11:31:40 pm on 2/4/12

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CEJ, QRSS, and Life Recontemplation »


HF CW on the Cheap
611 words | Posted on December 10th, 2009
Scott was 24.21 years old when he wrote this!
Filed under: Circuitry, General, Microcontrollers, Radio

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!
cw_everything
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.
cw_coke
cw_close
cw_open2
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.
40mPSK
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:





This entry was posted on Thursday, December 10th, 2009 at 11:44 pmand is filed under Circuitry, General, Microcontrollers, Radio. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.



4 Responses to “HF CW on the Cheap”

Kyle wrote the following at 10:51:15 PM on December 13th, 2009

Is that your gear pictured or just a prototype…?

Scott wrote the following at 10:58:23 AM on December 14th, 2009

That’s my actual, functional gear. The MP3s I uplaoded are from *that* device pictured. How cool is that?

Kyle wrote the following at 04:46:17 PM on December 15th, 2009

dude that is wicked sick….btw did you get my email?

weds-thurs-friday wrote the following at 01:16:13 PM on December 29th, 2009

NIce one! Clean.
Constructive criticism…shorten crystal leads to min, especially for transmit.
Stray capacitance will affect proper rec/trx frequency.
Keep up the good work, Peter.

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