Anyone still running large HF multi-band quad antennas?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by W7UUU, Oct 9, 2019.

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  1. NE1U

    NE1U Ham Member QRZ Page

    I am also loving tilt overs. But given the size of a quad, some planning is clearly needed. First of all, I have never had a quad. So other that the obvious issues (I'm guessing) of bent or broken spars. What else could the be? Said naively and open eyed ... .. .
     
  2. NH7RO

    NH7RO Ham Member QRZ Page

    Maybe get your feet wet with a 2m or 6m quad---a good way to learn how to build and tune one on a much smaller scale. Just a thought...
     
    AA7QQ and W7UUU like this.
  3. KE0EYJ

    KE0EYJ XML Subscriber QRZ Page

    I have thought about trying to build a 2-el wire delta yagi for 20m. Modeling says it will be 1db more than the best 2-el yagi I can make. Problem is, I believe I need a 2 to 1 balun, is that correct?
     
    N8ZI likes this.
  4. N8ZI

    N8ZI XML Subscriber QRZ Page

    I have been building and using quads for 2m/70cm for 15 years and they beat comparable size yagis up to around 10 elements. My 8 element 2m quads are about a full S unit stronger than a Cushcraft 13b2, half the boom length and on long haul contacts the quads hold the signal longer than the Cushcraft. I would like to compare them against a quality M2 antenna.
    Several DX Stations prefer Quads and always seem to have a stronger signal than their yagi buddies down the road.
    Many manufactures still sell quads. Cubex in Michigan and Giovanni antennas in Italy to name a few. Giovanni makes them all the way up to 80m and uses antenna tower sections for the boom.
    In spring I plan on purchasing a Cubex Mantis II that has 4 elements on 10-20 and 2 elements on 30-40. For best performance it will be fed with separate coax sections from a mast mounted coax switch to each element. That only requires 1 coax out the shack and up the tower. Spiderbeam/hexbeam users would also benefit from separate coax instead of feeding multiple bands from one point.
    Quads rule while yagis drool hi hi
     
  5. N8ZI

    N8ZI XML Subscriber QRZ Page

    A square loop has better TX/RX than a delta loop and a round loop is better yet but difficult to construct for HF.
    Why would you need a 2:1 balun?
    There are numerous websites including YouTube videos that will provide detailed instructions. Operators have been using them for decades, all the way up to 160m.
    On the big boy antennas they use relays to switch beam heading 180º since it would be quite difficult to rotate a multi element 160m beam :)
     
    NH7RO likes this.
  6. KE0EYJ

    KE0EYJ XML Subscriber QRZ Page

    Because it doesn't end up a 50 ohm antenna, correct?

    I don't have any experience with delta loops, and the Mmanagal software says they're 90 to 100 ohms or so.. but 1.1 to 1.2 swr. That confuses me, which is why I asked.

    And I'm not sure a quad-style is doable, with the materials I have... hence a delta.
     
  7. N8ZI

    N8ZI XML Subscriber QRZ Page

    Multi element loop antennas like the quad or delta can be built to several feedpoint impedances just like yagis.
    For the loops you have the easier "tried and true" direct feed with 50 ohm coax versions but they have a lower gain and bandwidth. A 75 ohm version has the highest gain and wider bandwidth but requires a matching transformer like you stated. The 125 ohm version has great bandwidth better than the others, is very close to the highest gain of the three and is easily fed with a 1/4 wave matching section of 75ohm coax in series with the 50 ohm.
    I have built many of those 3 designs and the 125 ohm version is by far the best.
    VE3SQB, owner of Degen antennas in Canada has a website with numerous antenna calculating software free of charge. He even has software to tell you how long to make phasing coax, loading coils for verticals and a lot more.
    Build and try out a few easy compact ones for 2m or 70cm then jump in head first and build one for HF. You won't be disappointed :) shoot me an email if you want help or advice. I'm good on QRZ.
     
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  8. KE0EYJ

    KE0EYJ XML Subscriber QRZ Page

    I'd like to, but my roof just isn't big enough on 20m. I'd probably give it a shot for 15m, but I'm not convinced that it's worth it, at least for a few years.

    And a 15m is still pretty darned big.

    I was hoping to find a way to make a delta using my two spiderbeam masts, and just pulling the two bottom corners of a delta, with rope. That would be the easiest way.
     
  9. N8ZI

    N8ZI XML Subscriber QRZ Page

    A 20m loop is only 23.6' a side for a delta and 17.7' for a quad.
    15m is 15.8' delta or 11.8' a side for quad.
    They do not even have to be perfect triangles to work great.
    Yes one vertical support to hold the apex and simple ropes will pull the sides out to form the triangle. Higher is better but even 30' will be fine on 15m or 20m.
    All I have ever used on HF is simple wire antennas and I have 328 countries confirmed. Currently I run a 80m horizontal delta loop on all the bands fed with 450 ohm ladder line into a 2.5:1 balun then 25' of Belden 9913F coax into the shack. I trimmed and pruned it until all bands were below a 2:1.
     
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  10. W7UUU

    W7UUU Super Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    That's what I remember most about the very large Quad my old friend had (WB7QNT, SK) - he was using a 60 or 70 foot crank/tilt tower and would lower the quad into his back yard where he could reach all the important parts with (what I recall to be) a 16-foot step ladder.

    I was only a teenager at the time - but that antenna seemed like the Hindenburg!! - my only other frame of reference was my Mentor/Elmer W7UD who had a Mosley TA-33 up at 90' on a tower not far away.... it seemed so small and "elegant" compared to that giant quad.

    But it doesn't sound like there are all that many "big quads" out there compared to beams...

    Maybe the "Hex-beam" concept finally crossed the two worlds?

    Dave
    W7UUU
     
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