Radio Antenna Theory 101: what they are, how they work

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  • Опубликовано: 20 дек 2024

Комментарии • 26

  • @f.k.b.16
    @f.k.b.16 3 месяца назад +6

    This is a great explanation! I worked for a manufacturing company who wanted to use RFID labels to check if boxes had the correct parts and quantities as they were being shipped. The issue was the parts were large, in large boxes, stacked on top of each other made of half metal half plastic. The antennas were mounted at the loading dock's entrance to the trucks. Between the all-steal fork truck absorbing all the energy and the metal shipping containers turning the antennas into satellite dishes, those radio waves bounced everywhere and were reading parts sometimes 20 feet away but missing parts right under its nose. Both the onsite manufacturing engineers (that put it in and then expected me to get it to work) and the RFID salespeople.. they were both on the same page of a magical perfect world that didn't exist.

    • @ElectronicsNotes
      @ElectronicsNotes  3 месяца назад +2

      Wow, that sounds like a really complicated RF scenario. Normally RFID antennas are made so they provide a very short range for that type of reason. I hope it got sorted in the end.

    • @f.k.b.16
      @f.k.b.16 3 месяца назад +1

      @@ElectronicsNotes 100% Yep!
      After telling our biggest customer it was working, the guy who put it in originally went down every day and counted by hand! 🤪

  • @policedog4030
    @policedog4030 3 месяца назад +1

    Yes, I'd like to suggest Plasma Antennas. The one that I think I saw looked like a fluorescent tube but with a twisted wall shape, seemingly not symmetrical, and the tube appeared pink outdoors in daylight. It stood vertically, and appeared to have a motorized perhaps stepper motor base upon which it could spin. I thought it looked as if the partly spiral shape, when spun, would allow a moving slit in the tube to scan about a five foot vertical beam. I believe it may be a means to view at high resolution inside structures from about 20 meters or more away.

  • @SampleroftheMultiverse
    @SampleroftheMultiverse 3 месяца назад +2

    I am still using my outside tv antenna.
    For some reason my channel 5 signal strength is lower in the daytime and stronger at night.
    I remember when AM station had to follow rules on their Broadcast power based on sunrise and sunset.
    Does the FCC have some rules like that for TV stations?
    5:53

    • @ElectronicsNotes
      @ElectronicsNotes  3 месяца назад +2

      I confess I’m not familiar with FCC regs as I am based in the UK.
      Does anyone else know?

    • @SampleroftheMultiverse
      @SampleroftheMultiverse 3 месяца назад +2

      @@ElectronicsNotes thanks for the response and checking around with your subscribers.

  • @janiceemery2008
    @janiceemery2008 3 месяца назад +3

    Thank you for presenting this simplified form of radio antenna theory. I love it. I am trying to learn as much as I can about ham radio but, the information is so overwhelming. Besides all the theory, I am trying to learn how to solder and put all the wires together. I wish there was a book on putting it all together in a simplified form. I have no electric background so, I am having to learn all that so that I don't blow anything up or ruin my radio. Thank you so very much for presenting this video. KO4UWU

    • @IanPoole
      @IanPoole 3 месяца назад +2

      Thank you for your comment - I really appreciate it. I know that electronics can become overwhelming when you start, so I do try to provide videos that expain the concepts. I am hoping to make a few more in this series before too long.
      Are there any other things you would like me to cover?

    • @janiceemery2008
      @janiceemery2008 3 месяца назад +1

      @@IanPoole Well, let me give that some thought. I have all the ARRL books but reading through them is a little overwhelming also. Someone suggested that I buy The Art of Electronics book. I will give more thought to your question about some other questions I may have. I think sometimes I over think some things. I am going to practice putting ring terminals and power poles on a scrape piece of power cable. In purchasing insulated connectors does it matter what material they are made of? I see a lot of Amazon that are tinned copper and some that aren't. Does this make a difference? Thank you again. One other thing, my elmer gave me a MFJ-4125, do I really need this piece of equipment for running my radio?

    • @ElectronicsNotes
      @ElectronicsNotes  3 месяца назад +2

      Thanks for thinking if there are any other topics you might like me to cover. I am looking at covering some of the aspects of antennas such as matching, impedance, polarisation, etc in more detail.
      As for the connectors, often the part you solder onto is tinned to make it easier for the solder to take. You want to make sure the solder does not flow onto the contact itself. Normally this isn't an issue, but they are often gold plated to ensure the best ohmic contact.
      As for the MFJ-4125, it looks like a rather nice power supply. It could be used to power a transceiver or transmitter running of a nominal 12 volt line. It supplies 13.8 volts at up to about 25 amps. Rather nice.

    • @janiceemery2008
      @janiceemery2008 3 месяца назад +2

      @@ElectronicsNotes Thank you so very much.

  • @johnsonstechworld
    @johnsonstechworld 12 дней назад

    Even though I was seeing your posts on X very often, somehow I missed your RUclips channel! 73 Jon, VU2JO

  • @ricksampson6780
    @ricksampson6780 3 месяца назад +1

    I'm curious on how the various Martian rovers etc are communicating with Earth based receivers.
    I have always been under the impression that interplanetary space is a noisy electromagnetic environment, and the considerable physical distances involved would require a substantial remote transmitter and antenna array.

    • @ElectronicsNotes
      @ElectronicsNotes  3 месяца назад +1

      Yes signal levels are low because if the distances involved. High gain antennas are used at the earth end. Receiver front end noise is one of the main limiting factors on the frequencies used.

    • @ricksampson6780
      @ricksampson6780 3 месяца назад +1

      @@ElectronicsNotes OK, thanks for the comment.

  • @railgap
    @railgap 7 дней назад

    Radio antennas are nothing more or less than impedance matching devices, matching the impedance of your transmission line to the impedance of free space (377 ohms). The E & M fields in the transmission line, around the antenna, and in free space - are the same two fields.

    • @ElectronicsNotes
      @ElectronicsNotes  7 дней назад

      That is certainly one way of looking at antennas.

    • @jonahansen
      @jonahansen 6 дней назад

      This is true, undoubtedly, but only useful at a very abstract level. It's sort of like saying "Humans are nothing more or less than devices that use chemical energy to drive evolutionary adaptions for survival in varied and changing environments."

  • @alanturner1184
    @alanturner1184 3 месяца назад

    said it on X and say it again fantastic easy to follow and understand thank you

    • @ElectronicsNotes
      @ElectronicsNotes  3 месяца назад

      I’m really glad you found the video accessible and useful. Thanks for commenting here and on X.

  • @ReadJohn1421
    @ReadJohn1421 7 дней назад

    John 14:21-23 ESV
    Whoever has my commandments and keeps them, he it is who loves me. And he who loves me will be loved by my Father, and I will love him and manifest myself to him." [22] Judas (not Iscariot) said to him, "Lord, how is it that you will manifest yourself to us, and not to the world?" [23] Jesus answered him, "If anyone loves me, he will keep my word, and my Father will love him, and we will come to him and make our home with him.

    • @ElectronicsNotes
      @ElectronicsNotes  6 дней назад

      While it is good to have faith, this is not a statement that is associated with the video.