Big Loops. What is the point of diminishing returns?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by K0MBT, Nov 30, 2018.

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  1. W1VT

    W1VT Ham Member QRZ Page

    I worked a fellow running 20 watts to a "dummy load" antenna. I may have been his best DX on 160.
     
  2. K0MBT

    K0MBT Ham Member QRZ Page

    I usually find that 20m works the best. Occasionally 40. My radio goes 80-10.
     
  3. AA5CT

    AA5CT Ham Member QRZ Page

    Was this "dummy" load at the far end of a pair of wires common called a Rhombic? Could feed a primary wire on a power pole - make it half a Rhombic against ground ...
     
  4. K0MBT

    K0MBT Ham Member QRZ Page

    I have to admit that i have been more than a little impressed in this version of the loop antenna. The GEFW is working great.

    When we rebuilt this antenna switching from insulated copper wire to Galvanized electric fence wire (laying on the tops of trees and stretched across the pasture), I thought that we were going to be met with attenuated signals. That is what the math implies. But the antenna is quieter but receives and transmits better than the previous loop.

    It's tough to do A-B-A type of testing as the other antenna was destroyed by ice.
     
  5. K2XT

    K2XT Premium Subscriber QRZ Page

    I was about to ask how you know it performs better, but then you answered it yourself.
     
  6. AD5MB

    AD5MB Ham Member QRZ Page

    ( if this makes no sense it's not meant for you )

    Trained as a 33D10, "promoted" to a 33S1H by some clerk 6 weeks before ETS. Sinop '74 - 75. Ft Darvon instructing 33D 75 - 77.

    15 years at a NASA tracking station. 5 Lightning Fast Chicken Plucker coworkers out of a hundred. And 2 Marine E9s - such pleasant people.

    I don't even try to tell people what that means. Way too much experience with people too small minded to believe it.
     
    AA4TG likes this.
  7. K0MBT

    K0MBT Ham Member QRZ Page

    Know exactly what you are talking about ad5mb I was up in the turkey herder area in 70-71
     
  8. K6LPM

    K6LPM Ham Member QRZ Page

    Yes I have. It is a pita
     
  9. WA7F

    WA7F Premium Subscriber QRZ Page

    Wow, I posted that a while ago. So it was a PITA. Did it work?
     
  10. K6LPM

    K6LPM Ham Member QRZ Page

    Negligibly. I had my delta loop anchor points using plastic clothesline pulleys as insulators and whole antenna could free float. Moving feed point did in fact make noticeable but inconsistent patterns in the angle take off on 17 mtrs using a 250 ft inverted Delta sloper. I raised and lowered corners and also narrowed it. I could seemingly get a 90 degree null from North to East back and forth depending on which of two corners I lowered. This was more regularly observed but required lowering all three corners and opening the loop to pass the feedpoint past the other side of pulley/insulator/ anchor point and then re raising the other two corners. I got it down to doing it in about 10 minutes including resplicing the feedpoint. My observations we're far from scientific and very inconsistent as was the mechanics of the antenna too. But showed promise but not enough promise to build a more dynamically effective mechanical system.
     
    W1TRY likes this.

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