Would modifying my vertical mobile antenna to work horizontal as well, work?

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by KC0BUS, May 29, 2019.

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  1. KC0BUS

    KC0BUS Ham Member QRZ Page

    I have a base-loaded 5/8-wave 2-meter mobile vertical antenna whip that is also supposedly resonant on 6-meters as well, only on that band at 1/4 wave. It's an NMO base-loaded magnetic mount mobile antenna intended for regular FM work on 2-meters and it does this job very well indeed. I got to thinking about possibly putting a 90-degree bend in the whip element about half-way up the length of the steel whip. This would (in theory anyway) allow me to use this same antenna also on 6-meters (as well as 2-meters too I suppose) Single Side Band (SSB) too, would it not, since all SSB work is done horizontally polarized?! If not, why not?
    Thank you
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    It would probably help a bit, but remember as soon as you do that, you have a directional horizontally polarized antenna which will work in two directions, broadside to the horizontal element.

    Might be fine if you're parked and can aim the car to favor whoever you want to work, but if you're in motion, I can see this as a big handicap.
  3. ZL1TKL

    ZL1TKL Ham Member QRZ Page

    6 meters divided 4 =1.5
    2 meters divided 8 =0.25 x5 = 1.25
    sorry theory wrong
  4. KC0BUS

    KC0BUS Ham Member QRZ Page

    If it became 'directional', even just somewhat, which direction would it favor exactly in relation to the elements?
  5. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    The broadsides of the horizontal part of the whip, with two nulls in the directions 90 degrees offset to that.
  6. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Actually, in terms of impedance matching, it works perfectly.

    The 5/8-wave 2m whip uses a series inductor inside the NMO base housing to cancel the capacitive reactance of a 5/8-wave antenna and resonate it on 2m. That series inductance acts as a loading coil on 6m, so although the whip is physically too short to be a 1/4-WL on 6m, it is electrically a 1/4-wave and does resonate on 6m.

    Hams have been successfully using that effect for decades.
  7. K8JD

    K8JD Ham Member QRZ Page

    Thoughts on Six Meter Mobile
    On FM , a vertical 6M mobile antenna is best for local work. When the band is open It makes no diff.
    SSB local would be better with a horizontal like a Halo or SQUALO type, Again when the band opens it makes no diff, horiz or vert polarization !
    What DOES matter is the FM is on the higher end of the band and SSB is on the lower end. 50 Vs 53 MHz ! You gotta have two antennas or choose your mode !
  8. WA3VJB

    WA3VJB Ham Member QRZ Page

    Scott Fike KC0BUS, has asked more than 1,000 questions on here the past 15 years. Most are open-ended, vague like this one, and he rarely shows any sign of making use of the information. One thread he initiated appeared to be a topic he could be planning to write a book about. Thus, with all the responses he's got to all his questions, we could be helping write such a book for him, the theory goes !!!
  9. K8JD

    K8JD Ham Member QRZ Page

    I see a lot of vague posts and a hundred answers but the original poster never comes back :eek:

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