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Minimax Antenna discussion

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by N4ISF, Sep 3, 2011.

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  1. N4ISF

    N4ISF Ham Member QRZ Page

    I will start a thread for discussion. Even though I'm building them, doing it with detailed instructions from Tom and using his antenna analyzer, I am just trying to learn about them myself so I don't have all the answers.

    I know very little more than what is on his website;

    But I can call Tom with questions.
  2. W0BTU

    W0BTU Ham Member QRZ Page

    I glanced at that site, and I see no diagrams or technical explanation of how they work. Am I missing something?

    Do you have a schematic or diagram?
  3. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    The other thread about small business for ham gear didn't allow much commentary but I had asked a question there that wasn't answered: You said you adjust each antenna using an analyzer, etc. and I asked "What do you adjust?"

    It would be interesting to know what you're actually adjusting, that would tell us a bit more about the design.
  4. KB9MZ

    KB9MZ Ham Member QRZ Page

    My first point of interest was that it was an April publication.
    The second point was that a patent was applied for, at least I thought it said that.
    So why is information being with held as the construction details are most assuredly available
    from the PTO. The third point of interest was that it didn't need a ground plane which
    would mean that it is either shielded or alternatively a full WL. Yes, it could probably work in some fashion
    but fashion usually only lasts for less than a year.I like the idea of trying for a better antenna but is better best
    and best at what.I am personally waiting to see what congress is going to do with respect to patent laws as they are not only lazy
    but in their search for money to spend they robbed the PTO of all its funds and didn't leave them enough funds to do their job
    Congress immediatly fiddled with the existing rules that allowed first to file as the owner even if they were stolen goods. Now they intent to create
    commissions to determine if applications given could be later revoked.Still congress is made up of the peoples wishes so we will get what we deserve.
    As for Tom W8JI I assume he is stuck on a new antenna structure somewhere in a World of his own to prove big is better and better is best!
    I guess the whole thing is a April one article until more info is more forth comming
  5. KB9MZ

    KB9MZ Ham Member QRZ Page

    This thread challenges the credability of QRZ. Is is just a clumsy product of a child.
    Some may not see any harm in such a poor joke but this forum is meant to help
    newbies with questions on radio and when such garbage is allowed to be posted it removes any confidence
    from a newby with respect to the integrity of responses given. In fact it is a disservice to the hobby of ham radio.
    If Tom W8JI has involvment in this posting then shame on him. If his name was used without his consent then I am quite sure that Tom can deal with the joker.
    Art Unwin KB9MZ
  6. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    To me, the photos of the antenna looked like an "E-H" antenna, which has been around for a long time; however without any details, I can't tell for sure.

    That's why I asked, "What are you tuning?"

    If the question remains unanswered, then this is all a hoax.
  7. W3PO

    W3PO Ham Member QRZ Page

    It seems to me like another whiz bam.
    In the light of these miracle antennas I always point to W4RNL article on how to market an antenna
    Spend a few minutes, great read.
    73 de Pat w3po/vq9po
  8. N0AZZ

    N0AZZ Ham Member QRZ Page

    Tom has always been a person that I looked to for many antenna questions and many of his designs are copied and sold like the DX Engineering kits very nice ones.
  9. VK6ZGO

    VK6ZGO Ham Member QRZ Page

    Different Tom,Art!

  10. VE3FMC

    VE3FMC XML Subscriber QRZ Page

    I think you have mistaken Tom W8JI for Tom KE4LH , the builder of the antennas.
  11. G3TXQ

    G3TXQ Ham Member QRZ Page

    It's a good job Tom (W8JI) is alive and well - otherwise I reckon he'd be turning in his grave that someone thought he was the designer of that antenna ;)

    Steve G3TXQ
  12. KB9MZ

    KB9MZ Ham Member QRZ Page

    The design CANNOT be pending under the "first inventor to file" as that PTO change is not yet in effect.
    It is due to be discussed in the house later this month and based on the history in congress it may never reach the president for signing.
    For those who consider connecting a radiator directly with a 50 ohm coax when its it has a impedance in the three figures then it is no wonder that hams
    of the present day are released from their earnings
    And yes there are many more "toms" than W8JI so it could be anybody.
  13. N4ISF

