obviously frustrated. Give a listen.
Digital television is here and like CDs, unleaded gas, satellite radio, Twitter, and many new technologies, it takes a while to understand things. The one thing everyone must do is keep calm, ask questions, and listen to the voices of reason.
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( 3 / 172 )Several viewers have wanted some information on games and events on our station.
Please feel free to download these and pass on to your friends.
Notre Dame FB Schedule
Regular Season NFL
ABC NCAA College Football
NFL on CBS Football Schedule
World Series on Fox
NFL on Fox Football
2010 Winter Olympics on NBC
SEC on CBS
[ 2 comments ] ( 11 views ) | permalink |
( 3 / 146 )This story comes from California, but it could happen here in Ohio.
The Federal Communications Commission has issued a Citation to Irma Frausto of Compton, CA. Ms. Frausto was reportedly using a "Philips amplified television antenna, model Mant300, installed on top of a television set in the residence."
Apparently the amplifier had broken into self-oscillation on 840.356 MHz and the spur was strong enough to interfere with the input to a Verizon cell site. Since this was an unlicensed device, causing interference to a licensed service, the FCC was required to shut off Irma's antenna, as well as cite her for causing interference.
MY OPINION: Although I can understand the severity of interference of licensed services, and would not want to be on the receiving end of such a problem, I do find it odd that the government would cite her. However, this points out two things that viewers should keep in mind.
1). Some products on the market are absolute garbage, if not outright bogus. This includes the "amplified rabbit ears" that one area retailer is selling saying it receives stations from 50 miles away.
2). If it seems too good to be true, or you have no proof that it will work as advertised, may the buyer beware.
3). Sometimes the old folks had it right. A conventional outdoor antenna works wonders when installed correctly.
Click RELATED LINK below to see the legal filing from the FCC.
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( 3 / 170 )WOHL is presently on the air broadcasting ABC and CBS.
ABC is channel 35.1 and CBS is channel 35.2.
You may notice a few glitches in programming, but rest assured, we're working on all the issues. We're still in the middle of this move, and it might take a week or two to get things smoothed out. You never move into a new house and have everything the way you want it. :)
Below is a list of where our signal has been received. The number following the mileage is the number of different people whom have called from that community.
Lima. 91
Ada OH (16 miles) 11
Alger OH (16 miles) 5
Arlington OH (26.5 miles) 2
Ayersville OH (35.5 miles)
Beaverdam, OH (9.2 miles)
Benton Ridge OH (26 miles)
Bowling Green OH (54 miles) 3
Bluffton OH (16 miles) 4
Cairo OH (6.5 miles) 3
Celina OH (27 miles) 11
Columbus Grove (12.5) 5
Continental OH (28 miles)
Convoy, OH (33 miles)
Delphos OH (13 miles) 9
DeGraff OH (31.6 miles) 2
Deshler OH (38 miles) 2
Dola OH (22.2 miles) 2
Dunkirk OH (29.9 miles) 3
Findlay OH (33 miles) 11
Fort Loramie OH (29 miles) 5
Fort Recovery OH (39 miles) 2
Forest OH (32 miles) 2
Hamler OH (34.2 miles)
Harrod OH (10.4 miles) 2
Holgate OH (35.2 miles)
Jackson Center OH (18 miles) 2
Jenera, OH (23.2 miles)
Jay City (Celina) OH (31.6 miles)
Lafayette OH (9 miles) 6
Leipsic OH (25 miles) 2
Lakeview OH (15 miles) 5
Mendon OH (21.9 miles) 3
McGuffy OH (17 miles) 2
Maria Stein (30 miles) 2
Mc Comb OH (32 miles) 2
Mendon OH (20 miles)
Mt Cory OH (22 miles) 2
Middle Point OH (19.1 miles)
Miller City OH (24.6 miles)
Minster OH (25 miles) 4
Mt Blanchard (31.1 miles)
Nevada OH (52 miles) T (some signal breakup).
