HDTV -- UHF Super Antenna

Discussion in 'Off Topic' started by sparky, Dec 6, 2008.

  1. sparky

    sparky Active Member

    =^(

    Once upon a time there was a thread here titled, "Get Yer Gubment Cheese", or something like that. It seems to have been deleted because of the political slant, even tho it was full of good information. I'm against censorship for this very reason. People should be temporarily banned for a few days, or there should be a Political forum added if that many people want it (I prefer the former and let those folks go to another forum, where I won't feel obligated to correct them all the time)... but threads should NOT be deleted. I just don't get the mods sometimes.

    However, I would like to figure out who it was that said they had built a large UHF antenna (yagi?) and got a bunch of Over The Air HD channels. As soon as the OTA HD transition is completed nearly two months from now... people are telling me that it won't be much longer until analog cable is thrown down the ****er. If that's the case... I doubt I'm going to be sticking with cable at all because the encrypted HD channels [prolly] won't work with my MythTV box anymore.

    In this scenario, I'd be happier with 6~10 channels of HD thru MythTV than any free box from the cable company. If I can get more channels, even tho they'll mostly be local channels from all over... I'm ready to learn how to build this super antenna. I think it was machiasmort that was mentioning this, but I'm not 100% sure since I can't lookup the thread!!!

    Any suggested reading or worthy comments??
     

  2. arceeguy

    arceeguy Active Member

    You can get a nice commercially built UHF antenna from Radio Shaft. I bought one, along with an amplifier and I can pick up the two major markets I am in between. (NY and Philly)

    Spent more on the antenna system than I did the stupid converter box. Thanks to the gubmint cheese program, the box was only 9.95 + tax.

    Also wanted to add that UHF transmissions are "line of sight", so at a certain distance it won't matter how good your antenna is.
     
    Last edited: Dec 6, 2008
  3. beachcruiser

    beachcruiser Member

    Not to get off the subject but does anyone know what the goverment is going to use the old airspace for, when we all get converted over? Sometimes I feel the goverment is like the knight piece in a chess game, always three moves ahead in any direction.
     
  4. sparky

    sparky Active Member

    The government's gonna use the old airspace (called white space) for white space devices. The whole idea is that these WSDs have a sensor that detects other wireless frequencies and works around them. Everything from HD signals to wireless microphones spit out black text on a white page; these WSDs detect where the black text is and use the free, white space.

    The whole deal is that FCC auctioned off the white space a number of times (what I'd really like to understand is why it took more than one auction to do this). The final auction results were Verizon on top, AT&T next, and 99 other companies winning this free spectrum in separate markets. As I understand it, there will be one provider in each market... and the providers will not have control over the WSDs it allows, like current cellular providers have (AKA: "open access").

    We will soon enough have wireless broadband, but things are still hazy at this time as to how well this white space broadband will really work. How much we will pay, how easy it will be to move into a different market, how well the sensors will detect existing spectrum from sooo many wireless devices. Most elderly people that have been in the wireless industry for a while don't think it's gonna work too well, but the FCC has already done and will continue to do much testing. We'll soon see as soon as the analog broadcast frequencies turn white.
     
    Last edited: Dec 6, 2008
  5. sparky

    sparky Active Member

    Care to elaborate on this antenna system?

    Luckily, I live in flat land. No mountains for quite a ways away. Not even too many hills around here. It's just lame that I won't be able to pick up Comedy Central, SpikeTV, FX, etc... At least, that's how I'm understanding it. Local channels only, but I'll live.
     
  6. I went here about a month ago:
    https://www.dtv2009.gov/
    And applied for two coupons. I haven't received it yet.
    I have cable and my TV's are digital but I thought it would be nice getting something for free.
    But I'm a bit urked for I have a really nice pocket color TV that would be absolutely useless when this all happens.
     
  7. machiasmort

    machiasmort Active Member

    Sparky,

    The cubical Quad was the antenna design that I built. Plans for it can be found on the internet. I built my VHF for about 25 bucks and you could build a UHF cheaper because it's way smaller!

    The problems: Although I'm a HAM, building was a little complicated because I built mine to transmit off of as well (crankin)! I got awsome TV reception 60 miles from the nearest city (like having cable). My friends would come out and flip at the channels I'd get. VHF is rather large and the antenna is super directional. You might need a rotor to turn it or miss the stations your not pointed at. http://www.softcom.net/users/kd6dks/quad.html

    The only thing keeping me from building another is that I don't know what frequencies the FCC has allocated for DTV yet. Even worse they seem to say or hint in a few years that they may change the freqs. If you build a VHF ANT and the go UHF your dipped!

    If you wanted to mess arround, I'd build a UHF(smaller) one first! If you run into probs just pm me. It's a very rewarding project!
     
