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Buying An Astroplane

Discussion in 'CB Antennas' started by HomerBB, Dec 4, 2010.

  1. HomerBB

    HomerBB Well-Known Member

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    Unless things change between now and Monday I will be picking up an Astroplane that looks like the photo except the lower mounting bracket is missing. That shouldn't be difficult to fit. I'm paying $25. Fair price?



    [​IMG]
    #1
  2. Marconi

    Marconi Supporting Member

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    Homer, a very good buy if the antenna is in good shape.

    A lot of people claim this is a very good antenna mounted low to the Earth. That may be true, but IMO it has to be out in the clear period. I find that it is affected just like other vertical monopoles that are too close to anything near the bottom end of the antenna. This antenna should be at least high enough for the full antenna to be higher than most of any surroundings like homes etc. or you might expect some ill-affects.

    I have my Top One at 45' feet to the tip and until I got my Sirio Gain Master, I thought this antenna was one of the two quietest vertical antennas I own.

    I also think the antenna matches best with a 1.25"-1.50" mast installed, which doesn't come with the antenna as sold. I also think the mast should be at least 10' and longer is preferable.
    #2
  3. CDX-007

    CDX-007 Transducer Fanatic

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    Why don't I run into great deals like this...? ~;^0 )>

    THIEF! (y)

    #3
  4. HomerBB

    HomerBB Well-Known Member

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    I thought the price was good, although he hinted at $40. I held him to the first price we discussed. It's a bit out of character for me to buy a base antenna, but I'm making an exception for this one. It needs cleaning up, replacing the hardware with SS, and try to put the missing bracket back in. It may be a little misshapen near the top, but I won't be sure until I get it off the mast it is on and in my hands. I'll pay particular attention to the feed point, and put it on a center mast as you've suggested.

    As the weather is quickly closing in it will be a toss up whether I'll be able to move quickly enough to work this one out. I wish I had Houston weather to work with in the winter. As a boy growing up there I recall Christmas in short sleeves and sunshine.

    I can hardly wait to look it over up close and personal. I've been talking to him on and off for nearly a year. He finally said yes today.
    #4
  5. HomerBB

    HomerBB Well-Known Member

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    I'm dodging the coppers now!
    #5
  6. CDX-007

    CDX-007 Transducer Fanatic

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    [​IMG][​IMG]
    #6
  7. HomerBB

    HomerBB Well-Known Member

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    :laugh:
    #7
  8. Marconi

    Marconi Supporting Member

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    Do you have an idea for the missing bracket? I think that Starduster posted some brackets on his thread on the AstroPlane or the Top One some time back if you recall. If not, I have a close up of a bracket off an old knockoff called the Top One sold by Coopers. I think I posted a schematic in "mm" if you need dimensions. I recall I checked some measurements and I think they were right on the money. If you can't find the images, let me know and I will repost them.

    In case you don't know, the AstroPlane shows an electrical short over the whole antenna when fully assembled.

    The feed point shows open isolation between the shield and center conductor only when the antenna is unassembled or the hoop is not attached to one or both of the down radials. Otherwise the feed point will show a direct short which may look stange on first glance.

    Also don't let the supporting mast project above the mounting plate.

    The bow in the down radials is critical to matching in case this support part is missing. This support is also insulated from the radials, and it also provides for the necessary bow in the radials. The insulated bracket can be mounted directly to the mast however.
    #8
  9. HomerBB

    HomerBB Well-Known Member

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    Thanks for the info. I'll get back to you on the bracket photos/specs.
    I will certainly need critical measurements for those down radials spacings.
    All of this is good information.
    #9
  10. TonyV225

    TonyV225 Supporting Member

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    G:eek::eek:D SCORE!!
    #10
  11. HomerBB

    HomerBB Well-Known Member

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    (y)
    #11
  12. Starduster

    Starduster Member

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    The braket clamps double as the tube splice clamp for the down tube.

    Attached Files:

    #12
  13. CDX-007

    CDX-007 Transducer Fanatic

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    I helped a friend who bought one used and without that lower fiberglass rod between the lower legs, and we ended up using 3 strings of dacron line tied onto the ring & glued 120° apart and then tied onto the center mast, and his SWR was 1.15:1, and it works all TVs as well as expected. [​IMG]

    I'd recommend wrapping a common mode current choke in the coax a few feet below the ring.
    #13
  14. HomerBB

    HomerBB Well-Known Member

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    Will do
    #14
  15. HomerBB

    HomerBB Well-Known Member

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    Here it is, at last:
    [​IMG] [​IMG]
    [​IMG] [​IMG]
    [​IMG]
    Last edited: Dec 7, 2010
    #15


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