New Bremen OH (22 miles)
New Haven IN (52.5 miles)
New Hampshire OH (17.5)
Oakwood OH (29.7 miles)
Ohio City (26.4 miles) 2
Ottawa OH (21 miles) 9
Pandora OH (16.3 miles) 3
Rockford OH (28.1 miles)
Quincy OH (30 miles)
Rushsylvania OH (30.3 miles)
Sidney OH (31.3 miles) 2
Spencerville OH (14 miles) 8
St Marys OH (16 miles) 8
Van Wert OH (27 miles) 12
Wapakoneta OH (12 miles) 18
Waynesfield OH (13 miles) 3
Willshire, OH (35.6 miles)
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( 2.9 / 215 )We are still on track for the first day on the air being Monday (August 17th) at 7AM. Both ABC (35.1) and CBS (35.2) will be HD 720P format.
I'm still looking for reception reports. Please tell friends and family. Sunday will be the last day of testing. Starting Monday morning we will be into normal programming. What I need are
1 - Your address or neared major cross street (ie: 123 Main Street, Lima or something like corner of SR501 and Ft Amanda Rd)
2 - If you have a signal strength meter, can you give me a reading? Or, if it's just a graph, is it 8 out of 10 leds. How does it compare to other stations.
3 - What kind of antenna do you use? Rabbit ears, or roof-top antenna? Make and Model #?
4 - How are you getting us? Converter box, DishNetwork box, or Digital TV?
Any other thoughts would be welcomed.
Now, a few answers to questions.....
Fox (8.2) is in SD because that is what the network is sending us. We don't have a choice in that. However, we are sending out an HD signal in 720P format should they change their minds. That means that NBC, CBS, and ABC will be the only HD signals so far.
Several ham radio groups have asked for tours of the facility. We will be glad to host tours for groups, but we'll have to wait till the project is over. This could be October or November. After CBS and ABC are on the air, we have to build the new newsroom systems for digital, and move into the new computer room. Tours should be a minimum of 6 people. If possible, tours should be in the evening or weekends. We have a conference room if you have a club of less than 25 people that want to have a meeting.
We're also moving the ham repeaters, so some will be on and off depending on what we are doing. The D-STAR repeater has been moved (443.625) and is on the air.
Fred
[ 4 comments ] ( 35 views ) | permalink |
( 3 / 215 )
WLIO's engineering department is seeking reception reports from viewers of our new UHF Channel 35 digital transmitter.WOHL-DC UHF Channel 35 is operating with a power of 9,000 watts with an omni-directional antenna. The transmitter is located at 1424 Rice Avenue, on the west side of Lima, OH.
We are seeking the following information.
1) Your address, or nearest cross-street, and city.
2) How well is the signal received. If you have a signal meter, give us a reading such as 80% or 9 on a scale of 10.
3) How does the signal strength compare to other stations, including our own WLIO VHF Channel 8 digital.
4) A brief description of your antenna system. Rabbit ears, or do you have a tower? How high is the tower? What kind of antenna are you using?
5) How are you receiving us? On a converter, dish TV set-top box, or a digital TV set?
E-mail to fred@wlio.com or you can click the Contact Me link at the right to make a report.
Please pass this on to friends and family. I'm especially looking for reports in outside of Allen County.
[ 7 comments ] ( 113 views ) | permalink |
( 3 / 176 )WLIO will be conducting local HD tests (independent of NBC) with Cincinnati Bengal Football. The tests will originate on the following days.
August 14 @ 8:00PM - "Bengals at New Orleans"
August 20 @ 7:30PM - "Bengals at New England"
August 27 @ 7:30PM - "Bengals at St Louis"
September 3 @ 7:30PM - "Bengals at home hosting Indianapolis"
These transmissions will be made on WLIO-NBC on 8.1, as well as carried on cable. Note, at the present time Time-Warner cable is the only cable company carrying our HD signal.
If you would like to be our Signal Spotter, here is what I'm looking for.
1) A quality judgment on the HD signal.
2) A quality judgment on the audio.
Please let me know how you are receiving the signal and equipment being used.
In the event we have a technical issue, we will drop to SD. I'll try to post something here, but sometimes it's impossible to post when we're trying to solve an equipment problem at the same time.
