What kind of antenna would be used for 2-meters SSB mobile operation?

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by KC0BUS, May 28, 2019.

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  1. W4OP

    W4OP Ham Member QRZ Page

    Getting back to the original subject ,there IS a difference between the Omniangle (isosceles triangle) and the round or square "halos". The Omniangles are an entirely different design. They are electrically longer than the halos and it is the shape and electrical length that yields a pattern that has a far better omni pattern than halos/squalos. In addition, the halos all seem to suffer from mast radiation and common mode from the coax. The Omniangles suffer from neither.
    Anechoic plots may be seen at:
    http://www.parelectronics.com/omnis.php
    Click on the blue hypertext:

    http://www.parelectronics.com/omni-patterns.html
    Dale W4OP
     
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I must admit, for VHF "roving" I've tried round loops (halos) and square loops (M2) and also the Ominiangle, and the Omniangle did seem to work better.

    Difference may only be 1-2 dB, but when you're looking for weak signals in the noise, that helps.
     
  3. KF5FEI

    KF5FEI Ham Member QRZ Page

    Are they still making the omniangle antennas?

    Universal Radio was the only reseller I've found, and they list all models as discontinued. Par Electronics has a small link at the bottom of the omniangle pages to email for pricing. Guess you'd have to drop them a line if you want one.
     
  4. KC3BKG

    KC3BKG Ham Member QRZ Page

    I have ordered several direct from PAR. Just send them an email with what you want and shipping zip. I have had great customer service from Dale. I have 2 OA-144 stacked and a lone OA-50. I consider them very well made, simple to assemble and have very good SWR around the tuned frequency. Have never tried mounting one on a vehicle though...:cool:
     
  5. K3RW

    K3RW Ham Member QRZ Page

    Dale will probably not give up the trade secret--but how are the omniangles matched? There's a mysterious black box on my 432 one with the N-connector, and that's all I know. I figure its a balun of some sort, but not sure what characteristic impedance these omniangle loops have, since they aren't 'folded dipoles', etc. And since it matches to 50ohms, I don't know if it was 200 ohms, 25ohms, etc. They aren't just a folded loop, its electrically longer than that. So it has some difference there and it seems to be a good one.

    FWIW, it is an excellent setup. I had the M2 omnis before on 6, 2, 432, and these are far better. Decent sharpness on 432. Had to borrow an Anritsu to 'tune' the 432 ones, and it was tricky. But its not 'all flat across the band' that people mistakingly think is a good thing! :D
     
  6. K3RW

    K3RW Ham Member QRZ Page

    My original answer was to say--use a omniangle loop. And if its not a really tall truck, consider stacking them. I couldn't do that on top of my SUV, but I could do it on my much lower Subaru.

    I will get laughed at, but for 2m SSB operations I would even give consideration to a small, short boom yagi. Not a 10el type, maybe more like a 3-4 element type like my Arrow, fixed high above the roof of the car. My thinking here is that I-5 runs mainly N/S and most people live within 20mi of it here in the Pacific NW. There's no reason to run a long boom yagi with a super tight beamwidth. And the terrain with coastal range mountains on one side and the Cascades on the other, there's very few operators on 2m SSB outside from the major population centers--speaking strictly for OR/WA/BC off I-5. Same is likely true for I-90. Eastern WA and OR is basically a VHF deadzone for contesting.

    With a shorter boom and not super tight element spacing, the radiation pattern blobs out a decent amount, which would give of course less forward gain, but perhaps a bit better for SSB/mobile. No reason to run strictly an omniangle when you'd potentially want a little gain forward of your path of travel, rather than a perfect omni which is picking up sides and backs just as well as fronts, but as you're moving away from an area--that's probably less desirable. And a beam like my Arrow isn't a radiation pattern like a laser beam.

    So that gives me a bit of forward gain vs an omni, and still has some side lobes but not as much as an omni. And its still very workable off the back end. At least my thinking is if you're driving away from Portland headed north, why would you not want a bit of directionality to the north, for example.

    I recall one op suggested to me to use an omni low above the roof of the car for working satellites--claimed it works as a reflector. Haven't tried that yet.
     
  7. W1VT

    W1VT Ham Member QRZ Page

    When I had a Saturn sedan I put a roof rack on it that I used as a mounting platform for a 12V rotator and stack of Yagis to cover 144 to 432MHz and and H frame to cover 903, 1296, 2304, and 3456 MHz. I have a half width rack for my 903 to 3456 MHz transverters.
     
  8. KF5FEI

    KF5FEI Ham Member QRZ Page

    I've had good luck working the FM sats with the generic (cheap) 2m / 70cm 1/4 wave NMO-mount antenna mounted in the middle of the roof. Only drawback is not knowing your grid-square while you are blasting down the freeway at 70+.
     
    K3RW likes this.
  9. AF7XT

    AF7XT Ham Member QRZ Page

    [​IMG]
    courtesy of KC3RE
     
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