  8. sjackson

    sjackson Member

    I built a UHF antenna like the one at this forum:

    http://www.lumenlab.com/forums/index.php?showforum=72
    (you have to register an account to read anything)

    It's the long pinned 63 page thread. I had some 10 gauge copper and all the necessary components. Total cost? $0 (but probably $5 worth of stuff)

    It receives every station in my market, except for the one that is broadcasting VHF.
     
  9. srdavo

    srdavo Active Member

    is this the link you wanted, sparky??

    http://uhfhdtvantenna.blogspot.com/
     
  10. Mr.G

    Mr.G New Member

    I too, would be interested in a great home-built antenna.
     
  11. machiasmort

    machiasmort Active Member

    sjackson,

    Didn't go thru all the nonsense of signing in. Could you just post a pic please?

    SrDavo,

    I must say I'm pretty impressed with that design. For outside and further than 10-15 miles away tho, you won't outperform a cubical quad with that thing! That antenna is of simple design for the home builder! I like it for urban use a lot!

    The trick with antennas is to know where the signal your recieving is comming from. In the S.tier (60miles from Buffalo), I got on my roof with a good compass after consulting a nice map, and had luck the first time! Every degree counts!

    If you get a chance build a UHF cubical quad and get it in the air and do as I described, only point it at the next furthest city away from you (not your own)! Bet you'll have a riot! Make it a seven or eight element, the more elements, the gain (how antennas are measured). Quads have serious gain!
     
    Last edited: Dec 9, 2008
  12. machiasmort

    machiasmort Active Member

    SrDavo,

    As for the transformer that is spoken of in that article. They are commonly known as balauns (available at radioshack). Don't know what you'll pay??? But, you'll want the signal in the wire to be 75 ohms (I believe) to have optimal reception! You might have to measure with an ohm meter what that antenna puts out to begin with!
     
  13. bamabikeguy

    bamabikeguy Active Member

    I'm about to enter this HDTV nightmare, my big old cabinet Zenith has rabbit ears (with a Radio Shack amplifier), and I'm 40-50 miles from the Huntsville and Birmingham stations.

    I tried out the converter box bought when the coupons first came out, that Magnavox with little bitty buttons on the remote (NOT impressed).

    I've done the compass thing, bought the most expensive, longest distance type antenna from Lowes ($79) (with NO instructions in the box).

    So, my question is this- I got a used mast from a neighbor, and am about to do some Stihl sculpturing on an ugly chestnut tree, (my yard has 50 trees, so attaching it to the house is kind of out of the question).

    That old mast had a rusty box on it (about the size of a kitchen matchbox), with a co-axial outlet, so rusty I can't read it, I am going to take it apart an look later....but was wondering, could this be a booster box, AND more importantly, if I have a booster/amplifier on the mast AND the second amplifier on top of the set, won't that be a good thing???

    This HDTV adventure might rival the episode I had shooting down the telephone wire....

    http://www.motoredbikes.com/showpost.php?p=50256&postcount=2

    So I'll be taking pictures during the whole ordeal, so my heirs will know exactly who to sue.
     
  14. bamabikeguy

    bamabikeguy Active Member

    Clarification- got out the magnifying glass, the "mast" part of the puzzle says

    *?*mini uhf/vhf/fm booster 300 o/75 o

    And the Radio Shack devise on top of the t.v. is a RF Modulator

    I guess they still sell those "boosters" for the mast?
     
  15. srdavo

    srdavo Active Member

    hahahaha.... :idea: best to leave the shotgun in the house, this time!!! :evilgrin:
     
  16. bamabikeguy

    bamabikeguy Active Member

    CHESTNUT, God's mosquito of trees, I burnt up a Homelite and a Poulan knocking down eight of the bustards years ago...

    There are 3 obstructing limbs, out of reach of my ladder and chainbar, so explosives ARE in the game plan.

    Remember the guy on the "Red Green Show", who was looking for a woman who enjoyed sitting by a lake, while he tried to explode a Douglas Fir or Ponderosa Pine right over that sucka?

    http://en.wikipedia.org/wiki/Red_Green_Show

     
    Last edited: Dec 10, 2008
  17. bamabikeguy

    bamabikeguy Active Member

    When I get through with this, I'm expecting to pick up signals from TBS-Atlanta, if not Cubs games on WGN!!!

    Here's the platform, the ugliest chestnut tree in America, with a 10 foot new mast and the 20 foot old/recycled mast leaning against it for perspective.

    The plan is to cut that middle limb out of my sight line, but keep enough on to attach guy wires to it. Plus get the lower branches on the other limbs out of my way.

    That tri-limbed fork is approx. 10 foot off the ground. I'm going to bore a hole, the diameter of the mast, maybe a foot deep, to anchor it in hardwood.

    Then either use the new mast OR the old one. The old one will put the antenna (pic 2, somewhat in the direction I'm looking for) 30 foot off the ground.

    Pic 3 is a leftover piece from the mast recycling, and reading the above link, this "screen" would be a good thing to have also, eh??

    The screen wouldn't even have to be attached to the mast, but could be suspended from the limbs using insulated wiring, then connected up to that booster box I was talking about.

