Do dipoles require baluns?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by K9PSM, Jan 25, 2010.

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  1. G3TXQ

    G3TXQ Ham Member QRZ Page

    I would never bother installing a balun on a dipole to preserve its "pattern"; but I do install them as a precaution against "RF in the shack" problems and noise pick-up.

    I really don't understand how those pioneers after World War II managed without a balun. How on earth did they prevent interference to and from their cordless 'phones, their TVs, their computers, and the digital ICs in their ham equipment ;)

    Steve G3TXQ
     
    MM0HVU likes this.
  2. KL7AJ

    KL7AJ XML Subscriber QRZ Page

    Dipoles don't REQUIRE baluns, but they should have them for predictable results. Unless you're using a totally balanced system to start with.

    Back before I knew anything, I used a 40 meter dipole without a balun. I also used it on 80....and probably the only reason I got by with that was because I DIDN'T have a balun....my coax was probably doing most of the radiating. I worked the world for a couple of years this way....clueless but blissful. :)

    eric
     
    MM0HVU likes this.
  3. KD0CAC

    KD0CAC Ham Member QRZ Page

    eric ,
    Noticed you do not cap.
    Could you give some theory / application on that ?
    I am still finding like many of the other aspects of each subject or component , it can open up a vast spectrum of issues .
    Thanks John
     
  4. W5DXP

    W5DXP Ham Member QRZ Page

    In my RF Engineering classes, I learned that it is good engineering practice to install a balun at every BALanced to UNbalanced point in the RF antenna system. I doubt that one can find a professionally designed RF antenna system that violates that rule. Amateur designed RF antenna systems are another matter altogether. :)

    I had no idea what a balun was when I put up my first coax-fed dipole in 1953 and wound up with an RF burn on my lip from RF-in-the-shack.
     
  5. K9PSM

    K9PSM Ham Member QRZ Page

    Glen,

    My 10 meter dipole has a balun that was provided. Since I now know that I do not need one, when I go to upgrade my license and build the 40, it will have no balun.

    Also, where can I find the lowest prices on antenna switches?

    Paul,
     
  6. G3TXQ

    G3TXQ Ham Member QRZ Page

    Paul,

    Just curious why you've chosen to ignore so much advice:

    Your choice, of course; but I hope you don't have to learn the hard way as others have done!

    73,
    Steve G3TXQ
     
  7. W5DXP

    W5DXP Ham Member QRZ Page

    Maybe it was tongue-in-cheek humor???
     
  8. K9PSM

    K9PSM Ham Member QRZ Page

    Steve,

    I'm sorry, I guess I wasn't reading this right. What is an easy way to create a balun for a dipole?

    Paul,
     
    W9GOS likes this.
  9. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    QYB:

    Unfortunately, "low price" and "coaxial switch" are basically mutually excepting terms. Well, a better explanation is that a "low priced" coaxial switch is generally going to cause a lot of problems.

    Glen, K9STH
     
  10. W4PG

    W4PG Super Moderator Lifetime Member 279 Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    You asked do you *have* to have a balun. By now, you should realize that you don't HAVE to have one, but you probably DO want one. There are SO many more devices in the ham shack today susceptible to RF that a good ham wants to do ALL he/she can to prevent RF in the shack.

    Baluns for dipoles are cheap, usually a few dollars, and are WELL worth it. Most any major ham radio distributor will have them, as well as coax switches.

    I had to chuckle at the post about the lip burn! If you've ever had too much RF in the shack and got the mike to close to your lip, well . . . trust me.

    You'll be out buying a balun the next morning!! :D

    ........Bob
     
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