I have been reading the Basic Antennas and

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KD9DOG, Jun 26, 2021.

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  1. KD9DOG

    KD9DOG Ham Member QRZ Page

    Can I put up a wire that I do not need a tuner say 40 meters for a starting point I am just trying to save a few bucks by eliminating the tuner.
     
    KO4ESA likes this.
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Center-fed 1/2-wavelength dipole, 65' long end-to-end, up 30' or higher above ground and fed with 50 Ohm coax can cover the 40 meter band without using a tuner.
     
    WB5YUZ, KO4ESA and K0UO like this.
  3. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

    Although the above advice and you'll be just fine.
    I never used a tuner for 40 years
     
    KO4ESA likes this.
  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I can tune an antenna, but how do you tuna fish?:)
     
    KO4ESA likes this.
  5. KD9DOG

    KD9DOG Ham Member QRZ Page

    I myself will not touch that!!!
    Thank you, now what do you do with the coax as I intend to hang this from my flag pole to a pipe 115' away strapped to the fence and being center fed the coax would drop into the mowed section of the yard?
     
    Last edited: Jun 26, 2021
  6. N3PM

    N3PM Ham Member QRZ Page

    I've always mowed the lawn, placed the coax and let the stuff grow over it.
    Mike N3PM
     
    K2EDM likes this.
  7. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    As long as the coax runs at a 90 degree angle (or close to that) to the dipole wire, it can run anywhere -- doesn't have to be straight down.

    I often pull the coax back towards the roof of the house and support it with an eyehook (or something) near the edge of the roof, so all the coax is at least as high as the roof is, assuming the dipole is actually higher than that.

    Many ways to deal with this issue; hams have been dealing with it for 100 years.
     
    KX4OM likes this.
  8. WA9FZB

    WA9FZB XML Subscriber QRZ Page

    Don't forget the "Easter Egg" hidden in that 40 meter dipole . . . you can also load it on 15 meters! Usually no tuner needed there, either.
     
  9. W7PDK

    W7PDK Premium Subscriber QRZ Page

    If you have room, a horizontal loop will give you multiple bands and good performance.
     
  10. K6GBW

    K6GBW Ham Member QRZ Page

    I've tried just about every type of wire antenna there is and I keep coming back to the regular old dipole. It's just really hard to beat it as a general purpose antenna. Build it a touch long and then trim it down to the middle of the portion of the band you use and you're golden.
     
    K9UR, WD4DXQ and K2EDM like this.
  11. W1VT

    W1VT Ham Member QRZ Page

    If you have the room I've been using a full wave dipole fed with a quarter wave 500 ohm matching section. The spacing of the matching section can be adjusted to compensate for the fact that the antenna impedance varies with the height above ground.
    Antenna modeling can be used to accurately "pre-tune" the antenna.

    Zak W1VT
     
  12. WA7ARK

    WA7ARK Ham Member QRZ Page

    Nope. I just measured one yesterday as part of a Field Day set-up. A 66.3ft dipole at 35ft agl resonates at 7.15MHz where its Swr50 is about 1.4. Its third harmonic resonance is at 22.11MHz (too high). Its Swr at 21.2 MHz is over 3.5, and would need a capable add-on tuner. Even the whimpy built-in tuner inside my Icom 7300 would have trouble with it....
     
    KI4ZUQ and WB5YUZ like this.
  13. WB5YUZ

    WB5YUZ Ham Member QRZ Page

    People are now going to come forward, each with their own favorite antenna type, often blindly ignoring the OPs preference for a "starting point" antenna that will work well without a tuner.

    I believe OP can do no better than to start with a simple dipole. I think there will even be a consensus on this one, although, again, there will also be endless suggestions of pet antennas, as well.
     
  14. KD9DOG

    KD9DOG Ham Member QRZ Page

    Here is where I am at, after numerous searches for a multiband antenna it came to the Butternut Ant. After installing this Butternut and laying down some 30 radials it does not want to stay in tune. Like there is only so much room on this pole and following the directions as soon as the wind picks up everything is out the window. Then it starts over again me going out with the analyzer and adjust it. I am giving up on this thing and going with Dipoles, I have two more question; How much distance do I need between antennas say a 40m and 80m I am going to figure out the bands I want to work and build a dipole for each one also can I support these antennas from a single point (flagpole) and fan out from there?
     
  15. WA7ARK

    WA7ARK Ham Member QRZ Page

    If co-locating two different band center-fed dipoles, if you separate them by even a few inches, you can use one coax feedline. If the dipoles run off the mast at two sets of angles (for example, looking down, bird's-eye view, one running N-S the other running E-W) then there is zero potential interaction between the two bands, even if the included angle between the two dipoles is as little as 10 degrees.

    This is called a "fan dipole". To minimize interaction between the two bands, you should put a "1:1 balun" (aka coax-choke or line-isolator) between the coax and the dipole wires. Think of the "line isolator" as being the center insulator for a dipole.
     

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