Off Center Fed Dipole vs Fan Dipole

Discussion in 'Ham Radio Discussions' started by W9EMM, Jan 30, 2021.

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  1. W9EMM

    W9EMM XML Subscriber QRZ Page

    Here is a question for you Elmers, I don't have one so I will ask here. If you were going to use a OCF or a Fan Dipole witch one would you choose and why?
    I am now using a OCF dipole works well, but if a Fan dipole is better it would be a good project when the weather permits. The fan dipole I had is mind is what some call a fence dipole the elements are spaced vertically spaced apart at the center if you know what I mean.
    To get back to my question will I be better off with a fan dipole?
    Jim W9EMM
  2. WT4W

    WT4W XML Subscriber QRZ Page

    You're gonna' get a mess load of opinions as to which is 'better', and a lot of it depends on your expectations. I'll just say that I'd chose a fan dipole because of the convenience of having multiple bands available without having to use a tuner.
    WA9SVD and VK6APZ like this.
  3. AI3V

    AI3V Ham Member QRZ Page

    Without a doubt the CENTER FED SYMETRICAL fan dipole.

    Any "off center fed" is just a pair of random wires, on the end of a random transmission line, with more or less random coupling thru the rig back into the house wiring.

    Hertz used symetrical antennas to prove Maxwell's theory, you should too.

    KA4DPO, WA5VGO, WA9SVD and 2 others like this.
  4. K1VSK

    K1VSK Ham Member QRZ Page

    To state the obvious, whichever one you can get the highest. If that’s not a consideration, the fan dipole is usually a more effective antenna.
    WA9SVD and KB0QIP like this.
  5. WA9PND

    WA9PND XML Subscriber QRZ Page

    Hardly. My OCFD works fine on 40m/ 20m/ 15m/ 10m/ 6m without a tuner. Hard to do all those bands with a fan dipole.
    KV5J and KB0QIP like this.
  6. N2DTS

    N2DTS Ham Member QRZ Page

    I like fan dipoles.
    I make them out of solid #12 insulated wire for the longest element and hang #16 solid below using tubing with holes drilled in it to pass the wires through, and tie them in place with pieces of the #16.
    I have 80, 40 and 20 but used to have one that had 6 meters as well.
    No tuner, no balun, no traps or active components.
    I have it tuned for a 1.2 to 1 swr where I operate on every band, no RF in the shack, no loss on the coax or in a tuner or balun.

    Stranded wire gets tangled up and is not STIFF.
    Thicker wire is stronger and more broad banded, a full size antenna tends to be broad banded.

    I love being able to jump from band to band and not needing to tune or select anything...

    Alpha Delta makes a fan dipole that covers 160 to 10 meters.
    160 and 80 use coils that shorten and separate sections and they:
    Do not take much power,
    Do not hold up to the WX,
    Make the bandwidth narrow.

    But it does work, 110 feet long.
    40 and up are full size antenna's.
    15 meters uses 40 and is wonky...
    KB0QIP likes this.
  7. KB0QIP

    KB0QIP Ham Member QRZ Page

    I'm putting a new shack up and will be putting up a OCF dipole. HOWEVER, I will also have a Fan dipole going up also when completed. I really enjoy building the Fan dipole and once tuned it works well.
  8. W5IEI

    W5IEI Platinum Subscriber Platinum Subscriber QRZ Page

    I have both.
    A fan for 160/75,and an Array solutions 80-6 5KW OCF.
    I prefer the fan ,but the OCF works ok,not nearly as well as the fan though.
    KU3X and N1VAU like this.
  9. K8BZ

    K8BZ Ham Member QRZ Page

    There is a reason many ham bands are harmonically related. A center fed 1/2 wave dipole will be usable on the fundamental frequency and on odd harmonics. Therefore, an 80 meter dipole will be usable on 80, 30, 17, 12 and 6 meters with some gentle tuning that should be manageable with an internal tuner. Add a 40 meter dipole to the feed line and you get 40 and 15 meters. Most fan dipoles I see use 40 meters as the lowest band. You miss out on the odd harmonic advantage of 80 meters and have to add a lot more 'blades' to the fan to get as many bands.

    Someone needing to get the most bang for the buck and efficiency of available antenna space would get a lot of usable bands with an 80/40 fan dipole. Add 20 meters and you have HF covered.

    If you need/want to use as much of each band as possible because you like to work CW/digital end of the band and SSB portion, I would suggest the fan dipole for 80 and 40 over an OCF, but that's just me. And that's just considering the OCF and fan dipole as the only options. Add a ZS6BKW to the list of options and I would go with the ZS6BKW over either of the other options.
    Last edited: Jan 30, 2021
  10. KU3X

    KU3X Ham Member QRZ Page

    Both are good antennas if built properly. The big advantage of a fan dipole is you can trim each antenna for your desired frequency. With an OCF, you
    are kind of locked into what you get. Usually an OCF80 is resonant near the bottom of the band. By trimming it so it's resonant close to the top of
    the band, all of the other bands now get out of wack.
    The big advantage of an OCF is, two wires, one coax and numerous bands. I use one when I set up portable. I would not want to set up a 6 band fan dipole when I operate portable.

    Tied for first choice would be a fan dipole or an 80 meter center fed dipole fed with parallel feeders. The OCF80 would be my second choice.

    Last edited: Jan 30, 2021

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