Troubleshooting a Pixie QRP CW transceiver kit

They're simple, cheap with thousands sold. But how many sit around in junk bins after their builders failed to get them to work? This video gives some hints on troubleshooting the common Pixie QRP transceiver kit.
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[@MattExzy]

The Pixies are really awesome. I've made up three, blew a transistor in one, and put the others in various tins. I have one running off a small 2 cell li-ion 7.4v battery boosted to around 12v. They're just so neat to fiddle with. The Frogs CW seems to be more stable with a few more bells and whistles, but the kit I had was missing several components, but I had a few that were needed laying around anyways.

[@eugenecbell]

MattExzy, how did your transistor “blow”? Was it something you did or just infant mortality?

[@bill-2018]

Mine blew the o/p transistor and an electrolytic cap. and possibly the LM386. The track lifted trying to replace things so I got another one last year. 5.262 MHz and 350 mW out. I did get contacts before it blew up. G4GHB.

[@mcdeadsquirrel]

Just great!!! Have not seen such a clear demo since my old college days......'73 from New York State near the Canadian border.

[@eugenecbell]

I built one, not working yet. I had the zener diode in backwards, but fixed that. I will check all the components again for any things I did, but I think they are all correct. I don’t know how to test components in circuit. How can one test a capacitor in circuit? Transistor? If I had an oscilloscope I would hunt around for wave forms and voltages, but I don’t know what test points would be meaningful. Thank you for the video.

[@williamhutton4425]

Great video. I'm new to HF, QRP, and kit building--so A LOT I don't know!

[@IvanPassos]

Excellent Pixie Tranceiver QRP.

[@andyh5978]

Could have done with this video a couple of months ago as the kit took me 2 hours to build and then several days to troubleshoot! Turned out R1 was the wrong value - as Peter says a quality control issue, teach me not to check more closely!

[@Adui13]

Thanks for this. Unfortunately, my issue isn't addressed. Mine transmits, but the receive circuit has a constant audio tone oscillating much like a digital signal would sound

[@bill-2018]

Be aware there seem to be several manufacturers. I had no audio on mine. I theorised the audio was bypassed to earth and had to remove the audio jack socket to confirm it. The track needed cutting to prevent this. I wrecked the socket. Best dx on 5.262 MHz, 180 miles QSO with a SWL report on the same QSO from Utrecht at 220 miles. 350 mW out. Equivalent to 660 miles per Watt if you like. G4GHB.

[@Thejohnnyoshow]

my daughter just finished hers, it started to smoke haha :-) we will get another one and keep attempting until we get it right? i notice it seemed to be reverse when keyed it did not transmit when not keyed it transmitted then it started to smoke, any ideas :-) Im going to watch this video a few times and see if i can figure out where to start on this

[@Thejohnnyoshow]

the smoke looked to be coming from electrolytic capacitor right behind the bnc connector. but i do not see any burn damage yet.

[@DieGo-nl9il]

Good job,I just have making a pixie qrp,170mA tx,6v on 50ohms phantom resistor

[@eugenecbell]

Is an 8 ohm speaker suitable for this project? I’m using one, but it makes no sound.

[@jamilsouzagodoisouzagodoy1099]

O CW acabou faz anos...

[@tonywright8294]

My pixie worked straight away . Do some of the commentators realize it needs an aerial ? Also if you’re just testing it requires a load to prevent it blowing ! !

[@DeeegerD]

To avoid many problems - test each component before assembly if you have the equipment. You will need a multimeter that can also measure capacitance at the very least, and LCR meter is ideal as well as some way to test your transistors (there's an inexpensive Atmel microcontroller based transistor tester kit on eBay that will do most of these tests for you).

[@MarkPentler]

Did you film yourself playing back on a monitor? Your video production fascinates me, but the content is great :)

[@rowanlyle3642]

I know it is kinda off topic but does anybody know a good site to watch new series online?

