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Stupid questions thread.

  • 25-05-2023 9:57am
    #1
    Registered Users, Registered Users 2 Posts: 14


    Hello, new to the hobby, have lots of questions that I'm not getting answers for from Google (possibly through my own fault).


    Is there any experienced Hams (if that's the right term) on this board that would have the time (and patience in fairness) to participate in a "Stupid questions" thread where people like myself could ask about things we don't understand to try and get a simple answer?


    Hopefully there will be an appetite amongst some members here


    Thanks in advance


    JD



Comments

  • Registered Users, Registered Users 2 Posts: 63 ✭✭4dxc


    Just post them and you`ll see. Happy to give some advice if I can.



  • Registered Users, Registered Users 2 Posts: 14 DjAngleGrinder


    OK, first stupid question:

    Is the dipole antenna the best antenna to transmit and receive long range?

    The dipole is to be half a wave length long correct? So if I want to listen on the 2 metre band, should each "arm" of the dipole be 50cm long?

    The scenario in this case is trying to transmit and receive from two points that are unobstructed in terms of line of sight but are 40 km apart.

    Can I make a dipole out of 2 bits of wire and coax or is a Balun essential?


    Ty in advance



  • Registered Users, Registered Users 2 Posts: 63 ✭✭4dxc


    >>Is the dipole antenna the best antenna to transmit and receive long range?

    A Yagi or a Quad would be a better choice. Depending on the frequency you might want to look at vertical antenna as directional antennas get quite big on 1.8-7.1 Mhz for example. For a beginner a Dipole is a great start.

    >>The dipole is to be half a wave length long correct? So if I want to listen on the 2 metre band, should each "arm" of the dipole be 50cm long?

    Roughly, yes. To calculate the length of each leg you use (300000/Frequency in khz) /4. In the 2m example it would be 300.000/145.600 = 2.06m. As it`s a half-wave diople each leg is 2.06/4 = 51.5cm. Depending on the type of material you use you need to include a velocity factor. If you cannot measure you could start of with a velocity factor of 0.95 which means each leg would be 0.95x51.5cm = 0.49cm.

    >>The scenario in this case is trying to transmit and receive from two points that are unobstructed in terms of line of sight but are 40 km apart. Can I make a dipole out of 2 bits of wire and coax or is a Balun essential?

    I doubt a dipole will work reliably for this. You might want an antenna with more gain (Yagi). Yes, you can feed the dipole directly. However, a balun is recommended to transform the unbalanced coax to the balanced dipole.

    For 2m you have to be already quite precise as tiny deviations quickly result in an antenna thats not resonant on your desired frequency. I am only transmitting on 30Mhz and below where it`s not that critical. Maybe someone who is more experienced on VHF can give you additional tips.



  • Registered Users, Registered Users 2 Posts: 1,877 ✭✭✭BENDYBINN


    Who owns the internet?



  • Registered Users, Registered Users 2 Posts: 14 DjAngleGrinder


    Thanks for that, I'm gonna research Yagi antennas, I'll be back with more drivel soon.



    Zark Muckerberg



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  • Registered Users, Registered Users 2 Posts: 1,877 ✭✭✭BENDYBINN




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