Iowa Public Television

Monday, March 31, 2008

Enhanced IPTV-Digital Services!

Good news for over-the-air IPTV-Digital viewers!


In response to viewer requests, IPTV now has three digital channels on the air for over-the-air viewers.


11.1 - IPTV-Digital

IPTV-Digital is IPTV’s primary digital channel and is broadcast on the .1 channel (11.1 in central Iowa; 12.1 in eastern Iowa; etc). It features programming that showcases high-definition and other digital programming options. IPTV-Digital first began broadcast in August 2001, and now offers local and national digital programming to Iowans across the state. IPTV-Digital is also carried by many cable and satellite services around the state. Viewers watching via cable or satellite need to check with their providers for channel numbers.

11.2 - IPTV's Analog Simulcast

IPTV’s analog schedule is now being simulcast on the .2 channel. It features our regular schedule around the clock, including PBS Kids programming weekdays from 6:30 a.m. until 5:30 p.m.

11.3 - IPTV-Plus

IPTV-Plus can now be found on the .3 channel. Previously it was carried on the .2 channel. On this channel, viewers can watch outstanding how-to programming each day with IPTV Create programs. Monday - Thursdays from 7 - 10 p.m., viewers will have the opportunity to see what potential multicast channels may have to offer in the future.

Both the .2 and the .3 channels are only available to viewers who utilize an antenna with a digital television set or an older set connected to a converter box.

41 comments:

Anonymous said...

I recently purchased a small DTV for use in my kitchen. Since I live in the country and do not have access to cable TV, I use an antenna that has long provided good reception on 4 channels in central Iowa.

So far my experience with DTV has been very disappointing. While the analog channels produce a clear and reliable picture, the digital channels are plagued by frequent annoying picture break-up that soon sends me back to the analog channels. If this is what on-air DTV is going to be like, then it looks like a great scheme to pressure everyone into paying for cable or satellite TV. Can you offer any advice on how to get a better DTV picture using an antenna, or am I going to be stuck paying for 100 satellite channels that I don't want just to get IPTV ?

Bill Hayes said...

In order to respond to your comment with certainty, I would need to know a little more about your location and antenna. However, based on your statement that you use "an antenna that has long provided good reception on 4 channels in central Iowa," I can make a couple of educated guesses.

First, I am guessing that the four channels your are watching are WOI-TV on channel 5, KCCI on channel 8, WHO-TV on channel 13 and Iowa Public Television on channel 11. If this is the case, it is possible that you are using an antenna that is designed for VHF television channels only which would be channels 2 through 13. As confusing as this may sound, even though our digital service and the digital services of the other station identify themselves as being on channel 11.1 or 8.1 or 13.1 or 5.1, the DTV tuner is actually receiving the digital signals from different channels. In the case of these four channels, WOI-TV's digital service is actually on channel 59. KCCI's digital service is actually on channel 31. WHO-TV's digital service is on channel 19. Iowa Public Television's digital service is on channel 50. All of these channels are UHF and if your antenna is VHF only, it would not receive a very good signal. So that is possibly the problem. A quick way to test this would be to try and watch some of the UHF analog channels that are on the air. KDSM is on channel 17 for their analog service and channel 16 for their digital service. I would suggest trying to tune to channel 17 and see if you receive their analog picture as good as the other four station's analog picture. If not, then the problem is most likely the antenna.

If it turns out that it is the antenna, a good long term fix would be to replace the antenna with one that does both VHF and UHF channels. Another option would be to watch the analog service until it is turned off in February of next year because all four of the VHF stations will be moving their digital service from their UHF channels back to their VHF channels and if your antenna is working well with our analog VHF services, it should work well with our digital VHF services.

If it isn't the antenna, please provide some more information regarding your location and I can try and help determine what the problem might be.

Bill

Anonymous said...

Bill, thanks very much for responding to my questions about digital TV reception problems. Only public TV would offer that kind of service.

