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Radio scanner Citizens band

Discussion in 'Receivers and amplifiers' started by Jozza, Feb 15, 2007.

  1. Jozza

    Jozza Member

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    I want to fix an old FM Citizens Band radio scanner of mine. Its a Sharp 40 channel. Would anyone here be able to give me some technical help?
     
  2. behrad

    behrad Regular member

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    wow that is possible the most open ended question ever.

    Well, i will try. Please ask your question(s)?
     
  3. Jozza

    Jozza Member

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    Sorry!

    Well I got it powered up, but the signal gauge is not moving until I press the switch to talk. Then it dies when I let the switch go.

    Could it be the antenna? I hooked up a tv antenna to it.
     
  4. gerry1

    gerry1 Guest

  5. kapooty

    kapooty Member

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    You are not yanking our legs are you on this one? It sounds to me like its working, or it was. First of all a CB radio is either AM or Single Sideband. I never saw one that was FM. 40 channels is a newer rig. First of all #1. do not operate the radio without a load. Meaning it needs an antenna for that frequency and not a tv antenna. If you dont the chances of it being ruined is very good. The reason why i think you were yanking our legs is you knew what the push to talk button was for. If this has an AM/SSB switch and you place it on AM, when you push the button on the mic the power needle should go up and wiggle a little at top end when you talk. This proves that you have power going out and modulation,(your voice is going out on the signal). So assume the transmitter works ok. When you let go of the button you are then in the receiving mode. Turn the "RF GAIN" control all the way to the right if you have one, this controls the amount of signal from the other station you are tring to receive. So turn it all the way to maximum, so it will be receiving at full power. Now turn the squelch control until you hear it going shhhhhhhhhhh. Hopefully the volume control is turned up as well. Usually the squelch is adjusted just until the shhhhh noise goes away. When you receive a signal from another transmitter, it should break the squelch so to speak and you should hear them. Now if you have a SSB mode on it, when you talk the needle should go up and down ratically, and if you dont say anything at all the needle wont move. To receive and hear the other guy, you will need to turn the BFO or VFO knob slowly until their voice sounds like a normal voice. A homemade antenna can be made with wire or aluminum tubing from broken tv antennas
    I drew one for you here http://www.yourownfree.com/downloads/cb-antenna
    This is a 1/4 Wave Ground Plane Antenna for CB Radio, yours is a CB radio, operating in the 27 mHz frequency range and not a scanner.
    If you want an antenna for a scanner then make the wire lengths only about 19 inches long for a frequency of about 146 mHz - 180 mHz
    Use the formula 234/ Frequency in mHz
    A – E can either be wire or aluminum tubing
    A is ran vertical and B- E are at a 45 degree angle going downward
    So-239 is a female connector you can get at Radio Shack, it looks like the one on the back of your CB radio
    Be sure and use 50 Ohm coax cable and not TV cable
    You can get the coax cable at Radio Shack, make sure you tell them it’s for CB radio
    Wire A is soldered to the pin on the SO-239 connector
    Wires B – E are fastened to the plate of the SO-239 connector and constitute the ground plane. Hope this helps

     

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