Pixie 2 cw transceiver kit

**kd0ekt** · Sun 25th Dec 2011, 00:18

Hello

I have just built a pixie 2 cw qrp transceiver and can't seem to get it to work. I was careful building it and have triple checked solder joints, polarity on the caps and transistors, etc. tried a new battery too. All i get is a rapid steady clicking noise for audio. It's a pretty fast click.

I'm still learning electronics and i dont have an o scope or component tester yet but i have tested what i can with a meter.

Anyone ever run into this or have any ideas?

Thanks!

**G4LNA** · Sun 25th Dec 2011, 08:05

I have had a look at the schematic and it looks pretty simple, from what you describe it sounds like oscillating around the audio chip somehow, often known as motorboating. At the moment all I suggest is to double check everything again, pay particular attention to C10 to make sure it is actually oriented the correct way around, as a matter of interest, what happens when you key the transmitter?

Can you take some pictures of it? Someone might be able to spot something you might have done wrong. It does happen you don't always spot your own mistakes, it's often a case of can't see the wood for the trees, I think everyone has done that in the past when building something, easy to do.

**kd0ekt** · Mon 26th Dec 2011, 21:02

I totally agree! I'm a computer programmer and that's the way it works with code too!

Here's the pic.

**kd0ekt** · Mon 26th Dec 2011, 21:23

Almost forgot your other questions. I double checked polarity on the 3 caps where it matters. When the key is down, the clicking stops. Also the components may look a little sloppy but none are touching so i dont see any shorts

**G4LNA** · Mon 26th Dec 2011, 22:11

Thanks for posting the picture, it makes it much easier. I have compared the layout you posted against this one I found and the yours looks the same, all the components are in the correct place and the orientation of them look the same, so at the moment I can't really work out why your one is not hackling, which is a bit frustrating. There so few components that it's highly unlikely it is a faulty component and you say you have checked for solder bridges. Do you have any test equipment that you are able to test if the crystal oscillator is working or not? Another receiver will do, you should hear it oscillating quite strongly.

Lets see if anyone else has any ideas.

**kd0ekt** · Tue 27th Dec 2011, 02:12

I have an rf probe that i made myself that i applied to the oscillator. Unfortunately my skills are not to the point that i have confidence in the probe anymore than i do the pixie, but it appears to be oscillating.

I tried listening for the carrier tone on the only hf receiver i have at the monent which is a cheapie "shortwave" but i couldnt find the tone.

I do plan to buy a better meter with a component tester and at least a frequency counter soon though.

**5B4AJB** · Tue 27th Dec 2011, 15:48

Check your capacitor values first, maybe you have placed one wrongly.

The image Paul linked shows the author using sockets for the LM386, now I've never had a problem with static and amp's, but you never know - same for the 2 transistors???

**kd0ekt** · Wed 28th Dec 2011, 14:21

Will do, thanks!

**kd0ekt** · Fri 30th Dec 2011, 00:17

Found a problem but apparently not THE problem.

C8 was the wrong cap. It was a .01uf. I swapped it out for a .1uf and it doesnt click anymore, but it does something even more strange.

I just have a steady shhhhhhhhh sound, but i can hear anything that touches the components or board amplified in my headset!

**5B4AJB** · Fri 30th Dec 2011, 02:03

Reduce lead lengths to an absolute minimum.
House it in a tuna can or small metal tin.
Make sure you have a good earth.

It's probably working fine, just nobody about, keep trying!

**kd0ekt** · Fri 30th Dec 2011, 02:36

I did consider the possibility it's working lol! I'll hook up an antenna and see if it picks anything up

**kd0ekt** · Fri 30th Dec 2011, 03:42

Lol! Ok hooked up the antenna and got a loud hum. So out of curiosity i disconnected one half of my random length center fed dipole, and guess what i heard? Stone temple pilots i kid you not! It's picking up commercial radio now!

**5B4AJB** · Fri 30th Dec 2011, 14:36

That kind of radio relies a lot on having a resonant antenna to begin with - you'll have a lot more success with a properly tuned input. Try knocking up a simple ATU and put that in line as well, but you'll need quite a long wire antenna to begin with.

If you have a local transmitter using a lot of power, there is hope, but the solutions may become a bit involved.