Miscellaneous babble – Page 3

DIY Festival and Amateur radio

The Amateur radio presentation I gave at the Charleston Library’s DIY Festival on Saturday went pretty well. Had about 10 people sit in on the presentation where I talked a little bit about what amateur radio is, what can be done with it, the licensing tests and then some construction techniques. To augment my presentation and emphasize the DIY aspect of ham radio, I brought in some of the projects I worked on including some of the Etherkit radios, my Arduino work station and some of the other circuits I soldered up.

There were a couple of people who were very interested, and asked a lot of questions, which was good. Hopefully they continue on to get licensed.

The DIY Festival itself was a pretty neat event. Lots of crafty-type things for the kids and lots of tables with people showing off their craft. Nice to see the Makelab Charleston guys there showing off a few things. One table had a Makey-Makey set up with bananas and carrots, which I saw a lot of kids having fun playing with. Looked like there was a great turnout of people for the DIY Festival.

Ham Radio at Charleston DIY Fest

I’ve been asked to give a presentation at the Charleston Library‘s DIY Festival that’s happening on Feb 28.

Sounds like it’s going to be a neat thing. My plan is to give a modified version of the amateur radio talk I’ve given at the last few BarcampCHS, and augment with a demonstration build of a crystal radio using some magnet wire and the 1N34A diodes I acquired recently.

Time to start messing around with building…

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.

Radio updates

What have I been doing in the amateur radio world lately?

Well, not a heck of a lot actually. I’ve even skipped a few of the big contests happening this fall.

Lately most of my spare time has been spent reading up on and learning about electronics and Arduino related things. I’ve spent a little bit of time playing at the workbench. Nothing terribly complex. Just soldering together simple circuits and practicing ugly construction techniques.

My reading list for the past few months:

EMRFD
Ham Radio for Arduino and PICAXE
Arduino for Ham Radio
Solid Sate Design for the Radio Amateur
W1FB’s QRP Notebook
ARRL’s Hands-On Radio Experiments

I’m no expert yet, but I think I know a little more than I did a while ago.

In the next couple of weeks, the plan is to turn the guest bedroom into a ham shack/guest bedroom. First we’ll empty out the room, paint the walls and then move everything back in. I’ll have to get back into the crawl space to pull the coax out, but the antenna feed point will be closer to the radio which means a shorter coax run that won’t have to go under the house.

The guest room also stays a lot cooler than the office so playing radio during the summer will be a lot more comfortable.

Tower lowering

I was fortunate enough to have the opportunity to participate in a tower lowering party this afternoon and met a group of really nice hams in the process. A local business with a 140 foot tower didn’t need it anymore and offered it to anyone for free as long as they took it down. One of the local hams took them up on the offer and today the tower lowering began.

Having no experience with towers, I was eager to see one up close, watch how one gets taken down and do what I could to help out. By the time I got to the site, the antennas and hardlines had already been taken down (a task that took up most of the morning). Here’s the ground crew and two of the guys up on the tower working on undoing the top section.

Lowering a 140' tower — Lowering a 140′ tower

I counted 14 sections of tower, which I was later told was Rohn 45 (commercial grade stuff). The guys climbing the tower were working pretty high up. The top section of the antenna turned out to be pretty stubborn to get off, but eventually it came off and made it onto the ground.

It took the bulk of the afternoon, but eventually three more sections of tower were brought down. I guess after being up for 30 years, those sections of tower get stuck to each other pretty good.

I didn’t do any tower climbing (left that to those more experienced than me) but I did help out on the ground with lowering the sections. As a relatively new ham, it was a great learning experience for me just being able to watch the process. Got to see how a gin pole works, see just how much work it is to take a section down and handled tower sections.

Four sections of tower down, ten more to go. Looking forward to the next session.