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New antenna project...

Discussion in 'Amplitude Modulation' started by N2DTS, Jul 4, 2017.

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  1. N2DTS

    N2DTS Ham Member QRZ Page

    I have had very good luck with my 80 and 40 meter fan dipole, coax fed, low swr at 7290 and 3880.
    No baluns, no traps, just wire and coax.
    I find it very handy to be able to just jump from one band to the other without switching anything or tuning anything.

    I also have a 40 meter dipole that has gone very high in swr, it now seems to have a low swr at some point below 7 MHz....
    So I plan on taking that down and putting up the following antenna:
    Alpha delta LB, its a 160 to 40 meter antenna with coils that sort of act like traps but are not.
    Its only about 100 feet long which is about all the space I have for this antenna.
    I plan on adding 20, 10 and 6 meter legs to the LB to make a fan dipole that does 160 to 6 meters.
    160 is going to be very poor, but it will work well on receive.
    80 is also going to be somewhat poor.
    The coils on the Alpha Delta will not take much power on AM, maybe 100 watts.
    They can heat up and melt the pvc forms they are wound on.

    So its a lower power antenna. I am not sure how 6 meters will work, I have never seem 6 included on a fan dipole.

    I know everyone will say OWL and a good tuna, but it would be a real problem to get the owl into the shack through tree's and gutters and brick, and into the shack where there is no balanced tuna.

    Fan dipoles take some careful pruning but once done are fantastic to use.
     
  2. K5UJ

    K5UJ Ham Member QRZ Page

    What's LB stand for? Maybe you can replace the coil forms with ceramic or copper tubing air coil bolted on ceramic insulator for strain relief and run more power.
     
  3. K4KYV

    K4KYV Premium Subscriber Volunteer Moderator QRZ Page

    I would vote "yes" for a proposal to for ever ban acronyms from the internet. :mad:
     
    W2VW likes this.
  4. K2XT

    K2XT Premium Subscriber QRZ Page

    Looks like it is the model of the Alpha Delta antenna he intends to buy. It appears to be a coil loaded dipole.
    He didn't have a specific question. Just said he was going to buy the commercial antenna and add fan dipole elements to it.
    <<<<< So it looks like we can all join Rudy St. Bernard here and go back to sleep.
     
  5. K5UJ

    K5UJ Ham Member QRZ Page

    Well, if he can improve the coils he can run more power, which is always good if you ask me.
     
  6. N2DTS

    N2DTS Ham Member QRZ Page

    LB stands for Low Band I suppose.
    I had one before, the LB plus which had the fans added, a 160 to 10 meter antenna.
    I do not plan on running high power into this junk on 160 or 80 meters.
    The system works by making the coils close spaced so they sort of work like a trap, but without a capacitor to fail.
    The enameled wire is 18 or 20 gauge about, good for about 150 watts of AM I guess, I would run it under 100.
    I have been having fun running lower powers lately.

    Timtron once told me if you run high power, weak people call you and you have to fight to hear them.
    Run low power and strong people call you and THEY have to fight the noise!

    If I want to run 600 watts carrier from the 813 rig on 80 or 40 meters, I have the other fan dipole without power limitations.

    I already have the LB antenna, and made the new legs for 20, 10 and 6 meters.
    I have some coax work to do, and I need to make the spreaders.
    I use fiberglass rods they sell to hold markers for snow, about pencil thin, drill a small hole and pass a thin wire through to hold to the antenna sections.

    Two really nice things about a fan dipole, no switching between bands, and if you get it set right, no tuna needed or to tune.
     
  7. KF7TLL

    KF7TLL Ham Member QRZ Page

    If you plan on running the DX-LB on 160 with any kind of power take out the Lightning slug.. it will not handle anything more than 100w with it in it and that's on SSB... I had the same antenna that I used mostly on 75m even AM with 150-200w carrier with no issues, But 160m is a isuue....... you can GOOGLE that antenna and find the same conclusions...

    TAKE OUT THE LIGHTNING SLUG FOR 160M USE !
     
    N6YW likes this.
  8. N2DTS

    N2DTS Ham Member QRZ Page

    [​IMG]

    Made the antenna, used different color wire for each band, 160 to 6 meters.
    It will need to be trimmed and tightened up some.

    This antenna did not come with the center spark gap or whatever it is.

    I had to order some dacron rope as the stuff in the tree in front is stuck, the tree grew around it I suppose.
    [​IMG]

    I used copper wire through the holes drilled in the fiberglass rod to hold the legs.
    This has been working ok on my other fan dipole.
    Plastic spreaders and plastic wire ties degraded badly and quickly when I made open wire line out of those.
    I cut a foot off the center of the Alpha Delta antenna to move it into the phone section of the bands.
     
  9. KA4KOE

    KA4KOE Ham Member QRZ Page

    Multiple wires under one nut?
     
  10. KA4KOE

    KA4KOE Ham Member QRZ Page

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