short wave radio question

Discussion in 'Communications' started by bstickler92, Sep 8, 2010.

  1. bstickler92

    bstickler92 Well-Known Member

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    i've got an old radio that picks up short wave, doesn't pick up much here in morgantown but when i did pick some thing up, i let go of the radio and the station went away.

    so my question is why is it that radios perform differently when you're touching them or just generally around them?
     
  2. NaeKid

    NaeKid YourAdministrator, eh?

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    I have noticed that as well about certain radios.

    I believe that our bodies can be used as part of the antenna system to focus the radio-waves a little better, almost like the dish-effect for satellite systems. Of course, someone smarter than myself will chime in soon .. ;)
     

  3. bstickler92

    bstickler92 Well-Known Member

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    you think it has something to do with our water content? i know water can shield some waves but amplify radio? it's hard to believe or i'm just making it up, again, hopefully someone smarter than i will chime in
     
  4. The_Blob

    The_Blob performing monkey

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    radio waves, like all EM radiation (including light), treat materials differently based on their wavelength; some will be opaque, some will be transparent, some will possess different degrees of reflectivity etc etc ad nauseum...

    idk what frequencies SW bands are off the top of my head (20kHz~25mHz?)

    I don't think that is a high enough freq to interact with water molecules in a manner that causes a resonance amplification effect (think of a door that is open with music playing in the next room, then closing the door partially & certain frequencies of sound appear louder to to accoustic amplification)

    I'm pretty certain that it's a combination on absorbtion/reflectivity &/or increase in surface area (especially when touching) the antenna

    you could have a bad ground loop if it's "static-y"

    I personally would take a coil of insulated wire & attach it to the antenna terminals & hang it out the window (or on the wall).
     
  5. 101airborne

    101airborne Well-Known Member

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    Basically when you are touching the antenna on a reciever, such as SW and AM radios you get a stronger signal because you are acting as a larger antenna. Most SW and AM signals are broadcast on a "weaker" frequency or power than say FM channels. Therefore needing a better antenna to pick up distant stations. Try moving the radio closer to a window or somwthing or as someone else sugested try running a "string" ( piece of wire) antenna from the radio antenna along the wall or around a window to increase the area to "catch" the signal. I have done this myself and had greater reception not only in "found" channels but helped find other channels as well.
     
  6. bstickler92

    bstickler92 Well-Known Member

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    thanks oldsoldier, the radio i'm using is on the other side of the room from the window but i'm up pretty high(5th floor res hall) but there's 3 other towers blocking signal. would proximity to tall solid buildings reduce reception too? i'm in a small concrete walled, ceilinged, floored, room (college dorm)
     
  7. 101airborne

    101airborne Well-Known Member

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    I'd say yes as the towers are likely concrete and steel they will absorbe or deflect the signal to and extent. Try this and see what happens move the radio directly in front of the window and check your reception, if it improves then try using some type of wire, speaker wire works pretty good and run a loop around the inside of the window if you can't open the window. If you can open it dangle 4-5' out the window and connect the ends to the radios antenna, making a crude loop antenna. That should help your reception quite a bit. If not you may just be in a signal dead zone. Do you have good signal on other things like cellular phone, fm/am radio and such?
     
  8. bstickler92

    bstickler92 Well-Known Member

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    fm radio is pretty good, i'm about 2 miles north of morgantown, wv so mountains are plentiful. cell is great for me because the res tower to the NE of me has what cell phone towers have on the roof. i would do the wire thing, i've got a roll of 16 guage i used for auto lighting but i don't think my roommate would take kindly to me running wires through his stuff. i'll try the window trick tomorrow because it's been storming pretty bad tonight and i don't feel like trying for a signal now. if i were to do the dangle wire out the window, would i just extend the antenna on my radio or would i have a loop going out the window from the antenna and back to the antenna?
     
  9. 101airborne

    101airborne Well-Known Member

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    If your radio has the screws on the back for an external antenna hook them up to those. Making a loop, if not you can drop the wire out the window and connect ends to existing antenna, you should extend the standard antenna that and the wire will give you the effect of a larger antenna.