What's the most optimal place to put your indoor antenna?
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What's the most optimal place to put your indoor antenna?


This is a discussion on What's the most optimal place to put your indoor antenna? 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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    What's the most optimal place to put your indoor antenna?

    I'm thinking that it's the window, but I've seen a few of the "pros" on here poo-poo that idea. I know height is a major plus, but lets discuss in terms of vertical placement. What would be a bad position to place an antenna next to?

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    In the attic.

    Otherwise, in a window facing the transmitter towers. To find out where your towers are, enter your address at http://www.TV Fool.com

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    The best place to place an indoor antenna is where it works the best. I am not being silly. Every structure will behave different. Then throw in different distances and orientation to the tower.

    For the sake of this scenario lets say all stations transmit horizontal (take elliptical out of the equation). Lets also take reflections from other structures out also. So we pretend the waves are horizontally polarized outside your residence.

    First if there are wires or metal studs in the walls that are 1/10 of a wavelength apart, it's like having a solid metal barrier to a radio wave just like if you have foil insulation.

    If the studs or wires are 1/4 wavelength apart they will substantially reduce the signal. This at 1/4 wavelength is:
    Low Band 45 inches
    High Band 15 inches
    UHF Ch 20 5 inches

    So as you can see it wouldn't take much to significantly reduce Low Band. Even wires in the walls of a totally wooden structure play a major role.

    At 15 inches if metal studs are on 18 centers, that is close enough to block most High Band.

    But few places in the home is there metal within 5 inches of the next piece, save metal foil backed insulation.

    ------

    So UHF penetrates the structure in many places. So placement of a UHF can be much less critical.

    VHF may only enter the house through a window that is more than 30 inches wide.

    ---------

    But once inside the house, it will bounce and reflect off other walls and objects. It will also not only reflect but change polarization, depending on the object reflecting it. The result are waves entering through holes, then bouncing off things. When waves that bounced strike waves that didn't or off a different object interference patterns emerge. The makes strong and weak spots all over the place. (If this doesn't make sense it's wave theory).
    This gif legally lifted from Wikipedia per the authors copy left statement, show two sources with the waves interfering. The source are the two red blobs. the other colors moving show places where the waves add and where they subtract from each other.



    The one problem with this image that isn't like the insides of a room, are the strong and weak spots don't move like in the image.

    ===

    So there are a few places that tend to work better. Near a window for VHF. Up higher in the room. But it's not written in stone.

    A lot of people believe that since most stations transmit horizontal then rabbit ears must be placed straight out in a horizontal orientation. This only works if the reflections indoors on VHF are at a minimum. Other wise it's best to place them in a Vee and then if the signal are horizontal or vertical they will be received. In a Vee is the best orientation to find a hot spot. Then one can experiment with lowering them horizontal.

    ========

    So the best place to put an indoor antenna is to get one with about 12 feet of coax and try it all over the place.
    The more I understand, the less I know.

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

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    Quote Originally Posted by Eureka View Post
    In the attic.
    Otherwise, in a window facing the transmitter towers. To find out where your towers are, enter your address at http://www.TV Fool.com
    Eureka, sorry I didn't explain, I posted this thread for discussion purposes. I get fine reception here in LA with a Terk HDTVi.

    Quote Originally Posted by Piggie View Post
    The best place to place an indoor antenna is where it works the best. I am not being silly. Every structure will behave different. Then throw in different distances and orientation to the tower.

    For the sake of this scenario lets say all stations transmit horizontal (take elliptical out of the equation). Lets also take reflections from other structures out also. So we pretend the waves are horizontally polarized outside your residence.

    First if there are wires or metal studs in the walls that are 1/10 of a wavelength apart, it's like having a solid metal barrier to a radio wave just like if you have foil insulation.

    ------

    So UHF penetrates the structure in many places. So placement of a UHF can be much less critical.

    VHF may only enter the house through a window that is more than 30 inches wide.
    So it's really dependent upon how the house is built...but, are you saying a window THE ONLY means of receiving a signal then inside?

