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Thread: Hendricks BITX20A AGC, S-meter Mod

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  1. #1
    Join Date
    Jan 2000
    Location
    Chatsworth, CA
    Posts
    623

    Default Hendricks BITX20A AGC, S-meter Mod

    Hello Builders!

    I have been looking all over for an actual schematic
    for a HENDRICKS BITX20 AGC Mod. I get lots of
    hits about people who say they added the AGC
    Mod, S-Meter Mod, etc, but they contain no other
    information other than "I did this Mod".

    I would also like to add an inexpensive S-Meter. The only
    actual schematic I found was for a 5 segment LED
    bar graph. A good start (and a fall back plan)
    but I would prefer an analog meter if possible.
    Again.....I have seen photos and You Tube videos
    of units with a CB type S Meter added but no other info.

    Anybody done these mods or seen a schematic?
    It would really make my day.
    TNX ES 73, Ken AD6KA
    kenp <AT> socal.rr.com

  2. #2
    Join Date
    Feb 2004
    Location
    Bakersfield, CA
    Posts
    4,442

    Default

    I'd check with these folks and see what they have to say;
    One of the great things about the BitX20 is that there is a discussion group for BitX20 builders located at http://groups.yahoo.com/group/BITX20. This group not only provides help for those building BitX20's, but also provides discussion about modifications.
    Hope this helps
    73
    Gary

  3. #3
    Join Date
    Feb 2004
    Location
    Bakersfield, CA
    Posts
    4,442

    Default

    I did some more digging and found somethings that might be helpful. There's a description of a s-meter circuit here; http://n8wq.blogspot.com/2012/04/imp...-part-2-i.html.
    This is the schematic for it;

    S-meter+schematic.jpg

    Another one here; http://www.southgatearc.org/qrp/audiometer.htm.

    s-meter.gif

    If you look at how they derive their signals and how they control and amplify the signal these circuits are almost identical.
    And one that actually uses a couple of IC's and yes you can still get them. You may only need the circuitry from C5 on.

    AGC_S-meter_PY2MG.gif

    I'm sure if you wanted to find other circuits doing an internet search will net you a number of them.
    Got this one from this site; http://www.qsl.net/va3iul/Homebrew_R...sign_Ideas.htm. Loads of stuff there.
    Hope this helps.
    Have fun
    73
    Gary
    Last edited by KO6WB; 10-25-2012 at 02:38 PM.

  4. #4
    Join Date
    Jan 2000
    Location
    Chatsworth, CA
    Posts
    623

    Default

    Thanks for all the great resonses guys!
    They are a geat help.
    73, Ken AD6KA

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