Code Practice Oscillator Kits

Nashua Area Radio Society Topics In All Forums CW and QRP Forum Code Practice Oscillator Kits

This topic contains 2 replies, has 2 voices, and was last updated by Layne AE1N Layne AE1N 1 year, 7 months ago.

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  • #5379
    Layne AE1N
    Layne AE1N
    Participant

    Code Practice Oscillator Kits

    [NOTE:  DISCLAIMER: This is for info. Neither Nashua Area Radio Club nor myself necessarily endorses this product  … caveat emptor.]

    CPO1 Code Practice Oscillator Kits For Sale – 7 available
    Price: <b>$25 each</b> which includes USPS priority mail to the contiguous 48.
    PayPal Only

    Contact me at <b>[email protected]</b> for my PayPal email address.

    I developed this code practice oscillator for my own use and decided to kit a few of them. I sold some on eBay and now have 7 kits left that are already boxed. I don’t have any current plans to kit any more of them.

    The schematic and assembly manual are available here: http://ab5cw.com/documentation/

    Note that these are kits and require assembly/soldering. The photo shows the completed oscillator.

    cpo1.jpg

     

    cpo1_stack.jpg

    A printed manual is included in the box. If you have any issues during assembly or use, please let me know.
    Steve AB5CW

    Layne AE1N

    #5401
    Mike Ryan
    Mike Ryan
    Participant

    I took a quick look at the circuit diagram and it appears to be a Twin-T Sine wave Audio Oscillator followed by an NJM386 audio amplifier. The board should work well with a STRAIGHT KEY and DOES NOT INCLUDE a keyer chip to work with Single or Dual Paddle keys. FYI – it would also work OK with an old fashioned Vibropex BUG as the dits are generated by a bouncing spring contact.

    Sine waves are more comfortable to listen to than the square wave audio source. The output stage of the NJM386 audio amp can drive a set of stereo headphones. The circuit shows an available connection for a small external low power speaker (not provided) which is disabled when headphones are used.

    The circuit board and moderate number of components used with the board might make this a good kit for hobbyists with limited soldering and assembly skills. It includes a number of U shaped wire test points that could be helpful in troubleshooting problems and also learning more about the design and operation.

    A diode is included in the power lead to protect against reverse voltage polarity (if you put the battery in backward). Includes on/off switch and LED power on indicator.

    Note: Oct 2016 QST article on PG42 shows a wide range Twin-T circuit designed to cover a much wider range than just audio. Much more of a test instrument, but you may still find the article interesting.

    Hope this was helpful.

    - Mike (K1WVO)
    Nashua Area Radio Club

    k1wvo@arrl.net
    Visit us on the web at - https://www.n1fd.org

    #5419
    Layne AE1N
    Layne AE1N
    Participant

    Thanks for the Technical follow-up Mike!

    Layne AE1N

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