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    Depends on what the walls are made of.

    The hot spots definitely exist indoors, at least for my lone TV using indoor loop/dipole antenna. Where I set the antenna has a lot more effect on reception than what direction I aim it, at least for UHF. For VHF, I barely get anything, because I have foil backed insulation in the exterior walls and metallicized low-e glass in the windows.

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    Thanks for your answers!

    I've been helping a few people in my apartment complex with setting up their antennas. I knew that building materials affect reception, and that placing the antenna in a higher location, closer to a window would help, but never knew exactly why.

    One thing to note, everyone on the second story of my complex gets pretty good OTA reception while the first story folks have a bit tougher time. I wonder if it's due to having more building materials above them on the first floor or if the second story has the advantage with being able to place their antennas higher, or a combination of both.

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    Quote Originally Posted by Aaron62 View Post
    So it's really dependent upon how the house is built...but, are you saying a window THE ONLY means of receiving a signal then inside?
    Saying a window for VHF is one of my most likely places, but more so, every house is built different, distance to the tower, number and size of other windows that predicting where a signal is strongest in a house without moving the antenna around you would need a Cray computer.

    Obvious first choices are windows and up higher in the room, but that doesn't guarantee you found the best spot. Buy 12 feet of jumper and move it around if not happy on it's short cord.
    The more I understand, the less I know.

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

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    Quote Originally Posted by Eureka View Post
    Depends on what the walls are made of.

    The hot spots definitely exist indoors, at least for my lone TV using indoor loop/dipole antenna. Where I set the antenna has a lot more effect on reception than what direction I aim it, at least for UHF. For VHF, I barely get anything, because I have foil backed insulation in the exterior walls and metallicized low-e glass in the windows.
    Yes, this is exactly what I meant. I can understand that hot spots in your case would be more important than direction.

    Lets see if I can put this simpler. One the waves enter the room, direction can become confusing or moot. Most of the time the antenna is not directed at the station, because it's picking up waves indoors that are bouncing off everything inside.

    The hot spots. If two bouncing waves arrive at a location in the room, that traveled different distances in the room, they can cancell each other out making a dead spot, this is called arriving out of phase.

    But if two bounced wave travel the same distance to a spot (two waves bouncing off different objects or walls) then they add and are stronger than either of the two waves that bounced, thus a hot spot.

    (now to be technically correct, two waves can arrive at a point even if not the same distance of a bounce if they are equal multiples of a wavelength in their paths. If any of you took Vector Analysis in College, think of the two bouncing waves as two vectors. If the vectors have the same angle, they add, if 180 degrees then total subtraction. Between those angles there are various amounts of addition or subtraction.)
    The more I understand, the less I know.

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

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    Quote Originally Posted by Aaron62 View Post
    Thanks for your answers!

    I've been helping a few people in my apartment complex with setting up their antennas. I knew that building materials affect reception, and that placing the antenna in a higher location, closer to a window would help, but never knew exactly why.

    One thing to note, everyone on the second story of my complex gets pretty good OTA reception while the first story folks have a bit tougher time. I wonder if it's due to having more building materials above them on the first floor or if the second story has the advantage with being able to place their antennas higher, or a combination of both.
    The ones on the second floor have several advantage.

    1) just plain higher and closer to Line of Sight
    2) there isn't a floor above them to block signals, only the roof. First floor has a roof and a floor above it.
    3) may be above the cars in the parking lot reflecting a lot of signals, or shrubs planted outside the windows blocking UHF.
    4) may put them above a ridge on building next door blocking direct LOS to the towers
    5) The roof might not have any metal in it, so signals come in through the ceiling for them, where the angle to the roof on the first floor is too steep for signals to get in the room from the tower.
    6) And it's possible the second story is built different in the walls. (here in Gainesville there are a lot of town houses with cement block on the first floor, but wooden walls on the second.
    The more I understand, the less I know.

