can't get CBS in Illinois

can't get CBS in Illinois


This is a discussion on can't get CBS in Illinois within the DTV | HDTV Reception and Antenna Discussion forums, part of the Over-the-Air (Antenna TV) category.

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  1. #1
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    can't get CBS in Illinois

    TV fool = TV Fool

    Antenna = Phillips SDV6122/27 - amplified HDTV/UHF/VHF

    The only over the air channel I care to get is CBS and it I can;t seem to get it to come in. I bought this antenna and still no luck. I am getting the stations on the list that are 28 miles away but can't get CBS which says it is 21 miles away. What gives? Help me out please!

  2. #2
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    Indoor antennas can be funny animals, especially at the distances you are talking about. You have to have them turned just right and since different stations have broadcast towers in different areas, it might not bring in all the stations clearly without turning it every time you change channels. Also the location of the antenna in your home can affect reception. Try moving it to different locations and turning it in all directions at each location.

    Have you considered trying an outdoor antenna?

  3. #3
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    Especially at 28 miles away from broadcast towers. I don't think an indoor is going to work for you. It's odd that CBS is less distance than other channels you are getting. Have you tried moving the antenna to a higher point atleast?

  4. #4
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    Hello odog, and welcome to the forum.

    You have pretty strong signals according to your TVfool. That you are having trouble with CBS (Real Channel 4), indicates the problem. Its VHF Low and subject to not only necessitating long antenna elements, but also interference and noise from a variety of sources.

    The first thing you should try before you ditch your current antenna and get something else is tuning your Rabbit Ears VHF dipoles for channel 4.

    KYES has some good tips on doing so....

    How to get more out of Rabbit Ears

    The short version is extend your Rabbit Ears out about 80" total or 40" per telescoping dipole...place them horizontally and inline with the UHF loop panel...then situate perpendicular to the direction of the transmission towers.

    It should be OK and beneficial to have amplification.

    Here is the manual for the Philips SDV6122/27 (pdf).

    Hope that helps. If not, I can assist in antenna recommendations.

  5. #5
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    Thanks for the help so far guys. With the antenna I listed I have not been able to get the channel to come even close to coming in but with an old pair of rabbit ears I found in the garage (roughly 36in. dipoles each) I was able to get a signal finally last night that was steady but now today it is pixelated and not coming in very well at all. I think I might be able to get these rabbit ears to work with some tweaking? I have them facing mostly west slightly south and actually right outside my bedroom window. I might be able to try to get them higher up as I have a little extra cable. Is there any other little tweaks that might work like adding something to the dipoles?

    If not, it looks like I'm needing a rooftop antenna possibly?

  6. #6
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    Do they have little metal bulky tips on teh ends. If so, your are right in the neighborhood of 1/2 wave at Channel 4 with full extension and should be good to go as far as length of the dipoles go.


    Unfortunately the next step up for you in VHF Low Land is a big yagi.

    Like the Channel Master 3016.

  7. #7
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    VHF, particularly lowband VHF channels 2 thru 6 are very long wavelength radio waves that do not penetrate walls very well at all. Also, indoor electrical appliances give off all sorts of interference in the VHF band, especially lowband VHF.

    If you expect to reliably get channel 4, you will likely need an outdoor antenna, installed far away from all the light switches and appliances inside your house. You should not need an amp. Amps often make VHF reception worse by amplifying the noise level.

    Also, complain to the station. Only fools stayed in the VHF band.
    Last edited by Eureka; 08-09-2009 at 11:45 AM.

  8. #8
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    In case you do get interested in putting up an outdoor antenna, check out a Winegard HD-7080P. There are a couple of Winegard and a Channel Master antennas that might save you a few bucks, but they're not built nearly as well and their gain figures fall way short of this one, particularly at channel 4. Antenna, mast, mount, coax cable and sundries should run maybe $150. It may sound like a lot compared to an indoor antenna, but Winegard Platinums are known for providing decades of reliable service when installed well.

    Is it convenient for you to drive to Moline? If so, you might wish to visit Warren Electronic Distributing, which has a full line of quality antennas and accessories, and is known for being both knowledgeable and helpful. Here's a map. Their prices may not be the cheapest around, but shopping them in person means avoiding substantial shipping costs -- and increasing the chances that you'll get everything you need to do the installation right the first time.