Regarding our digital TV reception problem, I cannot say whether or not our antenna was specifically designed for UHF reception, but we seem to receive the FOX channel(17) just as well as the 4 others, so the antenna must have some UHF reception capability.

Our digital reception seems to consistently be worst for the digital versions of channels 8 and 11, and somewhat better for 5 and 13. Some evenings are better than others however, so weather or some other variable seems to be playing a role in signal reception.

I live a few miles north of Ames, and about a mile west of the small town of Gilbert.

Anonymous said...

More then likely you will need to put up a outside antenna if are using rabbit ears or a UHF loop antenna. Digital is a more of a all or nothing type of signal were as analog is more forgiving. With analog you may get some "snow" where digital you get a blocky picure.

I for one may have to get two antennas since I get some channels from the south of me and other from the west.

Anonymous said...

So far I'm am VERY dissapointed with the "better" DTV. I can go from having a good signal of say 8 out of 10 to the next second having maybe 3 out of 10.

Ken said...

I connected a DTV converter box to our TV and do not get IPTV now. I do receive channels 3 and 15 however we watch very little of these channels. Looking at the IPTV coverage map for DTV there is no Digital signal being broadcast in southeast Iowa at this time. I live 3 miles west of Fairfield. When will IPTV be broadcasting a digital signal to Southeast Iowa? Where is the transmitter going to be?

Bill Hayes said...

Hi Ken,

You live in an area of Iowa that is promarily covered by translator services rather than full powered television stations although as you point out, you do receive digital services from the two full powered stations that are in the area. The rest of the television stations in that area use translators which are low powered television transmitters designed to receive the primary station's signal and rebroadcast it on another channel, thus the name translator.

There are a couple of issues that you have discovered. First, is that although all full powered television stations have by federal mandate begun transmitting digital television, the Federal Communications Commission did not create a similar mandate for translators so as a result they do not have a companion digital service on the air and at this time have no requirement to broadcast digital television. For our part, Iowa Public Television is rebuilding all of our translator stations (we have a total of 8) and we will convert those stations to digital operation around the same time that we switch off our analog service. At that point you will receive all of the DTV services that are broadcasted on our full powered digital transmitters.

The other issue you have discovered is that the DTV converter box only receives digital signals and not analog. As a result, the only channels your converter box finds are the digital ones. To further compound the issue, very few of the converter boxes on the market have a very basic feature called antenna pass-through. What pass-through does is allows the antenna signal to continue through to your television when the converter box is turned off. This is a real problem as long as there are a mixture of analog and digital services available. If the converter box has pass-through, when you shut it off, your old analog television tuner would still receive service from the translators and you would tune to them the way you always have. If pass through isn't available, you actually have to reconnect the antenna to the analog television to receive the analog service.

As soon as we discovered this problem, we added a third service to our digital output which is the same service that we broadcast on our analog channel. This allows people that receive out digital service to get all of our services without having to diconnect their converter boxes. Unfortunately in your area, digital services from IPTV will not be available until February of next year and I do not know what the plans are for the other translators that carry the other Des Moines stations are.

I can tell you that a number of the manufacturers of the converter boxes are releasing updated versions that offer pass-through but I do not know what their policies are for returning units. I would check with the store that you purchased the converter box from to see.

Anonymous said...

Why did you use sub-channel 2 for simocast instead of sub-channel 1? Most published schedules are for simocast.

Anonymous said...

Why does the audio level vary on your digital broadcasts? The volume raises and lowers every few minutes on channels 12.x and 32.x. This is indeed annoying!

Jennifer Konfrst said...

Re: Audio Levels. Below is a note from John Stone in IPTV's engineering department regarding audio and our digital services.
***
Do the other stations have varying audio also? If you listen to our channels at 9 AM or 3 PM does that audio not match the picture? There is a Second Audio Program function (SAP) on all sets now that allows stations to put on different audio than what is normally with the picture. We are the only ones on Iowa that I know of that offer this service to our viewers. When there is no special audio to put on, we usually put our normal audio on.

