- September 20, 2016 at 7:40 pm #5379
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.
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.
A printed manual is included in the box. If you have any issues during assembly or use, please let me know.
Layne AE1NSeptember 21, 2016 at 9:18 pm #5401
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.September 23, 2016 at 12:16 pm #5419
Thanks for the Technical follow-up Mike!
You must be logged in to reply to this topic.