    N4ISF Ham Member QRZ Page

    There is a loading coil which I'm adjusting to tune them. Every one ends up just a little bit different. The design calls for a certain number of turns for a certain frequency, the first one I built needed 3 less than that, the next one needed 2 less. While I was tuning one my brother walked beside it, and his presence within 4 ft of it threw the resonance off. (it was on a short pole 4 ft high)

    We don't need destructive criticism, will be ignoring it, constructive criticism is OK. This is definitely something still in the experimental stage. It does not fit the normal criteria for antennas, it's acting entirely different, therefore judging it without having used it and tested it reveals ignorance. Like the men who scoffed at the Wright brothers, declaring that man would never get a heavier than air machine off the ground.

    A question was asked concerning grounding, I passed it on to Tom Brent, KE4LH, his reply was;

    "If you ground this antenna it will not work at all. It hates the ground. No ground is required. And because they are insulated there shouldn't be a problem with lightning. You can ground the coax shield at the radio end if you want but putting any kind of ground on this antenna will destroy its performance. This is not a normal antenna.... Think of it as a conduit to space, not a radiating element you read about in a book."
  14. KB9MZ

    KB9MZ Ham Member QRZ Page

    I understand where you are comming from but by stating a patent was PENDING
    suggested that the PTO has accepted your approach to antennas and all construction
    material was in print. The idea of constant equilibrium is well proven in university
    testing but the rest is certainly not acceptable.I applaud your idea of experimenting for
    . change but there was no phenomina that arose that made the antenna different
    I aplaud your experimental attempts with antennas but in searching for improvements you must have a full understanding
    of present design to be able to measure improvement and explane the phenomina that leads to improvement.
    Most millionairs make all the errors possible before landing on the right solution so to be a leader you must go thru the process or be a follower
    of the rest of the talking heads that nod to you from the rear of a car
    Don't give up
  15. K4SAV

    K4SAV Ham Member QRZ Page

    Art, the guy applying for the patent is not posting on this forum.
  16. VK6ZGO

    VK6ZGO Ham Member QRZ Page

    This is a poor analogy.
    The Wright's aircraft was not a completely new concept which purported to be different to all others.It was the evolutionary result of concepts derived & proven by their predecessors.
    Hargreaves,Langley,Cayley or Lilienthal would not have scoffed at the Wright brothers!

  17. W9XMT

    W9XMT Ham Member QRZ Page

    Sorry, but the electrically short, base-loaded, vertical monopole described in this thread is not a new concept in the experimental stage. It has been in use for decades -- such as in land mobile and marine setups, and by unlicensed systems claiming to operate under Part 15.219 of the FCC Rules.

    All monopole systems need a return path for the r-f current they radiate into the ground plane near the antenna. This can be provided by connecting the chassis of a ground-mounted transmitter to a true r-f ground (buried radials or ground rods), or to elevated conductors isolated from the Earth such as the body of a vehicle, or several "counterpoise" wires.

    Unless some means is provided in the Minimax system design to prevent r-f current from flowing on the outside of the coax driving the loading coil, then radiation from the coax easily could exceed the radiation from the resonated monopole considered to be "the antenna."

    The NEC-2D study below shows this effect for one combination of systems. It was done using values consistent with Part 15 installations, but the same principles apply for higher transmitter powers in the HF bands.

    R. Fry

  18. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    It doesn't matter that the antenna is "insulated," the radiator has to be a conductor or it can't radiate. Just a simple whip insulated from its mounting is still a lightning rod, and if its only earth return is at the station ("ground the shield at the radio") then the return path for lightning discharges becomes the radio.

    Not only is that dangerous, it violates NEC which requires that all outdoor antennas have an outside earth return path...
  19. KB9MZ

    KB9MZ Ham Member QRZ Page

    They did a tour of Europe reviewing what other inventors were doing.
    When they got home is when they put together all they had learned and achieved their mission
  20. KE4LH

    KE4LH Ham Member QRZ Page

    I believe NEC only applies to commercial buildings and you are not required as a home owner to ground your antenna. How do you ground your dipole? Isn't that a much worse example of a possible lightning strike with all that wire up in the air?
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