There is also a sound function on your set that controls loudness of the audio (supposedly automatically) that you might check or even disable to see if that fixes the problem.

If you need more help, please call 800-532-1290 and ask for me and I will try to help.

Thank you,
John Stone
IPTV Engineering

Bill Hayes said...

I am sorry that the comment about being "VERY dissapointed with the 'better' DTV" does not have more information. If you would or anyone reading this blog would like our help in solving the problem, we really need more information to analyze the problem and suggest a solution. Since I have no real data to work with I'm afraid there is little I can do. I can tell you that you are in a very small minority of people and that the vast majority of our viewers are thrilled with the quality of our content and the additional service we provide.

I am uncertain about your statement "I can go from having a good signal of say 8 out of 10 to the next second having maybe 3 out of 10." If you are talking about signal strength, it sounds like you are using an indoor antenna and I will be writing a brief blog about the problems with indoor reception in the next few days which may help.

If you want to respond with more detail, I can probably offer some guidance for corrective actions.

Bill

Anonymous said...

Hello Bill, I too have been having some picture and sound break up using a 10 year old VHF/UHF antenna that is mounted in my attic. Today is Saturday, June 7th at 3:30 pm and it is very windy here in Urbandale. My Digital TV has a digital signal strength indicator with ten bars. Channel 5.1 signal strength is variable. With 2-5 bars, the picture and sound break up. With 6-8 bars the picture and sound are fine. Ch 8.1 (High Def Golf) is acting the same as 5.1. Ch 11.1 is fine at 8-10 bars. Ch 13.1 (High Def Gymnastics) is fine at a constant signal strength of 10. I rarely have any signal problems with 13.1, usually have problems with 5.1 and 8.1 and occasionally have problems with 11.1 Until the stations all go back to VHF frequencies in Feb 2009, do you think I need to move the UHF portion of the antenna to improve the signal strength of channels 5.1, 8.1 and 11.1?

Bill Hayes said...

The reception issue in Urbandale raises some interesting issues. Urbandale is only about 15 miles from the DTV transmitters for most of the Des Moines station and as a result should have excellent reception. Your description of the signal meter showing signal level fluxuation seems to indicate that something between the transmitter and receivers is moving in the wind. It could be large trees to the north of the house moving in the wind. One thing you could try is a fairly low gain (12 dB) preamplifier mounted at the antenna to overcome the loss of signal strength caused by the roof of the house and the cable run down to the television. Bill

Anonymous said...

I live in West Ames and have been having similar problems to some viewers, i.e. weak signal with indoor antenna. I then purchased a good outdoor Terk antenna that has an amplifier built in. Now I get good signals (minus bad weather days) except for Channel 23. What else can I do to get Channel 23?

Bill Hayes said...

I am not sure what the issue would be on channel 23 (KCWI) reception in west Ames. Especially since the station is licensed to Ames, IA and their signal originates from the same tower as our digital signal. I am not sure from your comments if you are talking about digital or analog service reception. If you are talking analog, then KDIN, KCCI, WHO and WOI are all VHF stations and the remainder of the services are UHF and there are differences in the how these signals travel through the air and how well antennas work with them but you are so close I wouldn't expect a significant amount of difference. Can you provide me with a model number for the Terk antenna you are using and a description of where it is mounted on the house?

Bill

Anonymous said...