  9. #9
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    Quote Originally Posted by odog View Post
    I think I might be able to get these rabbit ears to work with some tweaking? I have them facing mostly west slightly south and actually right outside my bedroom window. I might be able to try to get them higher up as I have a little extra cable. Is there any other little tweaks that might work like adding something to the dipoles?
    That may be possible, though you may not care to keep the results indoors. Since Ch 4 is your only VHF station of any kind, your needs are simplified somewhat (other than the physical size required by this long wavelength).

    The wavelength of Ch 4 is about 160". So, a half-wavelength dipole will need to be about 5% less than 80" wide, and even less with capacitance hats at the ends. So, your 36" is right in the ballpark. Fortunately, you have a moderate to strong signal, and your stations of interest form a fairly narrow grouping.

    The gain and directivity of your dipole can be improved by adding director and reflector elements (collectively known as parasitic elements), turning your basic dipole into a classic Yagi-Uda antenna. The reflector is on the opposite side from the transmitter, about two tenths of a wavelength behind, and it is a bit longer than the dipole. In contrast, the director(s) are on the side towards the transmitter and are shorter than the dipole.

    Also, you could start with an twinlead FM folded dipole antenna to form the Yagi driven element, or build it from wire or tubing. This requires a balun for attachment with the 75-Ohm coax cable. There are number of places describing the design and contruction of Yagi-Uda antennas on the Internet, such as these:

    A cheap and easy TV antenna

    Dimension_Table


    http://www.k7mem.com/Electronic_Notebook/antennas/yagi_vhf.html


    There are trade-offs to be made, so there are several strategies around for the exact size and arrangement of the parasitic elements. Roughly speaking, doubling the length of the Yagi boom will give almost 3 dB of extra gain. But, for your signal strength, you probably only need 3 or 4 elements (unless you suffer from multipath or other interference problems). Even if you build something else, you should be able to use your rabbit ears for experimentation. If you can find more rabbit ears or other bits of metal, they can serve as the reflector and director elements.

    The few commercially available single-channel VHF Yagis tend to be a bit pricey. So, a combo VHF/UHF antenna will be more cost effective.

    If not, it looks like I'm needing a rooftop antenna possibly?
    Possibly. The single channel Yagi-Uda is a two dimensional array of wires, so it might be mounted along the surface a ceiling. This would require combining with a UHF antenna, possibly the one you already have, using a UVSJ (UHF/VHF Separator/Joiner) device, such as this:


    Pico Macom UVSJ UHF VHF Band Separator/Combiner for Antenna (UVSJ) | UVSJ [Pico Macom]


    The VHF/UHF combo antennas have UHF corner reflectors that stick out above and below the main boom, so they would have to go outside or in the attic. You have enough signal that you probably can get away with the attic mount, if that is feasible at your place.

    As always, EV's suggestion of the CM 3016 (a VHF/UHF combo) for your TVFool data looks good. Here is a comparison chart of CM antennas:


    Channel Master Antenna Reference Chart | Solid Signal


    While looking for a VHF/UHF combo antenna, be sure to get one with adequate gain in the VHF-lo band. There are few of those stations remaining, so many antennas on the market are VHF-lo/UHF combos.

    If you install outdoors, be sure to follow your local codes for mounting and grounding.

    Good luck!

  10. #10
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    You guys have been a ton of help. We just changed to dish and I was unaware that we would only get SD locals and lose our HS locals we got from cable. It looks like from what I'm hearing and experiencing that I'm going to have to go the outdoor antenna route.

  11. #11
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    Football season is upon us. CBS is primetime for Da Bears!

  12. #12
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    Quote Originally Posted by Eureka View Post
    VHF, particularly lowband VHF channels 2 thru 6 are very long wavelength radio waves that do not penetrate walls very well at all.
    Depends on the wall. Just like the difference in high band and UHF.

    UHF has the ability to not penetrate walls but sneak in through openings.

    So if there is any metal in the walls, UHF will get indoors the best.

    But it one lives in a wood framed house with a wood and tile roof low band will go indoor fine.

    The kicker is so much foil backed insulation and metal studs in new homes will block most VHF even if it looks like all wood. Some newer roof tiles have enough metal in them to block a lot of signal too.
    The more I understand, the less I know.

    PORK... The Other White Meat....

  13. #13
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    Quote Originally Posted by flcs3 View Post
    Note this table is for FM radio and would need to be adjusted to VHF.....
    The more I understand, the less I know.

    PORK... The Other White Meat....

  14. #14
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    Quote Originally Posted by Don_M View Post
    In case you do get interested in putting up an outdoor antenna, check out a Winegard HD-7080P.
    If money and putting up an outdoor antenna is not a problem, I agree with Don, this antenna has a lot of bang for the price and size, in particular on Ch4 where you need it.

