UPDATED NOTE, MAY 2008: This is an old video from a year or more ago, when I was just getting my feet wet with building some HF radio kits. The Pixie is a great place to get started. I don’t have a great deal of knowledge of radio theory, but this was educational in the visceral sense that I got to touch and feel the static and sounds of the HF spectrum. As far as being educational, well, it’s not. Just enjoy this panorama of my small circuit board built on the kitchen table. I’m licensed as a General, but I am a novice builder. I assembled a Pixie I bought on Ebay, went over all the solder joints. This video shows what I get when I have the transceiver on the bench. The crystal is marked 7.040, but I seem to get signal at 7.038 +/-. So, it appears the XMIT function works–at least better than receive audio. I get a buzz when 9V is applied with a small dry battery. However, when I transmit “V” from my TS850S, the Pixie is making audio of it. Things work–but not everything works. I hope YouTube will work as a forum to get me on the air. Any tips? Please leave your comments on how to stop this op-amp from motorboating, and how to rubber teh xtal with a simple RIT. NOTE: These notes are old, and the pixie is semi-operational as of May 15 2007. But I’m still futzing with it. Next up–the mighty ROCK MITE!
July 23rd, 2010 at 4:00 pm
I just finished this kit and cant get it to work, I was wondering if you could help? First off I bought two kits (GOOD THING) cause the first one was missing parts! In the instructions for circuit “L3″ Inductor 2.2uH 80meters(slvr,red,gld,gld)or40 meters(brn,blkgld,gld) soo I leave that circuit for last and the “inductor” they refer to looks like a “resistor” not a coil like I would guess is this normal? anyway I put in the one for 80 meters, put in an 80 meter crystal, cant tune it in on my sw!
July 23rd, 2010 at 4:00 pm
Your transmitter sounds normal you are keying a running oscillator. That’s the pixie design, not quite sure about the RX , it doesnt sound healthy. Have you tried keying the big Kenwood on this frequency to see what the Pixie hears??
73 good luck
July 23rd, 2010 at 4:00 pm
You should head over to qrz(dot)com and post this to the forums there. There are a lot of helpful people on the zed.
73, KE5NRH
July 23rd, 2010 at 4:00 pm
Definitely right! If you follow the chapters, I raised the voltage to stop the motorboating in the OPAMP, and things got better. I still haven’t made a contact on this rig–but I learned a lot.
July 23rd, 2010 at 4:00 pm
If this helps anyone building this project, mine also sounded like yours, and the problem with the RX was just the reversed diode.
July 23rd, 2010 at 4:00 pm
I still don’t quite understand but a good try and a very good start, genius!
July 23rd, 2010 at 4:00 pm
I bet the buzz in your audio is due to the 9volt battery. Add a filtering cap in the dc line and that should remove the buzz. This is a common problem with these small kits.
Robert
VE3RPF
July 23rd, 2010 at 4:00 pm
Great Pixie Videos. Can you give a link for where you got your kit? I really like having a memory chip to hold the CQ call and I see many different sites with kits. I have yet to find a kit with the memory modification. Did you add that later?
Thanks,
July 23rd, 2010 at 4:00 pm
Well, looking at this video more than a year later, I understand a lot. The oscillator in this circuit is “always on” but is frequency shifted on transmit. It’s a very basic circuit. The op-amp is motorboating, because I didn’t give it enough voltage. Well, you live and learn.
July 23rd, 2010 at 4:00 pm
You’ll have to show me photos.
If you can hear it in your scanner–key your rig that way. This minimalist rig is meant to be extremely simple.
July 23rd, 2010 at 4:00 pm
Ok I found one problem, lol in haste I forgot to solder the positive down lol! Heres the next problem the two contacts designated for the key when connected do not trigger the beep
only when one key wire is contacted to the end leg of the IC! I can hear it through my scanner!
July 23rd, 2010 at 4:00 pm
Well, inductors often look like resistors. That is normal. This circuit is SO simple, that any problems should be findable quickly.
July 23rd, 2010 at 4:00 pm
@kc7fys I have just built the kit and I seem to have similar issues. What voltage are you giving it now?
July 23rd, 2010 at 4:00 pm
QRP SDR transceiver KIT watch this video: f3hhHaSkowo and also this one: VXkEr4ZzebA