Dipole Antenna

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KI4QHM, Aug 1, 2020.

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  1. KI4QHM

    KI4QHM Ham Member QRZ Page

    Hello,
    New General Ham here. What is the recommended antenna height for a dipole antenna? Not hearing much at all on SSB. Only hear CW, FT8, PSK31. The best I can do is about 5ft off the ground unfortunately. Thanks for your help.
     
  2. K6CLS

    K6CLS Ham Member QRZ Page

    Ouch, no dipole for any band will do much at that low height. The usual recommendation for height is at least 1/4 wavelength high, for whatever band you're on. So, 5 meters for a 20m dipole. Higher is better.

    Ok if you can only raise the center. The ends can droop a bit, not tooo great an angle.

    Can you raise the center a bir? Do you have a painter's pole or a long closet pole?

    If all you can do it 5 feet, get a magloop.
     
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  3. AJ5J

    AJ5J Ham Member QRZ Page

    One-half wave-length above ground is always recommended as a general minimum height for chasing dx; higher than that is often better.

    Five feet is seriously low for any band, hence your dismal results thus far. What band(s) do you wish to work?

    73, Jeff
     
    K0UO likes this.
  4. KI4QHM

    KI4QHM Ham Member QRZ Page

    Thanks guys for the help. The area I live in is HOA and trying the best to hide a 140ft dipole is very difficult. Just wanted to know. Going to see my other options are, maybe a vertical?
     
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  5. AJ5J

    AJ5J Ham Member QRZ Page

    Yes, if you have a tall tree (or any tree, for that matter) you may succeed in hiding at least a good portion of a vertical antenna. A small transmitting loop (STL) is also another type of vertical that can work very well only inches above ground---but building a proper one takes a bit of patience to get things right (I can guide you further if interested). FWIW, the first station I worked on 17 or 20m (don't remember which now) was in Utah (I'm in South Texas). The second station I worked was in Barcelona and the third was in Sicily.

    STLs "spray" RF at both low and high angles and everything in between---making them great for local, regional and dx operation and in restricted spaces. I also live in a HOA condo and they're easily set up and taken back inside when QRV/QRT.

    For starters, though, a simple wire up into the tree(s) with many (or a few if elevated) radials will do you well for getting on the air sooner than later. I'd suggest a 16.5-foot length wire and radials for 20 meters which is reliably the best place for 20m dx generally speaking.

    73,

    Jeff
     
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  6. KI4QHM

    KI4QHM Ham Member QRZ Page

    Thank you so much Jeff. I hate coming on QRZ to ask questions. Makes me feel silly. I greatly appreciate your help. Going to do some research tonight. Thank you so much.
     
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  7. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    First, I'd recommend skipping the "140' dipole" as that implies you want to use it on 80 meters; with a low dipole and 100W on 80m (or especially on 75m SSB), almost no one would hear you.

    I'd focus on the higher frequency bands where antennas are smaller, or at least "shorter." A 40m dipole is only about 65' long and certainly easier to install than a 140' one. But any kind of horizontal dipole for HF will not do much at five feet above ground.

    If you can hide or get approval for a vertical, probably a much better choice. If not, a lot of HOA folks have good success with STLs (small transmitting loops) which can work when they're very low, especially outdoors like on patio or something. STLs are very special antennas that are sharply tuned and narrow band in response, but if you can tune it, a single STL might cover 3-4 ham bands. They can be homebrewed, but there are a few good ones on the commercial market, including some that have "remote" tuning so you can be inside by the radio and tune the antenna that's outside on a patio, deck or whatever. Small enough to be brought indoors when not in use.
     
  8. KI4QHM

    KI4QHM Ham Member QRZ Page

    I only need something for 40 and below. Going to look at some ideas. Thank you for the help.
     
  9. AJ5J

    AJ5J Ham Member QRZ Page

    You're welcome. I researched STLs via Yahoo groups (of old, now groups.io I think) and all around the deepest internet seas for a year or two before I actually set about to building one. I have several now at the ready and am actually planning to try my hand at larger ones for 80 and 160 once we get settled into our new house down the street. One can never have too many antennas!

    I suggest reading this for starters:http://www.ahars.com.au/uploads/1/3/9/8/13982788/article-antenna-mag-loop-2.pdf or at least skimming through it and see if it grabs you like it did me.

    Search VK4AMZ and VK5SFA too; they have built some amazing ones.

    Another good stealth but effective HOA antenna for 10-80 meters is a good screwdriver (Ron, NI7J, builds the best---Scorpion---but Tarheels are also decent). Add a taller radiator and a cap hat, install radials and work the world---remote tunability is an added bonus---no tuner required.

    Got to go now but the above should keep you busy. Researching antennas is almost as much fun as actually building and using them!

    73,

    Jeff

    EDIT: Posted the above before I saw your 40m and down need---that's perfect for a screwdriver, especially if you fabricate a 4-10-foot tall copper pipe "whip" and DIY a big cap hat for the top. If you could elevate it just a few feet above the ground you could easily do well with only 2 radials per band of operation, too. Details tomorrow....
     
  10. K2CAJ

    K2CAJ XML Subscriber QRZ Page

    It looks like you got some good trees just at the SE corner of your property. You can probably conceal a vertical quite well there, and it would also be maximally far from the houses.
     
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