Hi Bill,
I was referring to the digital channels. I have the Terk HDTV Antenna Amplified as seen on Amazon here http://www.amazon.com/Terk-HDTVO-HDtv-Antenna-Amplified/dp/B0009W9WHQ/ref=pd_bbs_sr_1?ie=UTF8&s=electronics&qid=1214846211&sr=8-1

It's installed outdoors on the wall of our garage. I know my husband pointed it in the general direction of all the stations and I think the stations are all in the similar direction. But Channel 23 (also channel 34 and 56 which we're not concerned about) just won't come in. Like I mentioned in my previous post, after using the compass and measuring the general direction, this new outdoor antenna has gotten us very good signals compared to our indoor rabbit ears. But Channel 23 remains elusive. Many times it won't even register on the List of Channels. When I rescan for channels and do get it, it's just a blank channel. Thanks for helping!

Anonymous said...

There was an article on Mar 31 "Enhanced IPTV Digital Services".
Comment #11 from Bill Hayes, on May 21, said he would be writing an article on problems with indoor antenna reception.
When can we expect this to be posted? Anxiously waiting for this.

Bill Hayes said...

I haven't forgotten about the promised article on indoor reception. I have been working on it for a while. I have had some trouble getting some necessary antenna information on some of the indoor antennas that are available. I should have it done as a new post in a couple of weeks if a few of the antenna vendors come through on their promises.

Bill

Anonymous said...

I wrote the question on July 7
about indoor antennas. When you post the article, please include
your opinion on the Winegard SS-3000 Sharpshooter indoor antenna.
This looks like a very good unit, if it lives up to the advertising!

Anonymous said...

Hi Bill,

I was wondering if you had anymore advice about reception for Channel 23 (digital) in West Ames? Also, are there any reviews for the latest models of converter boxes? Would there be any difference in quality of reception from one model to another?
Thanks!

Anonymous said...

Why is the digital signal so affected by bad weather? Is this what we are to expect after the switch over? On Sunday, July 27, we could watch all the analog channels, but only digital channel 56. This was the case for most of the day, whether it was actually raining or not. I too am disappointed by what I have seen from this switch. (I have an outdoor antenna that is mounted in my attic.)

Bill Hayes said...

At least part of the problem on July 27th was the fact that we lost all power at the DTV transmitter site and we don't have a generator there. We also lost power at the analog site but two different power companies are involved and power at one site doesn't alway mean power at the other. The problem for IPTV was further magnified by the fact that when power was restored, it was done in such a manner that it burnt out the microwave that we use to relay the digital service from our analog site to our digital site and it took us some time to find and fix the problem.

Bill

Anonymous said...

Does changing the angle of the roof mounted antenna help?

We live in Eldora. Our new receiver picks up the major Des Moines stations, but not IPTV.

Where would we best receive signal from?

Thank you,
Roger

Bill Hayes said...

Hi Eldora,

I am somewhat perplexed that you would receive digital service from the other Des Moines stations and not us since all of the digital services are coming from the same area. One thing to try would be to directly enter the actual RF channel for IPTV's digital service which is UHF channel 50. You could then turn on the signal strength meter on the receiver and see how much signal you are getting from our transmitter.

Bill

Anonymous said...

I too live in Ames and can not get 23. According to wikipedia kcwi is not broadcasting digital but still doing analog until feb.

Bill Hayes said...

KCWI, channel 23 currently operates only an analog television service. When they were granted their license there were too late to get a companion digital channel. As a result, they will flash cut on channel 23 from analog and stay on channel 23. It will be necessary for you to rescan your digital tuner to find their service.

Bill

Alicia Wilson said...

I am experiencing a problem with receiving the digital channels. I am in the Ottumwa area and I receive 15.1 only. I am worried about this as I will not be able to get nay of the channels I have always gotten anymore. This will include IPTV which my three year old loves. I am unable to get cable with local channels as the local tv stations have a block on our area. Is there any advise that you can give me.

Bill Hayes said...

Hi Alicia,

Ottumwa is one of the areas in Iowa that is serviced by translators as well as a couple of full-power television stations. A translator is a low powered television station that receives the signal from a full powered television station and rebroadcasts the programming on another channel. In your area, we have a translator that receives our service on channel 12 out of Iowa City and rebroadcasts it on channel 18.

