FM Antenna question

Discussion in 'Beginners, General Questions' started by EricTut, Oct 24, 2003.

  1. EricTut

    EricTut Extra

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    Hi all-

    I recently got an Onkyo TR-600. Been great for TV/movies, so so for music. That may be my speakers prob though, onkyo HT500s. At any rate, it comes with this 22 guage cable, maybe 4 foot long, to use as the FM antenna. PLugs into the center of what looks to be a coax plug in, per the instructions. Soo...

    Are those $25 powered FM antennas on sale at home depot any good, or a waste of money? Mind that this is really only for background music, but still, reception is (surprisingly) crummy with the 22 guage noodle it shipped with.

    Curious, and TIA

    Eric
     
  2. Ted Lee

    Ted Lee Lead Actor

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    i don't remember my exact setup now, but i know when i was in high-school i had a fm amp hooked up to my system. however, i think i had it routing something like this?

    wall (75-ohm) -> fm amp -> tuner

    luckily, i had the coax connection in my bedroom, so that made it easier. but i know you can also hook up those 22g fm antennas to an amp - you may need a 300-ohm (?) adaptor though.

    anyway, it certainly can't hurt to try. i think the only problem you may have is with local stations - you may "overpower" stations that are nearby on the dial.

    what the heck...since it's home depot...if it doesn't work just take it back!
     
  3. Tim K

    Tim K Second Unit

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    I had one of those a while back...still do as a matter of fact. It sits in the closet under the basement stairs in a box. I have a thin noodle attached to my receiver. I found, at least 3 years ago when I last used it, that a single wire gets as good reception as the powered antenna did. It was a pain to have to get up to tune the antenna for every channel. Maybe technology is better now...maybe I was in a bad location.

    How about this...I'll try it again and post my results!

    -Tim
     
  4. EricTut

    EricTut Extra

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    Thanks guys, and thank you Tim for running that experiment for me.

    Heres another thought- what if I replaced the noodle with a length of coax? Would that be better?

    Heck, I could even plug it in to an unused run of coax in my house, that would add at least 50 feet to the run. Hmm..

    Is it possible to hurt my amp by trying? Its a passive antenna input after all.

    TIA, again

    Eric
     
  5. Tim K

    Tim K Second Unit

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    Eric,
    I currently use about 6ft of speaker wire as my FM antenna and its better than "the noodle". I'd think 50ft of coax might be even better, as long as the coax isn't connected to anything at the other end.

    I'm going to head upstairs and try my powered antenna. I'll post my results soon.
     
  6. Tim K

    Tim K Second Unit

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    Here are my completely unscientific results.
    I rated reception out of 10, with 10/10 being clear stereo with NO static, 5/10 was barely tolerable with alot of static (As in, if you were stuck in your car and had to listen to your team's football game you would suck it up).

    First, I just tried 10 stations with my regular 6ft speaker wire draped over my entertainment stand

    93.3 - 10/10
    94.1 - 8/10
    95.7 - 6/10
    96.5 - 5/10
    97.5 - 7/10
    98.9 - 9/10
    100.3 - 8/10
    102.1 - 6/10
    102.9 - 10/10
    103.9 - 6/10

    Second, I hooked up the powered antenna. This thing has a little dial that you can adjust to try to fine tune the frequency you are pulling in. I tuned to the station, then adjusted the dial to get the best reception I could.

    93.3 - 10/10
    94.1 - 8/10
    95.7 - 8/10
    96.5 - 8/10
    97.5 - 8/10
    98.9 - 10/10
    100.3 - 10/10
    102.1 - 10/10
    102.9 - 10/10
    103.9 - 6/10

    To be fair, I then went back to my ghetto wire antenna, and tried to fine-tune each station. That meant moving it around to different positions. Quite a pain in the butt as I don't know how I would arrange to make the wire stay in position. I guess if you have kids you could make them hold the wire! Here are the results.

    93.3 - 10/10
    94.1 - 10/10
    95.7 - 10/10
    96.5 - 10/10
    97.5 - 10/10
    98.9 - 10/10
    100.3 - 10/10
    102.1 - 10/10
    102.9 - 10/10
    103.9 - 8/10

    In conclusion, it depends. If you have pretty poor reception with the noodle/short wire antenna in a set position, you have two choices which will give you about equal results...it just depends on what action you want to take. Both require you to get up off your butt which I don't want to do.
    1) You can adjust the position of the antenna for every channel.
    2) You can use a power antenna and fine tune the frequency for every channel.

    Eric, maybe you could give us the results of your coax experiment??? I may try hooking up a longer section of speaker wire.
     
  7. Ted Lee

    Ted Lee Lead Actor

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    nice test tim. it's nice to see people actually do some personal testing before typing. at least then they have evidence to back their claims. [​IMG]
     
  8. Larry Alan

    Larry Alan Auditioning

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    Hi Eric,
    I just installed an FM antenna that really blows me away how well it works. I too received a short wire for the FM antenna on my new HK avr 230. The wire only got me a few stations. I had an old Rat shack S shaped dipole antenna in my attic that did not work well and has been sitting there for 20 years. I installed it on a piece of pipe that is an extension of my bird feeder pole, which gets it about 18' off the ground.
    This antenna, that did not work in my attic, is now outside and works SUPER!!!! I can get stations from most directions out about 50-60 miles. It must be a omni directional design to be able to get so many stations from different areas but I cant believe this 6 oz., 3', S shaped wonder, is so great in my poor receiving location.

    I think the key is to get the antenna outside. The coax by itself is deaf. The outside antenna is the answer. A friend installed a automobile antenna on the roof where he works and it works well for him.

    GET IT OUTSIDE!!!

    Larry
     
  9. EricTut

    EricTut Extra

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    All-

    I am amazed at the response this thread has gotten, thank you! I think I will...

    Jumper the coax to the house line, then I have a run straight out to my coax junction box, where I can rig an outdoor antenna. Nobody will be the wiser, I am in arizona where the lazy bums put all your service demarcs in the same spot, along with your fuse box. It would be hard to tell an antenna apart from the meter and other crap out there.

    Again, thanks for the suggestions!

    Eric
     
  10. Iver

    Iver Second Unit

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    Coax itself would probably not work well as an antenna since, by design, it carries RF without allowing any RF to penetrate from the grounded outer braid to the inner signal-carrying wire. This is if we're takling about a configuration where you connect the coax in the standard fashion (using an F-plug to F-jack on a typical 75-Ohm FM antenna connection on a receiver or tuner), meaning the outer braid is grounded and the inner wire connects to the little prong (the one where the freebie antenna that came with your receiver connects).

    The exposed inner wire at the very end of the coax cable could pick up signals, but this would not work much better than the reception you get with no antenna connected to the antenna jack (the metal component itself will pick up signals if they're strong enough), except that you will likely have the end of the coax cable in a better position for signal reception.

    With unshielded feeder lines, such as 300-Ohm twin lead, or even speaker wire, the line itself can function as an antenna.

    If you have an outdoor TV antenna, you can split a line off the line from that and use it for FM. Ideally, you'd want the TV antenna to be optimized for the FM band, but any outdoor antenna will give you better FM reception than a simple wire antenna installed indoors.
     

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