Archive for December, 2009

Okay, here’s a preview of my project plans for Christmas break! My goal is to make a fun and comfortably functional HF CW transmitter / direct-conversion receiver capable of working any HF band by merging the incredibly simple and cheap (~$10) Pixie II CW transceiver with a SI 570 digital programmable oscillator controlled by an ATTiny 2313 microcontroller! (it’s often used in SDRs controlled by USB as seen here).

AUDIO FILES!!! [80m.mp3] and [40m.mp3] are already ready already!

Preliminary work demonstrates a functional receiver powered by a crystal. I don’t think the currently-configured digital oscillator is putting out enough power to run the circuit, but it’ll take more time to get that up and running. For now, here are some photos of what I’ve got working and real sound clips of the thing are below. I’m happy with the case I built it in (thanks Ron!), and happy with my level drilling of the holes for power, output, and the CW key!

Briefly, the device is powered by a 9V battery. It’s hooked up to an 80m dipole antenna. Output is fed into a computer sound card for amplification / PSK31 analysis.



The internals reveal that it’s a simple circuit powered by a single crystal. More crystals are tucked in the case, stuck in foam, for easy transport.

Decoding of PSK31 is happening here, using output from my circuit with the 40m crystal in it.

AUDIO FILES approx. 1 minute in length from my circuit:
>> [80m.mp3]
>> [40m.mp3]

Wish me luck! This project is just beginning…

now for a random video/song:

Yeah, I said it. I have a couple minutes to write tonight so I decided to record what I’ve been up to just for the record. I’m approaching the end of my first semester of dental school. I had a very shaky start, and quite a few low grades in the beginning. Luckily, things turned around for me a few months ago. I have a small group of people I study with, I’m getting decent grades, I seem to be doing well in the dental lab, and I actually have a wee bit of free time to purse personal interests (namely programming [python, C, and perl], amateur radio, and a [declassified] top-secret SheevaPlug project). However, as of now, dental school is unbelievably boring to me. I’m sure it will become more interesting with time, but right now it’s nothing but monotonously memorizing boring facts. I’m hanging onto whatever little side projects I can just to keep myself sane. So, with that being said, I’ll get back to my work. I’m posting a short interview I found interesting. This is the guy who runs IsoHunt.com.