Unlike full powered television stations, low power stations and translators were not given a second digital channel so that they could broadcast both analog and digital content. Also unlike full power television stations, translators are not required to cease broadcasting in analog when full power stations shut down their analog services.

What this means in your area is that you will have a mixture of digital only services from KYOU (Channel 15) and KTVO (Channel 3) and analog only services from the translators that carry our service as well as other translators that carry NBC (WHO) and CBS (KCCI). In order to watch all stations, you'll need to use the converter box to watch the digital services and use your television's analog tuner to watch the translators. Hopefully you have purchased a converter box that passes the analog services through when it is turned off. It should say on the box or in the instructions that came with the converter whether or not it does this.

I cannot speak for the other stations that are using translators in that area but IPTV owns the translator that we operate and we will be converting it to digital operation very soon after the analog shut off so that your converter box will receive our service as well.

Bill

Anonymous said...

One problem people aren't always aware of (and could be the cause of a lot of the signal problems) is that the broadcast stations are currently not broadcasting their digital channels at the full power they will be after the digital transition. This is because they are currently having power two signals (analog and digital) and electricity is expensive. Also please note that most of the channels will be moving to the VHF spectrum after the change, currently they might be broadcasting on the UHF spectrum and this might be causing some problems.

Bill Hayes said...

Probably one of the largest misunderstanding that I have had to deal with is related to reception but I am not sure that the stations being at lower power with their digital service is as big a factor as the difference between receiving VHF (2-13) and UHF (14-69) channels.

Whether analog or digital, VHF and UHF channels essentially travel the same paths in the same way. The things that impair them are essentially the same but the manifestation of the impairments is different. Whereas an impaired analog signal may have ghosts or noise in the video, a digital signal will show no sign of impairment, it will just fail. That is a function of the decoder within the digital receiver having insufficient data available off the signal to be able to recreate the image and sound.

For many folks watching with indoor antennas, VHF signals generally work better than UHF signals. This is a function of the physics related to the channels rather than the information on the channels. Since the vast majority of digital services are currently in the UHF band, it is not uncommon to hear someone with an indoor antenna note that they receive the analog service from the VHF channel fine but they get unreliable or no service from the associated digital service. As an example, IPTV's Des Moines station's analog service is on channel 11 while the companion digital service is on channel 50. These two channels propagate (travel) very differently and in the indoor reception environment would behave very differently. The losses associated with outdoor ground clutter (trees, buildings, etc.) and indoor ground clutter (people, furniture, etc.) the degradation of the UHF signal (analog or digital) will be much greater than the degradation to the VHF signal. So while it is true that a number of television stations are running their temporary UHF digital services at lower power, I suspect the difference between VHF and UHF reception is more the issue.

Many of the high band VHF stations (7-13) will actually migrate their digital services to their high band VHF channels once analog shuts down. However, very few low band VHF station (2-6) will be doing this because of the high amount of electrical interference that is inherent in the low VHF channels. The electrical interference shows up as noise in analog video but may cause failure of the digital reception. The decision on the final DTV channels are made on a station by station basis so it may be wise to contact the local stations to find out where they will ultimately end up.

Bill

Anonymous said...

I live in Urbandale and at times can get the 3 channel 11 stations, other times nothing. Living at the bottom of a hill doesn't help. I have an older tv and use a converter. Would buying a digital tv help or am I out of luck? The mobile home park in which I live doesn't allow rooftop antennaes and I don't want to invest in one anyway. Will things improve in June? Also, would a directional antenna be any help in my situation? Rabbit ears only work once in a while.

Bill Hayes said...

Greetings Urbandale,

Indoor reception is the worse choice because it places the antenna in the most difficult environment. A directional antenna may help improve the reliability but there are no guarantees because there are so many variables. Whether it will get better after the end of analog is also hard to predict. Many of the stations are returning to their analog VHF channels which do better getting inside compared to UHF stations but not all of the DTV stations are going to be VHF.

