stupid question about what "2 meter" and 70cm bands mean VS freq.

Discussion in 'OnBoard Electronics & Controls' started by Squidly-Diddly, Mar 19, 2017.

  1. Squidly-Diddly
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    Squidly-Diddly Senior Member

    https://www.youtube.com/watch?v=bFC1quZJGs8

    I've got some vague idea that freq = speed of light/wave length, and that by some electronic wizardry a little radio can broadcast on a wide range of freq without needing to physically shorten or lengthen its antenna.

    So what do they mean when they say this radio is "2m and 70cm"?

    Any good links to radio basics? I just got my HAM lic but I'm not getting a few concepts.

    I've got time to watch youtubes but not time to join any clubs at the moment.
     
  2. jehardiman
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    jehardiman Senior Member

  3. jehardiman
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    jehardiman Senior Member

    Sorry, didn't realize the actual question. Basically the discussion of wavelength for a particular xmitter/receiver is more in line towards the antenna size/length than the frequency. All xmitters are tuned for a particular frequency and are expecting a particular sized antenna for maximum effect. Receivers are more tolerant but suffer from gain effects. Sorry, but antennae design is a little out of my field.

    https://www.electronics-tutorials.com/antennas/antenna-basics.htm
     
  4. philSweet
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    philSweet Senior Member


  5. CDK
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    CDK retired engineer

    It is very simple. For maximum performance an antenna must resonate at a particular frequency. If you are satisfied with less than maximum and/or want a shorter antenna, a coil is added in the base, if you want to cover two frequency bands, two different coils are added.
    In your example the radio works reasonable well in the 2 meter and 70 cm band.
     
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