Passive CW Audio Filter - 600Hz / 800Hz CW Audio Bandpass Filter
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- Опубликовано: 30 май 2024
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Build a simple passive CW audio filter with a handful of components. You can always turn it into an active CW bandpass filter if used with a simple audio amplifier.
73, YO6DXE.
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Наука
7:41 someone told me a fly have ability to travel through monitor to any other place in the world and back
Nice construction - clear, rugged and simple. I guess resistor not only bypasses but also affects the coil Q
You are right on the flies hahaha. They are so annoying... but I can't put up with mother nature... 🤣. On the potentiometer, technically yes it should affect the Q of the inductor and actually the Q of the entire filter. I still can't believe how effective it is though. 73, YO6DXE
I love the simplicity of this. sounds like it's working perfectly.
I think I should make one of those.
Vy 73 de Jan, OZ9QV
I can't believe how well it gets rid of the interferences. It still impresses me. 73, YO6DXE
Saudações !!! TKS & 73 !!!👏👏👏
Saudações da Transilvânia, meu amigo. 73, YO6DXE
Ciprian, you're right. So simple and very effective. Many years ago I installed such a filter in my station loudspeaker. Years after that I sold the device. You've made me install such a filter again in the loudspeaker of my current station 🙂
mny 73 Bernd, DF7PI
Hehehe. Indeed.. I am also impressed on how well it works. I want to build an audio amplifier to use it with simple low audio output transceivers and have this filter incorporated into the audio amplifier. I think it would be nice to have some filtering especially that simple transceivers are wide open on the input. Glad you also like it. 73, YO6DXE
It's very beautiful project. I like how it turned out. also love background wallpaper 😁. good luck 4L1LAT
I also like the way it turned out. Thank you so much. The background paper is from Sweden ... that is where the camper comes from 🤣🤣. 73, YO6DXE
Well done!! The filter works absolutely amazing. It is a nice thing to add to the hombrew receiver projects. I really like the case with the pcb by the way. 73
I think I know someone else that likes to build cases from PCB boards hahaha. Thanks Nikos. Is really nice filter indeed. I want to build a standalone amplifier with this filter included ... with a vintage look. I just need time haha. 73 buddy and happy DXing.
@@dxexplorer haha i am also wondering. I think i have to get back on building some projects this summer. Good luck
@sv2tcb Hahaha. Good luck with the projects to you too Nikos. Most of my stuff is in boxes now... we sold the old house and moved out. A little harder for me to build much stuff.
@@dxexplorer I understand, i hope you find some time for some projects this summer
@sv2tcb I hope so too. 😁
The nice thing about a passive filter is that there is minimal ringing. It's just a clean sound.
Yes... and it works really well comparing to some other schematics I found based on transistors or IC's. 73, YO6DXE
A pcb como caixa ficou legal, é ótimo para RF tem uma boa área de terra, pra mim seria mais barato usar chapa de alumínio, se bem que essa montagem é pequena e usa pouca pcb. Eu precisei enrolar um indutor de 100mH para um filtro de 5kHz para um regen uma vez, mas usei aquela bobina pequena de ferrite usada nos filtros de saída dos amplificadores classe D, deu bastante trabalho enrolar num carretel tão pequeno. 73.
Eu também queria enrolar o indutor em algum toróide primeiro... mas decidi desistir depois das primeiras 80 voltas... foi um pesadelo jajaja. Os telefones antigos tinham indutores de 77mH dentro, quero dizer, os analógicos. Infelizmente não tenho nenhum desses 🤣. O recinto, inicialmente eu queria fazer em alumínio e madeira, mas saí de casa recentemente e estou morando em um trailer no momento... então não tenho ideia de que caixa estão minhas coisas 🤣. 73, YO6DXE e tenha um fim de semana incrível.
Looks good and sounds good too.
Thanks so much. I really like the way it sounds too. 73, YO6DXE
from what I can hear that really sounds great
Thnx for sharing
Thanks Khalid. Is the old filter that I built long time ago for the Sputnik. Now it looks and works a little better though. I really like it. 73 my friend, I hope is all good with you.
Very cute and shiny design,I like it and yeh that is working great ,thnx for update
Thanks as well for watching. Ohh yes I love it 😁. 73, YO6DXE
Nice Work! I also uploaded some video clips on my channel about CW filters. OpAmp version and DSP version.
Thanks so much. Well then I have to come by and watch the videos 😄😄. 73, YO6DXE
Your receiver is drifting like crazy.
Is the Little Roo. It usually does that when I turn it on until it warms up then it becomes more stable in frequency. But is not just the receiver, the propagation is acting strange as well having the signals in and out all the time. 73, YO6DXE
@@dxexplorer Get a whole bunch of misc mains transformers, old neon light ballasts and other inductive parts, these normally have a very high inductance (100's of millihenries up to several Henries) which are great for making audio filters, especially passive ones. The other advantage of a mains transformer is that it has a primary and secondary winding, these will be closely coupled so you could use say the primary in the actual main circuit and then resonate the secondary with caps to give you even more selectivity. Depending on the design, the high ohmic loses (and lower Q) may actually not be a problem, especially if the filter is designed for a lower impedance.
I tried some in the past but I think the Q of those transformers is not as high as the one with magnetic material as a core, so they were not as sharp. The other disadvantage if using the primary of the transformer is that it also has quite some resistance, so that also mean loosing a lot of AF signal. But when nothing else is available... they are better than nothing )). But now I am collecting these ferite cores for transformers that I find in old filters and keep them in case I want to make more custom inductors as this one. They seem to work fantastic and they don't require such a high number of turns for a certain inductance compared to a regular transformer with metallic core. 73, YO6DXE
@@dxexplorer Yep, I agree with you that the DC resistance will act against you in some configuration, especially if the winding is in series with the audio. Where they are useful is in parallel type filters such as notches. The primary goes from the audio to ground via a series capacitor to resonate it at the unwanted frequency/ies and on the secondary, you resonate with another cap (but in parallel) to "suck" out even more of the unwanted range. A series potentiometer, then allows for adjustment of how much notching you require.
good job dear friend ! will we get a passive Filter for SSB also? TNX, Heinz DE0RST
Not a bad idea. I beleive this one modified a little could do both CW and SSB. I just need a few more switches 😁. I will do some testing and come back with the results in the blog article when I have something good to share. 73, YO6DXE
Im trying to use a 110 to 6 volt transformer kg6mn
I never tried one of those but I have the feeling that due to the high number of turns in the primary, you would have a lot of loses in the audio signal. Also the Q of the inductor is a lot lower so the filter would not be as sharp. Is better if you find some magnetic core in some old power supply as I did and just make one. Better results for sure. 73, YO6DXE