By the way, you may prefer to not install an outdoor antenna but your mobile home park cannot deny your right to put one up. Here is a link to the federal rules that guarantee your rights to install an antenna to receive free over the air television. http://www.fcc.gov/mb/facts/otard.html

Bill

coleo133 said...

Ever since the switch over to digital on Saturday, we are unable to get WOI-TV 5 reception in our TV. We have an outdoor antenna which is about 30 feet in the air. We did get the two channels affiliated with WOI-TV 5 before Saturday, June 12th, but have not been able to get them since. Our TV is a new flat screen, so there is no converter box needed. We live about two hours north of Des Moines, and are able to get all of the other channels just fine. Do you have any suggestions on what we should try?

Bill Hayes said...

Hi coleo133,

I am not completely familiar with WOI's final DTV transmission facilities so you may want to check with them to verify the accuracy of my reply. Since you are still receiving all of the Des Moines stations' digital signals you are obviously aware that as of June 12th, WOI, KCCI and KDIN all changed channels and we returned to our old analog VHF channels (5,8 and 11 respectively). WHO-TV did this change in February. We are all now using the transmitting antennas that we used to use for analog service.

Since all of these transmitting antennas are located very close to each other, your location is not significantly further away from WOI's transmitting site than it is from any of the others. That leaves essentially two other factors.

One is the amount of power that comes out of the transmitting antenna. I am not absolutely sure what power WOI is broadcasting at but based on the information I found at the FCC website, I don't believe the issue is transmission power as the computer models don't indicate insufficient power.

The last variable is antenna height, WOI's transmitting antenna height not your receive antenna. I believe that is probably what you are dealing with. I am not sure of the exact distance that your home is from the transmitting site since "2 hours north of Des Moines" on I-35 is about a 140 miles at 70mph or 110 miles at 55mph or 70 miles at 35mph. I am going to hazard a guess that you are nearly 60 miles away.

WOI's transmitting antenna is mounted on a tower approximately 1,824 feet above the ground. The other stations I mentioned have their transmitting antennas mounted approximately 1,950 feet about the ground so all of those station are about 125 feet higher up than WOI. As the distance of the receive antenna from the transmitting antenna increases, you reach a point where the curve of the earth (the horizon) starts to become the limiting factor on how far a signal can travel. Typically in flat terrain this is pretty predictable and it is based on the height of the transmit antenna and the height of the receive antenna. If either one of these heights is increased the distance to the horizon is increased. If either one is decreased the distance to the horizon is decreased. Since the only signal you are not getting is WOI's, I would speculate that you are near the horizon for receiving all of the rest of the stations and are over the horizon for WOI.

Now being over the horizon doesn't necessarily mean that you get no signal but it may mean that you are not getting enough signal for the DTV decoder in your receiver to decode a picture.

One thing to try would be to install a preamplifier at the antenna to overcome the cable and splitter losses from the antenna to the television. You may be getting enough signal from WOI at the antenna to work but the cable loss may be an issue. Since I do not know what your in house wiring is, this is a guess. Typically cable loss is pretty low for lower frequency VHF channels like 5 but if you are at the fringe and if you have any spitters in the system, this may be the issue and the preamp would overcome those losses.

The other thing that could be done would be to increase the height of the receive antenna thereby increasing the distance to the horizon. If you stand on the roof a two story house you can see further than standing on the roof of a one story house. Raising the receive antenna is a bit more involved since it would mean mounting a taller antenna mast and making sure it is secured for weather and wind.

Let me know it this helps or if there is some other information that would help with the diagnosis.

Bill

Mike said...

I also experienced a loss of channels 5, 11, and 8 with the transition this past Saturday. I received 5-1, 5-2, 8-1, 8-2, 11-1, 11-2, 11-3 until this last weekend. I live in Des Moines. I now receive 13-1, 13-2, 17-1, 17-2, 19-1, and 23-1.