    If you are pixelating inside in the day, I doubt a lot more of what you could do inside would help. Ch 4 was a huge mistake for CBS to pick, because all the channel 2-6 are not suitable for digital due to noise mainly. Where they put some annoying lines in analog, in digital you get a blank screen with noise.

    I would not put up an amp right away if you only have one tv and less than 30 ft of cable from the antenna outside to the TV set.

    The fact the old rabbit ears worked better are two fold. One is they are longer and closer to being tuned to ch4, but just as much if not more, they are not amplified.

    This is why I suggest you not use an amp or experiment without one first, then if you want to try one do so. The amp on your indoor antenna is probably amplifying the noise as much as the TV signal.

    Still be fore warned. Ch4 is a hard signal to pick up. You stand a good chance with them running 24 KW at 22 miles from you with an outside antenna. But there may and probably will be times it just won't come in. More likely during the day when more electrical stuff is running and there is a chance of E-skip.
    The more I understand, the less I know.

    PORK... The Other White Meat....

  15. #15
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    Quote Originally Posted by Piggie View Post
    Depends on the wall. Just like the difference in high band and UHF.
    True. I should've said VHF won't readily penetrate walls roofs or windows that contain certain building materials. The long wavelength VHF signals get mangled, but the shorter wavelength UHF signals can make it through relatively intact.

  16. #16
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    Quote Originally Posted by Piggie View Post
    Note this table is for FM radio and would need to be adjusted to VHF.....
    Ooops. Thanks for that catch. I had a misfiled bookmark and only checked it for staleness.

  17. #17
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    Quote Originally Posted by Eureka View Post
    True. I should've said VHF won't readily penetrate walls roofs or windows that contain certain building materials. The long wavelength VHF signals get mangled, but the shorter wavelength UHF signals can make it through relatively intact.
    If you do any ready and you may have on reflector specifications for screen reflectors be in a yagi, bowtie or even building a dish for VHF, UHF or microwave. Good example of a dish on UHF is the old CM4251.

    Remember any mesh screen where the holes (spaces between the metal) are less than 0.1 wavelengths the radio wave sees this as a solid piece of metal. This can be seen in many ways. Simplest might be just the effect of the metal being that close to the wave. It can also be shown considering the radio signal as particles and not waves. This gets bizarre to think about since it doesn't make any sense. It would seem if light photons were very small they would go through anything wider than them. This can be shown with the classic 2 slit experiment where light appears behind the slits in a place where there isn't a slit (same theory as slot antennas). Well they appear in a place between the slits because it is a wave and a particle at the same time. If you think about this, it's really even more bizarre. The particles in the 2 slit experiment not only go through the slit as expected but as above also appear between the slits. This means the particle is in two places at the same time.
    Double-slit experiment - Wikipedia, the free encyclopedia
    Classic Two-Slit Experiment

    So even though can shoot a bullet between the metal in a mess reflector the waves won't penetrate it.

    =========

    So what is 1/10 of a wavelength at common TV frequencies? These are approx for example

    Lowband 18 inches
    Highband 6 inches
    UHF 2 inches.

    So to block a UHF TV station from entering the house one would have to put a wire or some piece of metal every 2 inches both horizontally and vertically, so that no area of the wall had a gap of more than 2 inches if wishing to reject both horizontal and vertical waves. As you can see houses aren't built that way unless they have solid metal walls or roofs. UHF gets through windows and walls. Even metal studs are not close enough together to stop UHF.

    On highband metal studs in the walls spaced on 18 inches would not be a perfect reflector, they are spaces at 3/10 of a wave length, giving a great deal of blockage. As you can then see low band really has a hard time finding a hole large enough to get in, unless the house is soley wooden and little wires in the walls.

    There is the large and small of it.
    The more I understand, the less I know.

    PORK... The Other White Meat....

  18. #18
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    Quote Originally Posted by flcs3 View Post
    Ooops. Thanks for that catch. I had a misfiled bookmark and only checked it for staleness.
    That chart does work extremely well for high band TV antennas, since the entire second harmonic of the FM band is TV high band (yes it was done on purpose). So one only has to divide the high band frequency by 2, then look up that FM frequency, then divide all the dimensions by 2 giving the size and spacing for high band.

    To use the table on some of the higher low band channels you need better ratio math skills than just factors of 2.
    The more I understand, the less I know.

    PORK... The Other White Meat....

 

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