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Thread: Homebrew Bugcatcher Coil

  1. #1
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    Default Homebrew Bugcatcher Coil

    Homebrew Bugcatcher Coil

    You want to run legal limit mobile, better signal reports, run multiple bands off one antenna, than run a bugcatcher !

    Its really simple, so please follow along

    I originally built mine in march of 1996 its 8x8, hopefully this will give you an idea of what we are discussing


    I started off HF mobile with the ham sticks & found I was 33-55 rst at best
    Upgraded to a hustler multi resonant-er system & my signals increased 55-57
    The commercial bugcather I purchased changed that to 55-59 all the time
    So after my purchase I thought I can build that, & mine outperformed the commercial one so bye bye it went

    There is no wrong or right way to build one
    My friend AA1ME built one using copper screw on connectors for his base & top of coil
    Its only limited by your imagination & building skills
    Any one can really build one if they set their mind to it
    Go large or go home
    If you make a coil square do not have sharp corners as thats not good in coil theory

    Purists in the hobby will tell you that mine is incorrect & I know it that it is, my capacitance hat really needs to be at least 6" above the coil

    I am now helping Steve K1GMM design a coil for 40M, so all info is based upon this band for the remainder of the discussion here

    I used this site for its coil calculator ~ http://hamwaves.com/antennas/inductance.html just plug in your figures and away you go

    This will help you determine the size & inductance needed for your application

    Decide what wire diameter you will use, heres a handy chart to reference


    Here we decided to go with a 6" coil that is 8" long using 12gauge wire


    this gives us 85 microhenrys of inductance & a self resonating freq of 7.2Mhz


    I would also make the overall length a bit longer to compensate for the windings, better to have some excess
    so here is my design plan based around this info



    Remember a square coil is more efficient, however due to space limitations etc we cant have such all the time

    Larger diameter wire has more skin effect which translates in more DB's

    Please keep the bottom of the coil at least 6" above the roof line of your vehicle

    A longer whip on top of the coil will hear better than a shorter whip

    We can talk about capacitance hats later if need be

    So go build one & enjoy the HF bands while mobile

    73 AA1PR
    ExpeditionNorth.com
    expeditionnorth.boards.net

  2. #2
    OLC Member binrat's Avatar
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    I was going to comment last week on that thing but thought better. While it works, man is it ugly to the un-trained eye.
    I've been doing hamsticks / Hustler for a few years, then last year tried an Alpha Antenna "Alpha match" with a Wilson 5000 stinger for HF. I just found a good deal on a Tarheel II so its going on shortly.

  3. #3
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    Quote Originally Posted by binrat View Post
    I was going to comment last week on that thing but thought better. While it works, man is it ugly to the un-trained eye.
    I've been doing hamsticks / Hustler for a few years, then last year tried an Alpha Antenna "Alpha match" with a Wilson 5000 stinger for HF. I just found a good deal on a Tarheel II so its going on shortly.

    Yes, they are not pretty
    but they are efficient, all that large diameter wire equates to a better mobile signal
    its already rough enough just going mobile as you know
    I too had the hustler & hamsticks, theres just no comparison
    never used a screwdriver style antenna, so report back how that works
    ExpeditionNorth.com
    expeditionnorth.boards.net

  4. #4
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    Capacitance Hat project

    this is for my homebrew bugcatcher coil in all reality
    my cap hat is really too low, but I never thought of a way until recently to get it higher without and additional smaller mast inserted into the equation

    so here is my remedy...

    started off with the cut in half movie reel & and shaft collar lock


    next was to dig out the flux core welder & prepare a couple of tacks


    bolt was to keep the hole aligned, dont mind my weld I forget my reading glasses & was doing this blindly


    slide the newly created cap hat down the stainless steel 102" whipped & tightened down the 2 set screws


    reinstalled whip about 14" above the coil, so now the wave on the antenna should be correct


    & there she is all completed


    73
    ExpeditionNorth.com
    expeditionnorth.boards.net

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