Repeated attempts to reprogram my TV (an LG flat panel less than 1 year old) yield only the same channels. I noticed when running the TV through autoprogram the tuner pauses at 5 and 8, but does not register a channel. I am using a simple Phillips powered set of rabbit ears indoors.

I am having trouble understanding how my equipment found and received these channels until a few days ago, but is now unable. I also am confused by the fact that I do receive some channels just fine.

Bill Hayes said...

Hi Mike,

Until last Friday, WOI (channel 5), KCCI (channel 8) and KDIN (channel 11) were broadcasting their digital services on UHF channels 59, 31 and 50 respectively. On June 12th, all three stations shut down those digital channels and moved their digital services back to their VHF channels. The channel numbers that your television set reports to you are called virtual channel numbers and are assigned based on the stations' original analog broadcast channel. Depending on the choice the station made at the end of the analog, the virtual channel and the actual broadcast channel may or may not be the same.

In the case of Iowa Public Television's KDIN, our digital service was on UHF channel 50 and we opted to return channel 50 and move our digital service to our original analog broadcast channel 11. Therefore our actual broadcast channel will be the same as our virtual channel. KDSM (channel 17) or the other hand decided to stay on their digital channel 16 and return channel 17 to the FCC so even though your receiver tells you that they are on 17, the actual channel the receiver is tuned to is UHF channel 16.

To restore all of your services, I suggest that you tune to channel 13 since they, like 5, 8 and 11 are using VHF frequencies (2-13). On your television you should have an option to look at the signal strength, turn that on. While tuned to channel 13, adjust the indoor antenna to get the best reading you can on the signal meter. This will orient the antenna for the best VHF reception possible. The do a rescan and see if you get the rest of the channels back.

The fact that the tuner delays when scanning indicates that it know there is a signal on those channels but the signal recepetion is impaired enough that the receiver cannot decode the channel. Indoor reception is the most difficult to deal with.

Let me know if that works for you.

Bill

Mike said...

Thanks for the advice Bill. Unfortunately, it did not improve my situation.

Are channels 5, 8, and 11 now broadcasting at a lower power than they were when they were on UHF channels 59, 31, and 50? They came in great with my current equipment when being broadcast on UHF. I never experienced a problem with channel 13. Channel 5 has never really come in here (I'm sure that's a reception/signal strenth/antenna issue).

In fact, channels 8 and 11 have always given me the best reception of any local channels. I'm beginning to wonder if the problem is my TV tuner itself. Signal strength is just not adding up as the culprit to me.

I guess the next step is to bring another TV to my house to see if it experiences the same problem.

Thanks again for your response Bill.

Bill Hayes said...

Hi Mike,

Power probably isn't the issue since you are getting 13. KDIN and WHO share the transmitting antenna so pretty much anywhere you get 13, you should get us.

I have read a couple of pieces that talk about problems that some viewers report about rescanning televisions and converter boxes. On rescans, it appears that some televisions and converter boxes have trouble finding stations that have changed channels. For instance, when you did your initial channel scan, your receiver found KDIN's digital service on UHF channel 50 and stored it so that the receiver knew that when the channel selector called for channel 11, the tuner knew to tuned to channel 50. When KDIN shut down 50 and moved digital service to channel 11, your DTV receiver didn't know that happened so you needed to do a rescan. Now when the tuner scanned and found KDIN's digital service on channel 11 rather than 50, it may not be willing to accept that change.

There are a couple of procedures I have read about with reports of success. One suggests that the viewer go into the setup on their television or converter box and do a factory reset. This restores the television back to the point when you first too it out of the box. It erases all of the channels stored in memory. The tuner then does a complete channel scan and since it doesn't have any of the old channels stored in memory, it doesn't know that any of the stations were on different channels so it adds them as new stations. If your set allows you to do that, I would suggest that as the first step.

