Morse Code Practice Oscillator

This video demonstrates a home built Morse Code Practice Oscillator, along with the reason for building one versus using a commercially available device.
The device demonstrated is based on the schematic in W1FB QRP Notebook page 145, labeled multivibrator. The RC circuit is not part of this schematic but if you Google RC filter you'll find good information.
Basically, you need to choose resistors and capacitors that will give you the time constant you want for the square wave frequency you wish to round to a sine wave..

[@KX4UL]

Nice job Richard! The oscillator you built sounds so smooth and steady. I had the MFJ-557 back when I was practicing my 13wpm CW for the General exam in 1993. I remember it sounded weak and sickly, but I forgot just how horrible it sounded until you keyed your MFJ-557...lol! Even the pricey MFJ-422C Bencher paddle/keyer combo sounded just as bad as the MFJ-557. I don't know why MFJ couldn't have come up with a better design for $189 back in the 90's. That would be like paying $340 today in 2021. Happy New Year!

[@HamRadioQRP]

If I were to buy a commercial oscillator today I think I would try this one from QRP guys qrpguys.com/qrpguys-code-trainer

[@vernonraines3002]

@@HamRadioQRP I bought this one about a year ago and it is a great unit for its size and cost.

[@n2dabloo]

Awe man, this is exactly what I've been looking for! I've got all the parts too. Salute from Mobile, AL KN4EQG

[@steveoshaughnessy3736]

I found this video because I have an MFJ-557. The sound is horrible and I wanted to see if was mine was broken or something. It's not, thankfully. FLDIGI won't even decode the MFJ, the tone is so bad. Thanks for the update.

[@AaronHuber]

Oh my that MFJ sounds like a dying duck! 73 de KO4GBD

[@jelisumichannel]

From malaysia love this video

[@warplanner8852]

Kinda prefer the 555 timer one. Reminds me of the old days when you'd work a guy who had crappy PS caps in his DX-20 and you'd give him a 599C.

[@HamRadioQRP]

The transmit tone from my old GRC/9 sounds worse than the 555 chiip :)

[@movecizetodobryfilm]

I build gen with timer 555 and it sound very nice. Dynamic speaker 40 Ohm from phone and have also socket for ear speaker. This device have frequency regulation and volume. This simple circuit. It can only operated on stright key, but for me it's ok. 73!

[@southjersey10]

Very nice. 😃

[@HamRadioQRP]

Thank you! Cheers!

[@Chiavaccio]

Great!!😀👏👏

[@HamRadioQRP]

Thank you! 😃

[@nsixvl]

Sure would like to know what value of R and C you used with your low pass filter?

[@HamRadioQRP]

I had to go open it up to look. I just used what I had laying around... 0.1uf-104 capacitors and 4.7k resistors

[@Conorkc86]

I am going to have a go at building this circuit. Any chance if you see this can you confirm that the 0.1 and 0.01 capacitors in the multivibrator are in uF? I have some N2222 transistors I am going to use in place of the 3904. Wish me luck 🙂

[@HamRadioQRP]

Yes , they should be uF values.

[@Conorkc86]

@@HamRadioQRP Cheers, thank you!

[@georgealbertacanadaeh1038]

can you please forward me the build info. Thanks! George

[@HamRadioQRP]

The device demonstrated is based on the schematic in W1FB QRP Notebook page 145, labeled multivibrator. The RC circuit is not part of this schematic but if you Google RC filter you'll find good information.