Antenna stacking

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by LA1ZN, Jan 14, 2019 at 10:02 PM.

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  1. LA1ZN

    LA1ZN Premium Subscriber QRZ Page

    Attached are two pictures of my antenna's,
    The lower one are A-3S Cushcraft and the one on top are unknown--- (got that used when I bought the used Tower ) ---- The top one is working very well on 40 m,but the A-3S is not doing too much ----I had the 40 m add in on that antenna, but doesn't do too much.?
    The spacing between them are approx. 3'------and Tower is on this picture approx. 40 ' up.
    Have a feeling that these two Antennas are interfering with each other ?
    Maybe just use one of them ?

    Any suggestions are welcome.
    73 JAN -- W2JAN --- LA1ZN
     

    Attached Files:

  2. W1VT

    W1VT Ham Member QRZ Page

  3. LA1ZN

    LA1ZN Premium Subscriber QRZ Page

    Thanks for feed back -------Can I put these 2 antennas in paralell , maybe ?
     
  4. W1VT

    W1VT Ham Member QRZ Page

    Antenna modeling is one way of handling very close spacing, but it may not be practical with an unknown antenna on top of a tower that works well.
     
  5. KM3F

    KM3F Ham Member QRZ Page

    Doing traditional combining, you can't get them far enough apart on 40m on the same tower to make a worthwhile difference and have to uses Q sections to get them to 50 ohms.
    Can't just Tee two antennas together. 50 to 50 = 25 ohms an SWR of 2 to 1.
    The Q sections are needed to get back to 50 ohms at the Tee point.
    Normally two identical antennas offer a gain of just under 3 db.
    These two, being quite different and close spaced isn't worth the effort and destroys any pattern one beam normally would have..
    3 db is normally given as 1 S units and you can't get them far enough apart for stacking.
    With what you have in the air now, I would consider single mono band 4 element and get a performance result far greater than what you now have and no stacking issue.
    Ever hear the Italian station that comes in at 10 and 20 over 9 on 40m? He uses a 4E mono plus power.
    Good luck.
     
    Last edited: Jan 15, 2019 at 4:11 PM
    LA1ZN and NH7RO like this.
  6. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    I don't know what the upper beam is, either, but that's a very light-duty tower for two HF beams!

    Hope you leave it "cranked down" in the wind.:)
     
  7. LA1ZN

    LA1ZN Premium Subscriber QRZ Page

    Thank you for feedback -----
    I have heavy duty guy wires on the Tower , since this picture was taken ----and so far no issue with the wind-----, but I normally take it down if it will be heavy wind for a longer time.

    I will look into a 40 meter monoband ..or a dual band for 20 and 40 -- will research

    Also I will remove the upper ant. and see how it will work with only the A3s


    JAN
     

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