Another suggestion is to go into the channel list and manually delete the channels that you used to get and then do a rescan. Theoretically this does the same thing as the above procedure but it takes a few more steps and may not be as easy as a factory reset.

I'd suggest trying one of these ideas to see if that clears up the issue.

Bill

Anonymous said...

Hi Bill,

I live in Boone and I am able to get several channels using my "bunny ears". However, I have never been able to get WOI-TV Channel 5. I have spoken with 6 other residents of Boone and none of them are able to get Channel 5. What should I do?

Thank you! :-)

Bill Hayes said...

The issue you and your neighbors are having with WOI is a combination of at least three factors. Two of the factors are beyond your control which are the height of the transmitting antenna used by WOI and the radiated power from the WOI transmitting antenna. The third factor is receive antenna and that is one area where you have a lot of control. Let me talk about radiated power and antenna height first. Each television station is authorized by the Federal Communications Commission to transmit at a certain power level. That power level is determined by the channel (frequency) that the station operates on and the elevation of the station's transmitting antenna above ground and the local terrain to supply acceptable signal level within a predefined coverage area. The coverage areas that digital television stations use were defined by the FCC in order to replicate as closely as possible, the coverage areas of the original analog stations. Based on the engineering math (not on any measured performance) WOI was assigned a radiated power of 11,500 watts. The other central Iowa VHF stations were assigned the following radiated powers: KDIN - 22,500 watts; WHO - 36,500 watts and KCCI - 28,300 watts.
The first thing you'll notice is that the last three stations all have more power than WOI. The reason for that is that WOI which is a low band VHF station (channels 2 - 6) while the other three stations are high band VHF (channels 7 - 13) facilities. Because of the physics involved in sending radio frequencies through the atmosphere, it takes more power to send a high band VHF signal the same distance as a low band VHF signal. If you were to look at the coverage maps for each of these stations, you would see very little difference between them. The little bit of difference you would see is mostly a factor of the transmitting antenna height. Both KDIN and WHO actually share the same transmitting antenna which is mounted on a tower 592 meters (1,942 feet) above the ground. KCCI's transmitting antenna is also mounted at 592 meters (1,942 feet) above the ground. WOI's antenna is mounted at 556 meters (1,824 feet) above the ground which is slightly more than 100 feet lower than the other stations' antennas. What this difference in height does is reduce the distance from the transmitting antenna to the horizon which means that the WOI signal will not travel as far out as the other stations and the further the receiving antenna is from the transmitting antenna, the more pronounced the difficulty will become. This would account for some of the problem you describe.

Bill Hayes said...

In my opinion, the lion's share of the problem is probably using an indoor antenna. Above I talked about the FCC assigning power levels based on a calculated coverage area. One of the variables used in calculating the coverage area is the receive antenna characteristics. Since there are numerous antenna designs that have different electrical performance characteristics, the assumption was a very basic antenna. However a critical assumption made in the calculation was that the antenna would be mounted outdoors and approximately 30 feet above the ground. This assumption was selected because it was the assumption used in the 1950's when the original analog coverage area calculations were made. The validity of this assumption has been questioned since it was first announced. The closer the antenna is to the ground the less the signal reaching it will be, especially at greater distances from the antenna. Placing a receive antenna indoors, further reduces the amount of transmitted signal reaching the receive antenna. Additionally the indoor environment adds significant reflections (multipath) to the transmitted signal which further degrades the ability to receive the service.
So in conclusion, the combination of power, transmit antenna height and receive antenna location are probably the reason you and your neighbors have difficulty receiving WOI. If you want to test the theory, I would suggest placing the receive antenna outside (temporarily) on the south side of the home and hook it up to the television set and see if the service from WOI is available. You could also check the signal strength of any or all of the signals and note the differences between the received level indoors and outdoors. I hope this helps solve the mystery for you. Bill