Send reports to fred@wlio.com
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( 2.9 / 205 )Date: Thu, 30 Jul 2009 16:09:41 -0700 (PDT)
From: Steve Rich
Subject: WOHL-DC 35 >> Indy
To: fred@wlio.com
Hi Fred,
As a DTV DXer on the far north side of Indianapolis, near Carmel, I thought I'd let you know that your 9 kW WOHL-DC, with some tropo help, was really getting out late this morning (@ 119 miles). I captured two screenshots and have attached them. Just thought you'd enjoy knowing how far the new signal can go.
Plus, during the same time, WLIO-DT 8 was quite strong here, too.
Steve Rich
Indianapolis
[ 2 comments ] ( 134 views ) | permalink |
( 2.9 / 204 )by Bill Husted, Atlanta Journal-Constitution & Toledo Blade
It was just a short drive to a friend's house in another neighborhood, but it felt as if I was driving back in time.I spotted first one, then another and finally about four shiny aluminum rooftop antennas. It was like being back in the "Leave it to Beaver" days when almost every home had a sizable TV antenna on the roof.
Based on what I'm seeing and e-mails from readers, it seems the move to digital TV has sparked a minor resurgence of using an antenna to get free over-the-air TV. Some of you have cut the ties that bind to cable or satellite providers.
The fact that money is tight in many families probably gives this revival a bit of a boost.
There's nothing wrong with that. In fact, over-the-air HDTV actually can provide a better picture. All HDTV signals are compressed to some degree, but there's generally less compression used for over-the-air broadcasts.
Today we'll talk about antennas for the digital age. The first thing to know is that, despite what you frequently see in ads, there's no such thing as a digital antenna. No special antenna design or feature is needed to receive digital signals.
However, many people find they need a better antenna to pull in reliable over-the-air digital signals than they did before the switchover.
The best antennas for the digital era are large, designed for the frequencies you want to receive and put up as high as possible. Let's start by looking at each of those three criteria.
Bigger is better: While small rabbit ears may work, the bigger the antenna is (up to a point), the more signal it can grab.
Finding the frequencies: Broadcasters send out their signals on UHF and VHF (ultra high frequency and very high frequency). Some stations that used VHF in the analog days have moved to UHF with the digital switch. So an antenna made purely for VHF reception - and one that may have done just fine before - is not a good antenna for UHF signals.
Here in Atlanta, seven channels in my reception area use UHF, and three use VHF. You can check what broadcasters are doing in your area - and get a lot more information, including recommendations for the antenna you should use - at www.antennaweb.org.
Bottom line, whether you use rabbit ears or some giant eye in the sky, make sure your antenna is designed for both VHF and UHF signals.
High and mighty: At the frequencies TV broadcasters use, the signal basically follows line of sight. It doesn't bend very effectively around the curve of the earth, nor does it do a good job at penetrating huge masses such as hills or mountains. Putting the antenna as high as you can increases the number of stations it can receive.
While some antennas are designed to work in all directions, most large rooftop models are directional. In other words, they do best when turned toward the transmitting antenna. If your antenna is working well now, no need to mess with anything.
But if some stations seem weak, adding an antenna rotor can make a big difference. At the end of this column I'll list sources for both antennas and rotors.
I realize that in many homes, the idea of a huge mess of aluminum tubing will not be a welcome sight. In that case, consider installing an antenna in an attic, or use a smaller antenna that can be mounted under an eave. It will not be as efficient as a full-sized antenna up high, but it will beat the pants off the world's best rabbit ears.
Some of you will be lucky enough to get by with rabbit ears. Since my primary source of TV is cable, I only use my rabbit ears as a back-up to make sure that the Braves and other sports teams can continue to break my heart in case of a cable outage. I'm close enough to the transmitting antennas for the stations I watch to make that possible. The antenna Web site I mentioned earlier will tell you what you can expect based on your ZIP code or street address.
OK. I promised you some other Web sites:
www.rabbitears.info/market.php: A quirky Web site with lots of detailed station information.
www.channelmaster.com/category.php: My favorite source for antennas (both indoor and outdoor), signal amplifiers and rotors.
www.techhome.com: A source for finding professional antenna installers.
http://tinyurl.com/nl92v8: Antenna tips along with information on mounting an antenna in the attic.
Contact the author...
tecbud (at) bellsouth (dot) net
Bill Husted writes for The Atlanta Journal-Constitution.
Click the Related Link below for the original article
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