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

  10. #10
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    Very informative. One of the problems at my condo is that I have an attached garage on the west side of my unit, which is directly in front of my LOS to the broadcast towers. The garage door has some insulation with some type of reflective metallic material that I'm guessing is used to reflect heat? Anyway, it messes a little bit with my reception. I can get signals better with a set of bunny ears and uhf loop than I do with my Phillips Silver Sensor because I'm guessing the bunny ears are less directional. It helps being closer to the towers too.

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    Certain items near the antenna, especially radio's and such, and even simple inanimate objects can mess up the signal. I remember my granda placed his radio in such a way he could tell if somebody was trying to sneak into the kitchen.

    I myself place my radio in such a way that I can tell if my boss is going to sneak up on me when I'm skiving off instead of working. Hell, I can also mute the radio by putting my hand in a specific location, everyone is convinced that I have psychic powers.

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    Quote Originally Posted by Aries View Post
    Certain items near the antenna, especially radio's and such, and even simple inanimate objects can mess up the signal. I remember my granda placed his radio in such a way he could tell if somebody was trying to sneak into the kitchen.
    I've noticed that too, it's almost like a feedback or something.

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    Quote Originally Posted by O-O View Post
    ... I can get signals better with a set of bunny ears and uhf loop than I do with my Phillips Silver Sensor because I'm guessing the bunny ears are less directional.
    A VHF/UHF rabbit ear/loop antenna is much less directional than a UHF silver sensor.

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    Quote Originally Posted by O-O View Post
    Very informative. One of the problems at my condo is that I have an attached garage on the west side of my unit, which is directly in front of my LOS to the broadcast towers. The garage door has some insulation with some type of reflective metallic material that I'm guessing is used to reflect heat? Anyway, it messes a little bit with my reception. I can get signals better with a set of bunny ears and uhf loop than I do with my Phillips Silver Sensor because I'm guessing the bunny ears are less directional. It helps being closer to the towers too.
    Do you have VHF there? Remember a Silver Sensor is a UHF only antenna.

    It comes from the era where we really did think the USA was only going UHF only for Television.
    The more I understand, the less I know.

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

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    Quote Originally Posted by Piggie View Post
    ...It comes from the era where we really did think the USA was only going UHF only for Television.
    We had VHF DTV here from day 1. Although it's never worked well and I wish it would just. go. away, I knew it wasn't in the plan to get rid of it.

    Funny how that ("UHF") myth took hold.

  16. #16
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    Quote Originally Posted by Eureka View Post
    We had VHF DTV here from day 1. Although it's never worked well and I wish it would just. go. away, I knew it wasn't in the plan to get rid of it.

    Funny how that ("UHF") myth took hold.
    Oh crap, I have to google again, but too lazy.

    Note "we really did think".

    And even though there were VHF licenses handed out just like there were out of core UHF licenses handed out and constructed, there was more than one band plan over time. One of those plans didn't include VHF. Wish they had of stuck with that idea also.

    If so I would not receive my Jax VHFs, but more than likely the NBC that I "should" be watching would be receivable.
    The more I understand, the less I know.

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

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    All I know is, a front's moving through here today with the usual lightning and T-storms. So no reliable reception for me of PBS 9 or CBS 10. At least I have a second PBS & CBS to pick from, on alternate UHF affiliates.

  18. #18
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    Good information here.

    Materials that block RF or reduce its penetration or actually reflect RF.

    Metal siding and roofing
    Masonry, Concrete, Stone, Brick
    Stucco, often use metal chicken wire as substrate
    Terra cotta, roofing tiles

    Then there is the elusive Foil Backed Insulation or Foil Vapor Barrier.

    This is besides the metal pipes and wires in the walls which can and do affect indoor antennas.

    Also large metal objects inside the home, like stainless steel kitchen appliances, range, refridgerators, etc.

    Dont forget mirrors, which are often aluminized or silvered.

    Fish Tanks full of water! RF dont travel through water to well.

    Then on to interference sources, electrical devices, including TVs! Microwaves and Computers are notorious sources of interference.

    My 2 cents.

 

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