CPO in enclosure    N4YG DDS Code Practice Oscillator: This kit is a tone generatornot a keyer.  The tone produced is a pleasing one, a sine wave or pure tone, not a square wave.  Audio frequency is adjustable over a broad range and the direct output to speaker is loud and clear.

    On first assembling the kit, the built-in amplifier didn
t work so I added a ‘temporary jack to use an external amplifier. Later when the internal amplifier was working I left the amplifier jack in place and added a speaker jack.  I also added a small relay to key the CPO from the one-watters transmit signal. This might be better done electronically. The power supply is a 9 volt battery and 7805 regulator.

    At the Charleston Hamfest I picked up a grab bag of PCB
’s and since then have used one of them to consolidate the oscillator and mods onto one board, making a somewhat neater package.  At the same time I replaced the relay with a DPDT version in order to use the second pole for muting a receiver. The photo and video demo are of the original messy assembly, however.

    N4YG DDS Code Practice Oscillator Demo: CPO/CPO-Demo.mp4 
 


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