[@xanderkashton1305]

@Rowan Lyle try flixzone. You can find it on google =)

[@dxexplorer]

Hi Peter. I wanted to ask one question as I'm lost in all the info available online. Does the version of the Pixie you are using in the video has automatic frequency offset on transmit and receive ? I'm asking because I found a lot of schematic online... that are using a third transistor for that. So before building the kit I was wondering if this one as it is has that by default... or I would have to make the changes by adding the third transistor instead. Thank you... as always. I wanted to email you instead but I forgot the address )) 73

[@vk3ye]

All versions of the Pixie have some sort of offset with a third transistor not required. It does this as the voltage on the Q2 emitter drops when it's keyed. Circuit here: w5nor.org/pixie/

[@dxexplorer]

That's great to hear. Thank you so much.... and wishing you an amazing weekend... as it's close ))

[@DudeInAMotorhome]

6:00 Since inductors (in this case L1-L3) are not polarized, it shouldn't matter which way I put them in, correct? I know in some instances that inductors used with transformers, sometimes have to be put in a certain way, but those inductors and schematics are usually marked as such. I didn't see that with the schematics for the pixie 4.1 unless... Anyways, any clarification is helpful. Received my first pixie a couple weeks ago and finally have it put together. Powers up fine and didn't let the magic smoke out. But not receiving any signals and not picking up transmissions from the Pixie on my SDR. So trying to track down the problem.

[@vk3ye]

correct - not polarised

[@DudeInAMotorhome]

vk3ye Thanks for the quick reply. Great videos by the way. Thanks for the clarification, helps rule that out.

[@jaumesevilla5642]

I've the same problem, ea3ze

[@eugenecbell]

The 33k resistor, supplied with my kit, was the color of the inductors, but measured about 33k with a VOM. Is this a resistor? Why is it the color of the coils? Is this common?

[@vk3ye]

If it measures 33k it's a resistor. Inductors are close to short circuit.

[@eugenecbell]

vk3ye, thank you for supporting my conclusion.

[@alanseidner3713]

@@vk3ye Mine is the same Way !!! thanks I would never of known

[@alanseidner3713]

my issue it it works but there is a strong AM station im getting 1240 or 1400 am they also transmit on 101.5 and 107.5 FM..... darn i want it to work !!!! SATIFACTION !

[@djpuffs]

Im struggling to find an appropriate antenna for the pixie, any suggestions? everything seems to be rated for vhf and uhf

[@vk3ye]

A half wave dipole or end-fed wire for 7 MHz will work. It will be 20m long. See my website vk3ye.com for ideas

[@SeAfasia]

I'm little confused about the point on schematic that I apply the AGC, a suggestion?

[@vk3ye]

You can build a very good receiver without an AGC. However putting AGC on a poor receiver like the Pixie is like (as we say in Australia) putting lipstick on a pig. Hence it's better to leave the Pixie as is and build a good direct conversion or superhet receiver and add AGC to that. But if you insist look up any audio amplifier circuit with audio AGC and use that.

[@SeAfasia]

Thanks...Peter 73!

[@joblessalex]

Have you ever made a contact on one of these?

[@ct7awb]

belkadog.com/2019/11/26/arduino-morser-e-pixie/

[@bill-2018]

My answer is a few years later to your question, but I made several contacts. QSO's at 60 miles, 80, 120 all several times and 180 miles with a SWL report from Utrecht at 220 miles. 350 mW out on 5.262 MHz. Unfortunately it blew up, p.a. transistor, electrolytic and possibly the LM386. The track lifted when trying to replace the transistor so I gave up and got another Pixie last year. G4GHB.

[@joblessalex]

@@bill-2018 Haha. I built like 3 of em and called CQ and got a reply at one point. Didn't know morse so I just ghosted back. It definitely did work!

[@bill-2018]

@@joblessalex Okay, thanks for replying. Yes they do work. Might be two or three c.w. signals received at once on 40m which is why I put mine on 60m, and put some activity on the band. G4GHB.

[@SeAfasia]

Hi Peter,a question Can we add an AGC?

[@vk3ye]

You could add audio AGC but the added complexity throws away the simplicity of the Pixie. If you're happy with adding more parts it's better to build a more complex and better performing receiver.

[@randomnessx3597]

im just getting a low buzz

[@ranchosinnombreannjimmy8427]

I am mailing you my radio shack 10 meter radio. Just make a video about how you fixed it.

[@ranchosinnombreannjimmy8427]

Im just starting building my first pixie, resistor colors don't add up lol

[@Paul_VK3HN]

I prefer a few extra parts and better reproducibility. But thats just me.