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7/8 wave 2 meter mobile

Discussion in 'Amateur Radio Antennas' started by towerdog, Jan 8, 2010.

  1. towerdog

    towerdog one-niner-seven

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    who makes it and what is it, a 7/8 wave antenna for 2m (and 440?) I suspect its a 5/8 wave over 1/4 wave. I have been told this would be a better mobile antenna than a 5/8.


     
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  2. bob85

    bob85 Supporting Member

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    towerdog, if you mean the 7/8wave shuntfed whips that look like an old smc oscar foldover cb antenna i cant remember who made them, i have seen them with different brandnames on the same antenna,
    they are a 7/8wave single element antenna,
    i tried a ham buddies 7/8wave that he raved about against my identical looking but shorter 5/8wave and got more flutter on my mobile signal with the 7/8wave:thumbdown:,

    if you mean a 5/8wave over 1/4wave colinear thats a different ballgame, the radiation angle can be manipulated by the designer to give a lower or higher radiation angle and higher gain than a single element antenna at the expense of vertical beamwidth, the result may or may not suite your mobile needs :)
     
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  3. Wire Weasel

    Wire Weasel Senior Moment

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    Not sure about 7/8 but Hustler makes what I believe is a colinear 5/8 (two 5/8's put together one of top of the other) Any Hustler dealer should have them. Ham Radio Outlet sells them.

    The 3/8 x 24 threaded is model # CG-144

    Trunk Lid Mount is # CGT-144

    I've used one in the past. Work well. Best if you can locate in the free and clear.

    Good luck
     
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  4. IMD262

    IMD262 Well-Known Member

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  5. towerdog

    towerdog one-niner-seven

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    thats it! what I was looking for, thanks. I beleve flutter can be caused by the whip whipping around too much in the wind, I heard you might have radiation pattern issues from insufficient ground plane from a 7/8 also but I will read up on it, and check the reviews out.

    thats model, CG-144 is a 5/8 over a 1/4. I cant find a colinear for mobile but did find this stacked 5/8 colinear for base application. Base Model G7-144 with 7dB gain. If that 7dB is true, thats more than some directional antenna, pretty cool, I might try to build such a thing. Is co-linear the same as co-phased?
     
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  6. SR385

    SR385 Active Member

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    Keep in mind, the more gain, the 'flatter' the radiation pattern gets....it gets narrow as a razor. On flat, open ground or slight elevation advantage, this can be great. In varied terrain with rolling hills and buildings, this can actually hurt you vs a much higher angle of radiation on a no or low gain antenna.
     
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  7. CDX-007

    CDX-007 Transducer Fanatic

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    I and two friends both tried the Hustler 144 and never got performance as good as the base loaded 5/8 in test after test. Mine is relegated to the storage room.
     
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  8. Captain Kilowatt

    Captain Kilowatt Professional Amateur Staff Member

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    EXACTLY! Gain is not everything. I used to run a Diamond SG-2000HD antenna which is also a 7/8 wave. It was great for simplex mobile-mobile but was almost always beaten by a simple 1/2 or even 1/4 wave antenna when working repeaters high on the hilltops from the valley floor. I later switched to a Comet CA-2X4SR because of that and also the need for wider bandwidth. For somewhere on the great plains a 7/8 wave antenna is great. As for the "picket fencing" , or flutter, I actually had less with the 7/8 wave antenna then any other type.
     
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  9. SR385

    SR385 Active Member

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    I run a Diamond SG-7900 now and also have a Larsen 2/70B...it's been really interesting since I've been involved with a 440 repeater setup recently to experiment between the two antennas. 440 is quite a beast to figure out.

    I've definitely found the 7900 to be better for 2m simplex, but on 440, they both have their plusses and minuses. The Larsen shines on 440 with rolling hills and varied terrain, but the 7900 will kill it given long wide open clear shots to the machines. It's a tough call and I've been swapping them in and out fairly frequently trying to decide if either one is the 'winner'.
     
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