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Installing FM Antenna

Ok pardon the seemingly simple question but I need a little help here.

I got a simple FM antenna (cheap wire that splits into a Y) and has a coax-like connection with my ATI TV Tuner card, so I thought, hey I can connect this to my home stereo and finally get FM radio.

The problem is it sounds GREAT when I am holding it.. and crappy once I mount in on the wall permanently.  My wall now has a few dozen holes as I have tried to move it around the room and it still sounds bad.  Like the FM stereo light is flickering as it tries to tune into the station :(

I thought maybe the cable needed to be taunt, but that didn't help.  One thing, if they touch eachother - nadda - just dead air.

Can anyone recommend a solution to help get crystal clear sound from these babies without me holding them?
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cboyda
Asked:
cboyda
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1 Solution
 
simpswrCommented:
How long is the wire? . . if it works when you hold it, it probably needs to be longer . . Do you have it split into a "T"? . . each leg of the "T" should be around 6 feet long . .
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OkigireCommented:
This may be the wrong place to ask this question.  I remember being on a "radio" forum years ago where people could talk in a language some people wouldn't understand.  ;)  If I'm correct, it has something to do with a grounding effect of you physically holding the wire.  Perhaps there's a radio expert who will find your post.

Instead of drilling holes, why not use pieces of tape to temporariliy hold it in place to test?  This way you can drill a hold only when you find the perfect position.

If those things don't work to your satisfaction, I'd look at getting another antenna, signal booster, or what is almost guaranteed to work: an external antenna, then running some cable to your radio.
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octothorpeCommented:
do the "few dozen holes" include mounting the antenna on adjacent walls?  For best reception, the antanna should be mounted so it exposes the maximum length of wire to the signal.  Moving it around the corner (turning it 90 degrees) might help.

Ideally it should be mounted with the wires horizontal, but it's also possible to hang the antenna vertically.  I can't explain why that sometimes works better - the engineers talk about horizontal and vertical signal polarization and lots of other techno-speak, but I know that in my basement, I mounted one of these by hanging it from a push-pin in the ceiling joist and it worked better than when I tried to mount it horizontally...

    --- octo
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scrathcyboyCommented:
"crystal clear sound from these babies without me holding them"
You have to hold all babies until they are 12 years old, didnt you know?

Seriously though, I had the same problem.  The antennae dont get good reception unless you are right near your FM station.  If you had satellite, then you can get great FM fed through the cable, only trouble is, there a 100001 rock stations and no good classical music on satellite, because they too stupid to know.

So you will have to put up with the reception you get, unless you want to try to hook up roof antenna to your video card, then you risk serious shocks to your computer when storms, wind, lightning come by.  No easy solution except satellite, then you suffer one good classical station and hundreds of useless stations.
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PCBONEZCommented:
Cripes man.. USE PUSH PINS!!!!
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PCBONEZCommented:
http://www.kgnu.org/howtohear/antenna.html

Sometimes I tape one end to something metal, an aluminum window frame, light fixture, pipe.
(Tape down, not connect.)
Sometimes a metal screen on the other side of the glass through a window with part of the antenna taped to the window changes things.
Never found anything that -always- works. Just gotta play with it..
.
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scrathcyboyCommented:
PCBONEZ -- he is talking about the antennae effect from the human body, it is substantial, and push pins dont substitute for a good body as an add-on antenna to the existing one.  I had exactly the same issue with the same type of antenna to the TV card, when you hold it, it amplifies the reception about 3x.
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cboydaAuthor Commented:
FYI
The cable is only about 2 feet long, then the Y's are each about 2 feet.  Ya, pretty short but I was excited when I got sound out of it at first.

I will try the horizontal vs vertical.

Unfortunately there is no metal in the area to connect it to.
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PCBONEZCommented:
scrathcyboy
I know exactly what he was talking about.
You dunno what I was talking about.
Push pins make smaller holes in walls.

The human body is a big bag of salt water and makes for a pretty good conductor.
Antennas are made out of conductors.

Are the Y's (top of the T) a single wire or two wires?
.
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PCBONEZCommented:
You know... If it's that small you can get a better one with a quick trip to the dollar store..
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cboydaAuthor Commented:
PCBONEZ:
Double wire to split, then Y is two single wires.
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PCBONEZCommented:
You should go with a T shape, as in the two upper sections of the wye should form a straight line.
The ideal length across the top would be 4' 9". (The closer the better).

You are trying to physically create a straight line that is a fraction of the wave length you want to capture.
Meaning a harmonic.
4' 9" results in a harmonic frequency in the middle of the FM frequency range and should be close enough to get reception all the way from the upper to lower end of your FM dial. ( FM dial? ... Damn I'm old...).
.
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PCBONEZCommented:
I think you are better off just buying or building a better antenna.
As that is only one wire across the top it's not even a proper antenna.
There should be two wires across the top and they should be connected to form a flattened loop as shown in the link I posted.
Your body is basically increasing the surface area of the antenna and bigger antennas work better because they collect smaller signals.
You might consider adding a length of wire and connecting to each end of the T.
But that's almost as much trouble as building a new antenna out of some flat 300 ohm antenna wire.
.

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ridCommented:
If the radio signal is weak, you need to exercise some care in making the antenna. The proper length, as described above is one important part. Impedance matching is another, as well as placement of the antenna.

If you make a "T" shaped antenna, the impedance of the thingy is about 150 ohms, and the cable that goes from the "T" to the receiver needs to match this and so, ideally, should the receiver antenna input. If the input is a coax connector, it may unfortunately be 75 ohms, which is not ideal here. In fact, I think you might do well to pay a visit to a local radio store (or something of that description) and tell them your story. They should be able to furnish you with connectors, transformers, cable and even an indoor antenna that will give satisfactory signal level without a human body being involved.
/RID
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PCBONEZCommented:
Hey,,, This is fun...
http://www.1728.com/freqwave.htm

If you have room on your wall you can use that link I sent before and use the 300 ohm antenna wire but make the top bar a full wavelength for 98MHz. (About the middle of FM) (And less 5% length, it's an engineering thing.)
~ It will much recieve better. (9.5 feet long is about perfect.)
The length of the 'tail' doesn't matter so make it long enough to mount it (with push pins) as high as you can get it.
If you need to get from 300 ohm wire to a 75 ohm coaxial jack use one of those adapters used for old TV's.
(Dollar store itme.)

And if you'd rather spend money than time you can pick up an AMPLIFIED antenna (yes, 'amplified' rabbit ears) at radio shack / walmart / kmart / where ever they sell TV's / home depot even has them / .. for around $20 if you shop. (I've seen them for $12 but that was a local one-off store.) - If it doesn't have a wall transformer or batteries it is NOT amplified. I don't care what the package says.....
The trick for using rabbit ears for FM instead of TV is to only extend the ears such that the total length of both is about 4' 9".
.
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cboydaAuthor Commented:
Just a couple closing comments.

The receiver actually says 75Ohms, and I ended up using an old set of TV (non-amplified) rabbit ears.  Works great!

Just a little ugly but hey.. I got reception :)
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