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Discussion in 'Communication (CB | GPS | HAM)' started by afroman006, Apr 10, 2003.

  1. afroman006

    afroman006 1/2 ton status

    Aug 21, 2002
    Likes Received:
    College Station & Kingsville, Texas
    What are sidebands? I was checkin out some radios on Cobra's site and the most expensive one had upper and lower sidebands, what are they? Thx
  2. rebelk5frk

    rebelk5frk 1/2 ton status

    Dec 29, 2001
    Likes Received:
    Houston, TX
    Without getting too technical...SSB (Single Side Band) radios have 3 modes AM Upper side band and Lower side band. Basically an AM transmission has 3 parts. A "Carrier" plus an "Upper" and "Lower" side band. The "carrier" doesn't have any information (in a cb's case Audio) It is just a "reference" for the receiver to lock onto so the reciever knows where to look for the "side bands" The actually information (voices) your hear are in these "side bands" Radio guru's long ago figured out that for simple voice communication you don't need the quality of having BOTH "side bands" to understand the message.

    A SSB radio when in "Upper side band" or "Lower side band" mode filters out the unneeded side band and carrier and only transmits and receives the selected side band.

    What is the point in all of this? SSB is more efficient. It takes the power that would normally be split 3 ways and combines it all into one. In theory that will give you 3 times the power of a normal AM transmission. It also limits the receiver bandwidth making it a little more difficult to tun in but makes it easier to seperate the desired station from the static.

    If you have a SSB radio such as the Cobra 148 the USB or LSB will only work when listening to or speaking to other stations with the same capabilities and are in the same mode you are in. If you aren't in the same mode as the person you are trying to hear then it will be all garbled. If you have a regular AM cb try tuning to channel 38 sometime where there is a lot of static/traffic on the band. It will probably sound like a lot of garbled speech or like donald duck. That is because ch 38 Lower Side Band is one of the most popular channels for SSB operation.

    With a SSB radio you can also talk on the same "channel" as other people so to speak. AM will normally wipe out a channel but if you find someone talking on say the "lower side band" of a given channel then you could carry on a conversation on "upper side band" of the same channel with someone else at the same time. As long as the stations aren't so close to each other that they "splatter" over to adjacent channels then both sets of conversations can go on at the same time.

    Hope that made some kind of sense to you.

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