Good FM antenna?

Discussion in 'Archived Threads 2001-2004' started by Oren, Sep 30, 2002.

  1. Oren

    Oren Stunt Coordinator

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    I'm not sure if this belongs here, but can anyone recommend a good FM antenna? Right now I have just a set of rabbit ears connected to the coax input.
     
  2. Chu Gai

    Chu Gai Lead Actor

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    Do you live in an apartment with buildings around or is it more open? Are able to mount an antenna on the roof or are there limitations? Also, assuming you have cable, does your cable company provide an FM feed along with the cable?
     
  3. JayDaniel

    JayDaniel Stunt Coordinator

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    You are going to think this is crazy, but the best one I've found (short of a roof mount model - which I haven't tried) is a simple $2.00 dipole fm antenna available at Rad. Shack, Walmart, BB etc.

    I tried powered and non-powered ones from Radion Shack and Terk, and found the $2.00 dipole to work better than any. It's worth a try for you, as it doesn't cost much, and you may find similar results to mine. If not, hey, you're out $2.00.

    JayDaniel
     
  4. Walter Kittel

    Walter Kittel Producer

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  5. Chu Gai

    Chu Gai Lead Actor

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    The Dynalab might work but if his problems have to do with multipath reflections, then a vertical dipole won't do squat as it has nothing to speak of in terms of multipath rejection. One would have to experiment a bit with such an antenna and that includes a horizontal position. In situations like that you'll do far better with a directional antenna...provided you've got a place to mount it!
     
  6. Oren

    Oren Stunt Coordinator

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    I live in an apartment. The complex is 3 stories and I'm on the second floor. It's not one building, though. It's a collection of closely packed smaller buildings connected by walkways, etc. I do not subscribe to cable TV--I have a satellite dish mounted on my deck/patio.

    What's the best way to mount a dipole antenna? I'd spring for the $2! As a flat T, as high as possible? A 90 deg. bent T, like in the corner?
     
  7. Chu Gai

    Chu Gai Lead Actor

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    Well this link goes into how to make one. If it doesn't help you out you're out a couple of bucks. BTW, what's the nature of the specific problem that you're having?
     
  8. Jason Wilcox

    Jason Wilcox Supporting Actor

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    i've tried dipole antennas with 300ohm lead and 18g speaker wire....i really couldn't tell a difference...should i?
     
  9. Chu Gai

    Chu Gai Lead Actor

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    nope. it's a question of length. the link gets into it a bit.
     
  10. Oren

    Oren Stunt Coordinator

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    Wow, there's a web page for everything!

    Right now, with the rabbit ears attached, the antenna has to be positioned just right to receive (and it varies from station to station) and with some stations I need to touch the antenna.

    Why does reception change (improve) when a person is touching the antenna?
     
  11. Clay Autery

    Clay Autery Stunt Coordinator

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    Oren,
    I suspect that touching the antenna does one of two things...
    a) You increase the loop size and hence change the tuning of the dipole to a different fequency, or
    b) You change it from a zero gain dipole to a "different type" of antenna with some directional properties (gain) and maybe some front/back rejection qualities...
    I'm not sure which... but I would suspect that your body acts like a resistor of sorts taking that end of the dipole to ground, thus making the antenna a sort of directional "long wire" antenna...
    Just guessing...
    I've tried all kinds of FM and UHF antennae in the last few years, and basically there is no substitute for size or height above the surrounding terrain...
    The BEST FM antenna "I" know of is the APS-13 from Antenna Performance, but it is VERY large... But it provides great directional and front/back properties.... With a rotor and a mast that'll put it up above the roof line, it'll pick em up a LONG way away...
    Even with a half or full-wave dipole properly constructed, you still have need for a means of rotating the antenna for the best performance if the stations you wish to tune in are on more than a single azimuth from your location... as the antenna needs to be oriented perpendicular to the azimuth line between the transmitter antenna and the receiving antenna...
    I've never needed to worry about FM reception AND live in an apartment...
    You will of course be restricted by the line of sight off your balcony and how it relates to the locations of the transmission towers... You might want to consider a stealth installation... paint an antenna lead the same color as the building exterior or trim and run it up the "back" side of the building exterior in hours of darkness.. and plant an antenna on the roof somewhere...
    It's difficult to do, but has been done successfully before... You might also try the "ask permission first" approach, but you will likely be denied.... Folks seem to hate antennae UNLESS THEY need them. [​IMG]
     
  12. Chu Gai

    Chu Gai Lead Actor

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    The thing with antennas that include some sort of amplifier is that they also amplify noise and possibly bleedover from nearby stations. It's a very iffy proposition the success of which depends upon what the nature of the problem is and what one is trying to achieve. If it's simply boosting the signal of a weak station enough then it may be the solution. If I were investigating this then I'd surely look at buying locally with a money-back guarantee.
    There's no question that reception is improved when an antenna is placed outside and further improvement can be had as it's raised higher and rotated in order to maximize the signal from a particular station.
    However in an apartment this may be very problematical as restrictions are the norm. In a building, even if it were the only one standing, reception can be problematical with an antenna inside. Issues of wiring, steel beams, etc. can wreak havoc with signals.
    As Oren and Clay touched upon (no pun intended) the person or persons have a profound effect on the reception whether by touching or standing in a particular place or angle. The reasons for this have to do is that people can have an effect on the signal's absorption as well as affecting induction. In fact there have been studies where the human body is looked upon as a cylinder of salty water for predicting RF absorption. The body is electrically conductive, and therefore also has currents induced in it by the broadcast RF field, just like the antenna does. The fields produced by those induced currents in your body interact with the antenna, which can increase the effective RF collecting power.
    Let us know what you tried and how you made out [​IMG]
     
  13. Oren

    Oren Stunt Coordinator

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    Well, things are going in the right direction. I picked up a T dipole antenna from RS last night and things definitely improved. Properly positioned, the reception is not bad with the antenna inside.

    However, since everyone says that the walls, etc. can block the signal and I can't find a discrete place to mount it inside, my plan now is to run coax from the receiver to my deck (using one of those flat 12" coax cables from RS to get by the door) and mount the antenna as a T outside on the deck. (It will still be blocked somewhat, tho.)

    I trust that connecting the antenna to the receiver over insulated coax won't be a problem (actually, it may help prevent deflections or whatever).
     

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