Practicing with the Begali

Got my Begali Camelback straight key wired up with a standard 3.5mm TRS cable, and made up an adapter cable to connect it to the Heathkit HD-10 keyer.

Morse code keys and bug connected to a Heathkit HD-10 electronic keyer

I’ve been really enjoying practicing Morse code with the Camelback. The solid, weighty base gives it a super stable feel and a nice satisfying thunk-y sound as opposed to the more clack-y sound from the J-38 key. I’m sure if I mounted the J-38 on a more solid base, it might also have a nice thunk-y-er sound. I’ll have to look around for something heavy to attach the J-38 to now.

The Camelback is hefty enough that it doesn’t move around while I’m keying. The Vibroplex bug is also pretty hefty, but will slide around a bit while I’m using it. I probably need to replace the feet or put some grippy pads on them to keep it from sliding around.

An Instructograph

While I was rummaging around through the club’s storage room yesterday, I came across an old Instructograph machine. I’m not sure how old this particular unit is, but it looks like it has definitely seen better days.

Instructograph label
Instructograph label
Instructograph
Instructograph
Instructograph
Instructograph

It’s a paper tape based Morse code trainer with the Morse code encoded as holes in the paper tape. Along with the Instructograph were nine tins containing other tapes. Seven of them were rusted closed so I didn’t try to force them open. A couple were left open, including the one already on the Instructograph.

Instructograph tape tins
Instructograph tape tins
Instructograph tin
Instructograph tin
Open instructograph tin
Open instructograph tin

The Instructograph is essentially just an automatic straight keyer with an audio oscillator. As the paper tape moves between the contacts, the key is closed where the dots and dashes are punched out of the paper and generates the tone. The tapes are double-sided, so when you finish playing one, you just flip it over, thread it back onto the machine and play the other side.

Instructograph contact switch
Instructograph contact switch

I think the tape speed would have been controlled using this lever on the panel.

Instructograph speed control
Instructograph speed control

No idea if the Instructograph still works or what kind of condition the innards are in. The paper tapes are in somewhat delicate condition and I’m not sure if they’d hold up to much playing anymore if the Instructograph did work.

Morse code at 25 wpm

For a while now, I’ve been listening to Chuck Adam’s (K7QO) code course. It’s a good, methodical course that first takes you through each letter, with a cumulative test after every second letter. You get lots of practice hearing each letter by the time you get to Z. I’m starting to recognize most of the letters up to K now.

The course sounds like it’s recorded at somewhere between 15-20 wpm. For most people that’s probably plenty fast enough but it’s just slow enough that my brain still wants to count the dits and dahs and then convert to the corresponding letter rather than just listen to the rhythm of the sound.

What I needed to do is convert or generate a new set of files that plays the code faster. With a bit of experimenting at lcwo.net, I found that 25wpm was where my brain stopped trying to count dits and dahs, letting me focus more on the sound of each letter.

A little bit of searching brought me to a program called ebook2cw by Fabian Kurz/DJ1YFK, who also happens to be one of the people behind lcwo.net. From there, it was a trivial exercise to feed the answer files from Chuck’s code course into ebook2cw to generate a new set of audio files (OGG turned out to be about half the size of MP3) at a character speed of 25wpm and effective speed of 15wpm.

Here’s the shell script I used to generate the OGG files

#!/bin/sh
for file in *.txt
  do /opt/bin/ebook2cw -O -p -o `basename -s .txt $file` $file;
done

Do this in the directory where you’ve extracted the text files from K7QO’s answers file and you’ll end up with a bunch of .ogg files. Then copy them to the media player of your choice (if it can’t handle OGG files, it’s time for a new player). If you insist on MP3 files, just drop the -O parameter. The file names will have some trailing 0’s tacked on before the extension (chapter numbers automatically added in by ebook2cw) but it doesn’t affect anything.

Code practice oscillator completed

The panel mount potentiometer I used in the CPO was missing the nut needed to secure it into place. After determining that I needed a 1/4″-32 thread hex nut, I went scouring my Radio Shack and hardware store bins looking for some.

At Radio Shack, I found a bag of assorted hex nuts in their parts bins, with the right thread number, but none of them were smaller than 5/16″. Next stop was a big box hardware store. There I found 1/4″ nuts, but the finest thread they had was 28. The hex nuts they did have with a 32 thread were all #10 or smaller.

Then I went to a couple of the smaller box hardware stores. Much larger selection of nuts and bolts, but still the same problem as with the big box hardware store. Nothing with a finer thread than 1/4″-28, and nothing larger than a #10-32.

So much for instant gratification.

Thanks to a suggestion in the Google+ Ham Radio Homebrew community, I found some (Bourns H-38-1) at Mouser Electronics. Ordered 20 of them so I’d have extras in case I needed some for later. They arrived a few days ago and now my NT7S code practice oscillator is complete!

NT7S code practice oscillator
NT7S code practice oscillator
NT7S code practice oscillator
NT7S code practice oscillator
NT7S code practice oscillator
NT7S code practice oscillator

Code practice oscillator enclosure

The mini-breadboard version of the NT7S code practice oscillator along with 9V battery fits perfectly into an Altoids tin (the preferred enclosure of tinkerers everywhere). This evening I spent some time wiring up the board to the jacks and power switch.

When I plugged in the headphones and my straight key, I was greeted with a continuous tone, and nothing happened when I tapped the key. Crap, I must have a short somewhere. After a bit of looking around on the board, I went back into the house to grab the schematic, and then realized I had plugged things into the wrong jacks. Swapped the headphones and key and got nice sounding tones when I tapped the key, just as expected. Works great and everything sits in the tin nice and securely. The battery slides around a tiny bit, but that’s not a big deal.

NT7S code practice oscillator in an enclosure
NT7S code practice oscillator in an enclosure

Now I can bundle up my straight key and some headphones and practice wherever I want.