Tag: morse code

Mini code practice oscillator

I’ve been wanting something small and portable that I could carry around with me for doing Morse Code practice. The Heathkit HD-10 oscillator is fun to play with, but kind of big and chunky to haul around. The ARRL code oscillator is small and portable, but the buzzing sound gets kind of unpleasant to listen to after a while.

Then I found Jason’s/NT7S schematics for his code practice oscillator (CPO) in his blog and decided to build one. I gathered up the pieces and tried to assemble it on a breadboard a while ago but got distracted by other things and never quite finished.

With the acquisition of some solderable mini-breadboards from SparkFun and the perma-protoboards from Adafruit, it was time to get back to the project. The Sparkfun mini breadboard fits perfectly on top of one of their modular mini breadboards so I put the solderable breadboard on top of the modular breadboard and started laying out the components. Then, once I’m done all I have to do is carefully lift the solderable breadboard off the modular breadboard and then solder away.

After spending some time staring at the schematic and the breadboard pondering how to lay things out, I remembered a suggestion from the kit building forum at the ARRL Centennial Convention. Build modularly and test as you go so that if something doesn’t work, it’s easier to isolate the problem area.

With this in mind, I started with the power section of the schematic and laid that out in one corner of the board. Add power, flip the switch, LED comes on. Perfect!

The CPO is small and simple enough so that the rest of the circuit pretty much falls into place after that. After a few hours of placing components, double checking placement and debugging, I finally managed to get it working.

NT7S Mini-CPO
NT7S Mini-CPO
NT7S Mini CPO
NT7S Mini CPO

With a few wires, I connected my straight key and connected straight to the plug of some ear buds I had lying around. Tapping on the key yielded some pleasant sounding tones, and turning the pot changed the volume (and frequency a tiny bit).

NT7S Mini CPO connected to the straight key
NT7S Mini CPO connected to the straight key

Now all I need to do is solder everything into place, add some jacks and stick it into an enclosure.

A nice, easy build and I was able to do it all with parts I had on hand.

From breadboard to Perma-Proto board

First I took the little Morse code kit and put it onto a breadboard. Over at adafruit.com, they have these neat Perma-Proto PCBs that are circuit board versions of a breadboard. Makes it easy to transfer something you’ve assembled on a breadboard to something a little more permanent.

I picked up a few a little while ago with the intention of transferring the breadboard version of the  Morse code kit to a Perma-Proto board and finally got around to it this evening.

Morse code practice oscillator
Morse code practice oscillator

A nice relaxing couple of hours spent melting some solder.

Connecting the straight key

After going through the manual for the HD-10, I learned that the terminals on the rear of the HD-10 could be used to attach a key. So off to the garage I went to put some terminal connectors on some wires to use to hook up the J-38 key to the HD-10.

It took a couple of tries before I figured out where the wires were supposed to go on the J-38. There are lots of pictures of J-38 keys on the internet, but not too many that show how the wires are supposed to be attached (the terminals are the two on the inside).

J-38 straight key and HD-10 keyer
J-38 straight key and HD-10 keyer

With everything connected, tapping the key made the keyer make noises and I managed to make some Morse Code sounding noises with the key. Now they can sit on the desk next to me so that I can practice tapping out Morse Code whenever I feel like.

I still need to take the key off the base and clean it up a bit, and then make up a cable that I can use to plug the J-38 into the radio with. Also thinking about seeing if I can find a nice block of wood to attach the J-38 key to for a more solid base and to elevate the key a bit.

Morse Code key 2

The kit I built has been pretty fun to play with, and I’ve got about 6 letters so far that I remember the code for and what letter it represents. There are a few more codes where I have to think about what letter it represents. I’ll be able to start testing myself by listening to some code and trying to interpret it.

In the meantime, I thought it would be cool to start experimenting with the basic kit. Stopped by Radio Shack yesterday and was able to find all the circuit components and a breadboard to recreate a second key. The plan is to lay out the key on the breadboard and get it working, then experiment with some mods. First mod I’d like to try is to insert an LED that lights up when the key is pressed so that it blinks as well as beeps. Then maybe add some volume control. I think there’s a good bit of room for playing with the kit.

I’m also going to need some parts bins for the workbench.