Back to back yagis, how to connect?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by LZ1MAK, Jan 14, 2015.

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  1. LZ1MAK

    LZ1MAK Ham Member QRZ Page

    Last edited: Jan 14, 2015
  2. AA9G

    AA9G Ham Member QRZ Page

    There is no point to this. A yagi antenna does not magically create more power (gain) out of thin air. It takes the available power and focuses it in a given direction. If you send 100 watts up the line to one yagi you have 100 watts largely focused in the direction the yagi is pointed, dependent on number of elements and boom length. If you send 100 watts up the line to FOUR yagi's you DO NOT get 4 antennas focusing 100 watts each. You get antennas focusing 25 watts each and you don't even get as much effective power out because you have also introduced more line loss and other inefficiency than you have with one antenna.
  3. W6RZ

    W6RZ Premium Subscriber QRZ Page

    More likely it's a rotator-less contest station. A 4-way antenna switch at the operator position is almost instantaneous compared to a rotator.
  4. KH6AQ

    KH6AQ XML Subscriber QRZ Page

    I believe the link refers to feeding one Yagi-Uda at a time and not all at the same time.
  5. N2SR

    N2SR Ham Member QRZ Page

    If you have 2 or more yagis pointed in the SAME direction, you WILL get a power gain. If you stack two yagis a specific distance apart, have them at specific heights, and phase them correctly, you will get something like 2.6 dB more gain.

    That is why big contesters stack yagis. That is why HFTA is a valuable program for contesters (and anyone else planning a tower installation).

    Stacking antennas also "combines" lobes, and if those yagis are stacked correctly, it will give you one big fat lobe (at specific elevation "from - to"). If those elevations are in the range of arrival angles of signals from various parts of the world, you will minimize QSB. Arrival angles differ for various parts of the world. "Long haul" DX is typically at a lower angle, so being able to switch the stack between LOW, HIGH or BOTH is good.

    If you look at a typical elevation plot for any antenna, there are nulls. If the arrival angle of the signal ends up in a null, either you won't hear the other station, or you will encounter QSB.
  6. AA9G

    AA9G Ham Member QRZ Page

    I know that. The OP is not talking about pointing them in the same direction however.
  7. AC6S

    AC6S Ham Member QRZ Page

    Every time I see that avatar it reminds me "oh yeah, I need to run a duster between the radio gear".

    Back on topic.
  8. KC9VFO

    KC9VFO XML Subscriber QRZ Page

    What if a person properly phased a couple of yagis pointed in different directions...wouldn't that work??? I personally phase my 2 meter yagis in the same direction and use a rotator.
  9. AC2FO

    AC2FO Premium Subscriber QRZ Page

    I don't see any back to back yagi's in that picture

  10. G7FQW

    G7FQW Ham Member QRZ Page

    Why not use 8, each 45 degrees out and then you would not even need a rotator :) :)
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