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Thread: 3-element beam / Yagi for 10 meters: What can I expect?

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  1. #1

    Default 3-element beam / Yagi for 10 meters: What can I expect?

    I was just given a 3 element beam antenna. Some simple estimated measurements (~16+ ft elements) lead me to believe it is a 10 meter antenna. It does not have any traps or coils.

    It has a gamma match but I might have to work with/repair that. Is there a good source of information on gamma match specs for a 10 meter 3 element beam? If there is, I can make sure I'm in the ballpark. I take it that if you don't use one, you'd have to settle with the impedance mismatch or you'd have to trim the antenna, right?

    If any of you have used a 10 meter, 3 element beam before, what were your results? Have you used one recently when the band was open? What type of gain can be expected, 7 or 8db over a dipole?

    I have a G5RV, which is not a great antenna for 10 meters, but I have made some fun DX contacts. I also have a vertical CB antenna that I messed around with on 10 meters and had fun talking to Asian stations.

    I'm just experimenting right now and everything is temporary. My G5RV is in an inverted V configuration right now with the apex at a measly 25ft. The small vertical is at 6ft above ground. The best I could do right now with the 3 element beam would be about 20ft above ground.

    If I get this 10 meter 3 element beam working right, what difference if any could I expect over the G5RV or the small vertical?
    Rigs: HW-8, HW-100, Swan 600 Twin, Kenwood TS-570d(g)
    Keys: Bencher BY-1, Heathkit HD-1410, J-38
    Dipoles: 160-30m inverted V, Buckmaster OCF
    Beams: Homebrew 6-band Spiderbeam (30-10m), K4KIO Hexbeam (20-6m)
    Verticals: ZeroFive 43-foot Vertical

  2. #2

    Default

    Rigs: HW-8, HW-100, Swan 600 Twin, Kenwood TS-570d(g)
    Keys: Bencher BY-1, Heathkit HD-1410, J-38
    Dipoles: 160-30m inverted V, Buckmaster OCF
    Beams: Homebrew 6-band Spiderbeam (30-10m), K4KIO Hexbeam (20-6m)
    Verticals: ZeroFive 43-foot Vertical

  3. #3

    Default

    I was just given a 3 element beam antenna.
    Some simple estimated measurements (~16+ ft elements) lead me to believe it is a 10 meter antenna.
    It does not have any traps or coils.
    Yes, this sounds like a MONO-Band, 10-meter yagi. Get a tape measure and measure the boom's length and tubing OD.
    IF you could attach some photos of this antenna's feedpoint or boom/element attachments --
    then we may be able to idenitfy the manufacturer for you.

    There were also some 11/10-meter 3-element beams made in 1960s/1970s (such as the Maco 103C, 11.5 feet boom length) --
    http://www.macoantennas.net/AntennaD...ages/M103.html

    You adjusted the polarization, element length and/or matching system for optimal usage (desired operating frequency)
    as outlined in the M103C manual.
    http://www.macoantennas.net/files/M103C_2011.pdf

    w9gb
    Last edited by W9GB; 10-16-2011 at 03:36 PM.
    Nullius in verba

  4. #4

    Default

    I was just given a 3 element beam antenna.
    Some simple estimated measurements (~16+ ft elements) lead me to believe it is a 10 meter antenna.
    It does not have any traps or coils.
    The Cushcraft 10-3CD Skywalker is their 10-meter, 3-element (mono-band) beam
    http://www.cushcraftamateur.com/pdffiles/951349.pdf

    If I get this 10 meter 3 element beam working right, what difference if any could I expect over the G5RV or the small vertical?
    IF you enjoy the DX hunts on 10 meters, when the solar conditions are good,
    you should be pleased with the directional performance -- compared to an omni-directional vertical.

    w9gb
    Last edited by W9GB; 10-16-2011 at 03:35 PM.
    Nullius in verba

  5. #5

    Default

    Performance will be poor to excellent depending on how carefully it is assembled/tuned, height mounted, topography, and propagation. Considerable ground gain is possible which ads to the basic yagi gain.

    Carl

  6. #6
    Join Date
    Jan 2000
    Location
    Kilowatt Alley
    Posts
    9,864

    Default

    what difference if any could I expect over the G5RV or the small vertical?
    If set up right at a decent height, It is like the difference between driving an old Datsun B210 and a new Camaro.

    It would be a huge improvement on 10 meters.
    Much better signal strengths.
    You don't notice the QSB nearly as much due to higher signal strengths.
    Much better signal from you to the DX.
    Can carry on a QSO far longer.
    It's directive.
    Less noise when horizontal.
    ...looks cooler!
    There is really no comparison.
    "Oh what a tangled web we weave when first we practice to receive."
    -Otto Watt Sept. 5 1925

  7. #7

    Default

    When inspecting / reassembling / etc., what do I need to do at the joint sections (cleaning, etc)? I'll post pics later today...
    Rigs: HW-8, HW-100, Swan 600 Twin, Kenwood TS-570d(g)
    Keys: Bencher BY-1, Heathkit HD-1410, J-38
    Dipoles: 160-30m inverted V, Buckmaster OCF
    Beams: Homebrew 6-band Spiderbeam (30-10m), K4KIO Hexbeam (20-6m)
    Verticals: ZeroFive 43-foot Vertical

  8. #8

    Default

    I always sand the element part that slides into a bigger section and use a wire brush for its inside. Then lightly coat with electricians aluminum wire antioxidant. Use all stainless hose clamps, not ones with regular steel wormscrews.

    Carl

  9. #9
    Join Date
    Jan 2000
    Location
    Commerce MI (Detroit area)
    Posts
    8,083

    Default

    I bought my HyGain 103 10M Yagi when I bought my brand new TS520 so that dates it.
    I had to replace the rusty hose clamps the elements were assembled with when I moved to this QTH, 22 years ago, I did the steel wool cleaning when I put it back together .
    I had been using an 8 ft GP vertical at 20 ft and the new Yagi was night and day difference. I rarely got into Europe or Asia with the GP and the Yagi got me DX like I could not believe !
    I wkd islands in the Pacific that I had to go over my old National Geographics maps for hours to find !

    Quote Originally Posted by KM1H View Post
    I always sand the element part that slides into a bigger section and use a wire brush for its inside. Then lightly coat with electricians aluminum wire antioxidant. Use all stainless hose clamps, not ones with regular steel wormscrews.

    Carl
    73.....JD, FISTS #3853,cc 455,SKCC # 1395,tribune #12,
    Official US Taxpayer

  10. #10

    Default

    NoAlOx or similar is a good anti-oxidant. I use "ScotchBrite" polishing cloths to buff up the aluminum interfaces, then apply NoAlOx, which can be found at many hardware stores and virtually all electrical supply houses. It's cheap. ScotchBrite cloths are in most grocery stores and lots of places.

    Don't use steel wool.

    A gamma match is essential for designs where the center of the driven element is grounded to the boom, and that's the reason beams use gamma matches. If the element is insulated, you can use other stuff. Hy-Gain doesn't use a gamma, they use a "beta" match with an insulated driven element.

    They both work.

    The gamma tunes out element reactance but it won't change radiation resistance, so the element has to be the right length to begin with. 16' elements indeed sounds like a 10m monobander.

    Compared to a G5RV on 10m (and a G5RV is truly a terrible antenna on 10m), this will be like going from a stepladder to a crane. You're going to be very surprised how much better it is.
    What if soy milk is just regular milk introducing itself in Spanish?

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