    The more I look at it, the more I see renting a cherry picker in my future !!!

    HDTV is going to cost me $2-250, not including labor or emergency room costs!!

    People are going to be P.O.'d in February when the screens go blank !!!
     

    Attached Files:

  18. HoughMade

    HoughMade Guest

    I made 2 of those antennas with the bent copper wire. One with 7 inch "whiskers" for higher UHF and one with 10 inch "whiskers" for lower UHF. They are both pointed in the same direction which gives a gain increase over a single antenna. If they are not pointed in the same direction, then there is actually a loss of gain. I have the antennas combined and fed through a 12db amp to a 6 db per channel distribution amp. I am 40 miles outside of Chicago and I get 33 channels perfectly (one of the broadcasts is closer, but at almost a 90 degree angle to the direction the antennas are pointed, but they come in great.

    The only channel I cannot get is WBBM, channel 2 that currently broadcasts its digital signal in the low VHF band (like idiots). It is going to a high VHF frequency in Feb., so maybe I'll get CBS back then...but I'm not sure i care that much.

    Currently I get:

    5.1- NBC
    5.2- NBC Chicago weather
    5.3- Universal Sports

    7.1- ABC
    7.2- ABC local news and infomercials (yipee)
    7.3- ABC local weather

    9.1- WGN
    9.2- LATV

    11.1- PBS (Chicago)
    11.2- PBS (usually different programming that 11.1)
    11.3- PBS Create
    11.4- PBS spanish

    20.1- PBS (Chicago City Colleges)
    20.2- PBS
    20.3- worldwide news

    26.1- WCIU (The U)
    26.2- Me TV
    26.3- Me Too
    26.4- This (MGM movies and programming)
    26.6- foreign language news (various)

    32.1- Fox

    38.1- ION
    38.2- Qubo
    38.3- ION Life
    38.4- Worship

    44.1- Telemundo

    50.1- My50

    56.1- PBS (Northwest Indiana)
    56.2- PBS Create

    60.1- TeleFutura

    62.1- WJYS (local)
    62.2- Family Net and local (mostly religious)

    66.1- Univision
     
    Last edited by a moderator: Dec 10, 2008
  19. bamabikeguy

    bamabikeguy Active Member

    What a friggin' mess...

    Waiting for the sunrise, to attack the chestnut tree, last evening I trimmed all the "under 20 feet" limbs from two huge oaks in the driveway, which improved my view from the porch.

    (Cutting down all those low hangers really opened up a lot of southern looking sky, spotted a shooting star right about the time my signals all dropped, so I wished a painful recovery to the HDTV executive geniuses).

    I had thought of changing my plan, (from above posting), was going to simply put an antenna about ten feet away from the oak, but now I'm thinking how that will destroy my new view, so it's back to disguising the antenna apparati as part of that ugly chestnut.

    It will be vhf/uhf pointed at 198 degrees (B'ham), with a second uhf pointed at 6 degrees, to pick up Huntsville.

    BUT, here's the nightmare....I bought the two part Radio Shack Booster, scrapped the old RF Modulator. ($59)

    There are NO wiring guidelines for Analog (the 1980's Philco), Magnavox Converter and the 2 part booster combo. Not with the devices, not online.

    Zip, nada, everybody is supposed to run out and buy a new set by Feb, and I'm not putting one of those overheated monstrosities in my house, just to watch 12 fat people get put on an island and CBS call it entertainment. Scr_w those Chinese television products !!

    Anywaaaaaaaay........

    IF you follow the directions on the back of the devices, you get zip, nada, put it this way, the radio is on and an octopus of cables is on the set, (& shotgun is propped in the corner).


    I'm testing it with the rabbit ears, and the hookup sequence would seem to go

    ->antenna->outside Radio Shack booster box->inside plug in Radio Shack box->converter box->television.

    That is how the octopus is hooked up now, and I get NO signal from NO where.

    However......

    I get some B'ham (1 vhf/NO uhf) (NO PBS) and some Huntsville (uhf) by wiring it

    ->antenna->outside RS box->converter box->inside RS plug in ->television.

    But then around an hour ago, all the signals from the 6-8 stations I was getting with that "unconventional wiring" diagram dropped to 1 shaky/freezy/stalling out infomercial.

    Right in the middle of "Monk"


    This is all in the testing with rabbit ears, I haven't even gotten to the doubling of the UHF connections, 30 feet in the air, that are going to have to happen, without the benefit of a cherry picker.

    And don't get me started about trying to find online television listings via AOL and TV Guide, they have made THAT searching a complete fiasco...


    Rabbit ears at least give me my daily Elliot on Scrubs "fix", but HDTV can't pick up the CW channel at all.
     
  20. bamabikeguy

    bamabikeguy Active Member

    (oh, and I forgot, the DVD player is out of the wiring sequencing altogether, I figured it would melt, with my luck).

    Wonder where in the scheme of things, that is supposed to hook in????
     
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