Tune a Magnetic Loop Antenna remotely using WiFi

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by N6JJ, Jun 6, 2021.

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  1. KC3PBI

    KC3PBI Ham Member QRZ Page

    But he gets to build it out of what the working world is made of today. Direct application of skills that are in demand now.
    N6JJ likes this.
  2. K1VT

    K1VT XML Subscriber QRZ Page

    Very nice work Tamir. Your info should be useful for one of my future projects. Thank you.

    Jack K1VT
    N6JJ likes this.
  3. KE5MC

    KE5MC Premium Subscriber QRZ Page

    My last paying gig was a large medical company instrumentation division. Open loop control by step counting is not the stumbling block you think it might be. Mechanically you will have a plus and minus travel limit and a home switch at one end. Every power up will require a homing function to place hardware in a known position. You would have a test position function that would send the motor to the home position and see if it tripped inside a window of allowable error. For the medical instrument many of the axises started the next operation from the home position so a built-in error check was done. The air cap load will likely not cause step loose and motor holding and drive current can be adjusted as needed. I've been out of active design process for a number of years. There were a few stepper motor driver packages with the needed mechanical hardware to computer support. A Raspberry Pi with the multi-function I/O 40 pin connector might be an ideal headless controller at the antenna with its wifi and bluetooth functions. During the design you would not run it headless, but program and control directly.

    The medical instrument I worked on had 10-15 motors. Most were open loop position counting. A couple were shutters using limit switch as stops for open/close position and a few were slot wheel encoder controlled for full time position checking. If encoder count and stepper motor count were to far apart... "Houston we have a problem here..."

    At the end of this post I finally took a look at your GitHub link. I don't do a deep dive, but likely you are well connected into the small board computers and controllers arena. I might have covered something you already know about, but maybe you might reconsider step count positioning. Not likely to be a better 'mouse trap', but learning something new along the path.

    Good job at this point in the journey.

    Good Luck!
    N6JJ likes this.
  4. AK5B

    AK5B Ham Member QRZ Page

    Shazzam! Sorry I am so out-of-touch with today's world! :D

    I built my STL's remote tuning mechanism out of a DC gearmotor, a 6:1 reduction drive, a PWM speed controller (with a little voltage reducer board for the PWM) and a simple up/off/down direction switch in a Hammond box, all current technology, as far as I know---but probably looked at with disdain by younger, tech-savvy Millennials.

    If Tamir's automated STL tuning device floats your boat, fine. To each his own. It's definitely not for me.

    I'm happy with what I applied my ancient skills to way back in 2015, and might build another just like it for another loop that I've been tuning manually out in the field. But tuning manually and listening for the noise peak is fun for me, too, so I may hold off on that for now. I'm in no hurry to have instant, automatic anything, now.

    I don't feel the need to involve a computer or telephone in every aspect of my life like so many do nowadays. I like to build antennas as simply and uncomplicated as I can, and using them thusly helps keep the magic of radio all the more magical to me, too.
    N6JJ likes this.

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