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Ramsey PR40 440Mhz Preamp kit

Discussion in 'Home Brew' started by Moleculo, Jul 17, 2009.

  1. TMI

    TMI W9WDX Amateur Radio Club Member

    May 6, 2009
    Likes Received:
    Negative. The passes I've been working lately have picked up So. Cal to Alaska. I need to work some lower angle passes to pick up more mid-west and east coast contacts. Farthest to date from western Washington has been Ohio for me.

    I'd also like to get up on a hilltop and work a low pass to the west, and see if I can hear any Hawaii stations.

    This is just a whole lot of fun with 5 watts :D

    Tom / W3ROK


  2. dudmuck

    dudmuck Active Member

    May 21, 2007
    Likes Received:
    Tuning up this preamp could be easier if they included a variable capacitor for the RF input C2.
    But for a $15 kit, i doubt that would be practical.

    i'm not sure if they use the 2SC2498 or the 2SC2570A, but the latter would be better due to lower noise.

    The best of the best preamps use the Agilent ATF10136 gas-fet or similar.
    you could google for that and find all kinds of incredible LNA designs.
  3. KB3TQO

    KB3TQO Member

    Mar 26, 2010
    Likes Received:
    i also purchased this kit. so far the construction has been simple. i have found myself at a standstill with the connection between the board and the bnc connectors. the manual suggests using RG-174 but i dont have any nor do i plan on buying 1ft for 15 cents and spending $6.oo on shipping. i do however have plenty of RG-58 lying around. would this work for this kit? and if so, do i only use the center conductor for both connections on each connector or do i use the shield as well?
    im such a newb but trying to learn,
  4. Qwazyone

    Qwazyone Active Member

    Jan 25, 2009
    Likes Received:
    If you look at Moleculos pictures on page 1 of the thread, in the pic below "everything installed in box and ready to go" shows where the shielding gets connected to the board(just solder the shielding where the green wires for his BNC connectors are)
  5. n3ibx

    n3ibx Member

    Apr 22, 2011
    Likes Received:
    Hello, I saw the Ramsey kits too, and am very interested in them. Please let us know how well yours performs once you have it hooked up and can make some tests with it.

    I'm very impressed with the low noise figure they give in it's specs. I'd rather have a preamp that has a little less gain and less noise than something that has a lot of gain with corresponding noise that comes in with it.

    Joe Cro N3IBX
  6. Moleculo

    Moleculo Administrator
    Staff Member

    Apr 14, 2002
    Likes Received:
    It does work well for my intended use. I strap it on the handheld yagi and use it for satellite work. It really helps on the low elevation passes and you also start picking up the bird closer to the horizon. Is it absolutely necessary? No, but every little bit helps when you're doing this with a handheld.


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